Exam 1 Flashcards
(387 cards)
1
Q
(INTRACELLULAR/EXTRACELLULAR) microbes are able to survive in animals by growing extracellular being simply immersed in nutrients.
A
Extracellular
2
Q
(INTRACELLULAR/EXTRACELLULAR) microbes invade and live and replicate within animal cells where they utilize host-cell energy sources.
A
Intracellular
3
Q
This is the term for a set of cooperative defense mechanisms which provide protection from various infectious diseases.
A
Immunity
4
Q
An immune response against microbes can cause tissues injury (immunopathology), let’s call it “______ ______”.
A
Collateral damage
5
Q
Noninfectious foreign substances called _______ can also elicit an immune response.
A
Antigens (Ags)
6
Q
In some pathological conditions, self Ags in the body can elicit an _________ response.
A
Autoimmune
7
Q
Antigens (Ags) are defined as substances (either microbial or nonmicrobial) that induce an immune response. Ags can include…
A
Proteins
Carbohydrates
Lipids
Nucleic acids
8
Q
Each ______ has many microbial Ags which can be recognized by the immune system.
A
Microbe
9
Q
An _______ is a protein induced by the immune system when it detects antigens.
A
Antibody (Ab)
10
Q
An _______ (also called an antigenic determinant) is a portion of an Ag molecule to which an antibody binds.
A
Epitope
11
Q
The (SMALLEST/LARGEST) epitope (antigenic determinant) to which an antibody can be made is about 3-6 amino acids or about 5-6 sugar residues.
A
Smallest
12
Q
An Ag may contain a number of different epitopes to which individual responses (_______ or ______) are made.
A
Antibodies
T cells
13
Q
All large molecules have (ONE/MULTIPLE) epitopes.
A
Multiple
14
Q
Abs bind to conformational antigenic epitopes which are dependent on the ________ of the molecule.
A
Folding
15
Q
T cell receptors recognize _______ amino acid sequences.
A
Linear
16
Q
Ags which can stimulate an immune response are also called…
A
Immunogens
17
Q
All (IMMUNOGENS/AGS) are (IMMUNOGENS/AGS), but not all (IMMUNOGENS/AGS) are (IMMUNOGENS/AGS).
A
Immunogens; Ags
Ags; Immunogens
18
Q
Some very small Ags called ______ can bind to Abs but they cannot initiate an immune response.
A
Haptens
19
Q
(ADAPTIVE/INNATE) immunity is the first line of defense against infection that:
- Works rapidly
- Gives rise to an acute inflammation
- Has some specificity for Ag
- Has no memory
A
Innate
20
Q
(ADAPTIVE/INNATE) immunity:
- Takes longer to develop
- Is highly specific (ensures that the immune response to a microbe or nonmicroblal Ags is selective to that microbe or Ag
- Shows memory (remembers Ag it has encountered previously)
A
Adaptive
21
Q
This type of immunity develops within hours and includes phagocytes, natural killer cells, and blood components.
A
Innate
22
Q
This type of immunity develops within days or weeks and includes the generation of specific receptors.
A
Adaptive
23
Q
This component of innate immunity are small peptides which target pathogenic microorganisms ranging from viruses to parasites.
A
Antimicrobial peptides
24
Q
This component of innate immunity is a system of plasma proteins that enhances the ability of Abs and phagocytic cells to clear pathogens from an organism.
A
Complement
25
This component of innate immunity are a large group of blood proteins whose plasma concentrations change in response to tissue injury, acute infections, burns, or inflammation.
Acute phase proteins (APPs)
26
This component of innate immunity are cell signaling molecules that aid cell to cell communication in immune responses.
Cytokines
27
This component of innate immunity are a subfamily of cytokines secreted by immune cells to induce chemotaxis (movement) in nearby cells.
Chemokines
28
This component of innate immunity are immune cells that have the ability to ingest and digest microbes.
Phagocytes
29
Blood proteins including complement, acute phase proteins, cytokines, chemokines, and others are all part of innate immunity. Specifically, they are _______ innate immunity.
Humoral
30
Cells contain components such as phagocytes (macrophages, neutrophils), dendritic cells, natural killer cells, and innate lymphoid cells that are part of innate immunity. Specifically, they are _______ innate immunity.
Cellular
31
What are the cellular and chemical barriers for innate immunity?
Skin
Mucosal epithelia
Antimicrobial peptides
32
What are the cellular and chemical barriers for adaptive immunity?
- Lymphocytes in epithelia
| - Antibodies secreted at epithelial surfaces
33
For ________ immunity, there are blood protein components such as antibodies and cytokines.
Adaptive
34
For ________ immunity, there are cell components such as B and T lymphocytes.
Adaptive
35
In (INNATE/ADAPTIVE) immunity there is specificity for molecules (Ags) shared by groups of related microbes and molecules produced by damaged host cells.
Innate
36
In (INNATE/ADAPTIVE) immunity there is specificity for microbial and nonmicrobial agents.
Adaptive
37
In (INNATE/ADAPTIVE) immunity there is limited diversity, the germline is encoded.
Innate
38
In (INNATE/ADAPTIVE) immunity the diversity is very large. Receptors are produced by somatic recombination of gene segments.
Adaptive
39
Which type of immunity has memory?
Adaptive
40
T/F. Both innate and adaptive immunity are reactive to themselves.
False. They have no reactivity to self.
41
The innate and adaptive immune systems work (TOGETHER/SEPARATELY).
Together
42
T/F. Many cells and molecules of the innate immune system are also used by the adaptive immune system and vice versa.
True
43
In addition to inflammation, the innate immune system is a "______-______ ______" of an immune response.
Decision-making stage
44
Innate immunity "evaluates" the invader in the context of _______ vs. ______ microbes and then provides the instructions to adaptive immunity.
Extracellular
| Intracellular
45
The immune system "sees" pathogens as intracellular or extracellular by the components present. What components are these?
Intracellular -- Neutrophils (polymorphonuclear cells)
Antibodies
Extracellular -- Cytotoxic T cells (CTLs)
Natural Killer cells (NK cells)
Macrophages
46
Cells communicate through direct cell-to-cell contacts and through interactions involving _______ and _______.
Cytokines
| Chemokines
47
_______ are a large group of small secreted proteins with diverse structures and functions, which regulate and coordinate many activities of the cells of innate and adaptive immunity.
Cytokines
48
Functions of cytokines include --
- Regulate _______ and _______ of all immune cells
- Activate the _______ functions of lymphocytes and phagocytes.
Growth; Differentiation
| Effector
49
Each cytokine acts via a specific ________ receptor expressed on target cells.
Signaling
50
________ are a large subset of structurally related cytokines that regulate cell migration and movement.
Chemokines
51
The primary function of these is to ingest and destroy microbes and get rid of damaged tissues (scavenger function).
Phagocytes
52
Phagocytes include _______ and _______.
Neutrophils
| Macrophages
53
The steps in functional responses of phagocytes include:
1) _______ of the cells to the sites of infection
2) _______ recognition of and activation by microbes
3) _______ of the microbes by the process of phagocytosis
4) _______ of ingested microbes
Recruitment
Recognition
Ingestion
Destruction
54
This type of cell is called polymorphonuclear leukocytes because their nucleus is segmented into 3-5 connected lobules.
Neutrophils
55
These are the most abundant population of circulating spherical white blood cells of 12-15 um in diameter.
Neutrophils
56
These cells mediate the earliest phases of inflammatory reactions.
Neutrophils
57
Neutrophils are produced in the ______ ______ and arise form precursors that also give rise to mononuclear phagocytes.
Bone marrow
58
Production of neutrophils is stimulated by cytokine called...
Granulocyte colony-stimulating factor (G-CSF)
59
An adult human produces more than ______ neutrophils per day, and circulate in the blood for hours or a few days. After entering the tissues, neutrophils function only for 1-2 days and then die.
1x10(11)
60
The mononuclear phagocyte system includes circulating ________ and resident tissue ________ (play central roles in innate and adaptive immunity).
Monocyte
| Macrophages
61
Many tissues are populated with long-lived resident ________, which assume specialized phenotypes depending on the organ.
Macrophages
62
Cells of the macrophage lineage arise from committed precursor cells in the ______ ______, driven by monocyte/macrophage colony-stimulating factor (M-CSF).
Bone marrow
63
Mature monocytes enter the blood circulation and then migrate into tissues, where they further mature into macrophages, especially during _________.
Inflammation
64
Tissue-resident ________ are a heterogenous population of immune cells that fulfill tissue-specific and niche-specific functions.
Macrophages
65
Macrophage functions include --
- Dedicated _______ functions, such as clearance of cellular debris and iron processing
- Central roles in tissue immune _______
- Response to ________
- Resolution of ________
Homeostatic
Surveillance
Infection
Inflammation
66
These are cells of innate immunity that comprise a diverse group of professional antigen presenting cells (APCs).
Dendritic cells (DCs)
67
DCs share a particular morphology - long surface membrane extensions called _______.
Dendrites
68
DCs are potent stimulators of ______ to induce the adaptive immunity.
T cells
69
DCs can be broadly divided to _______ and ________ DCs.
Myeloid (mDCs)
| Plasmacytoid (pDCs)
70
mDCs (myeloid dendritic cells) are derived from monocytes and differentiated from ______ ______ _______ cells.
Peripheral blood mononuclear cells (PBMCs)
71
Other DC subpopulations include _______ cells residing in the epidermis of the skin.
Langerhan's (LCs)
72
These cells play roles in innate and adaptive immune responses and protect against helminthes and reactions that cause allergic diseases.
Mast cells
Basophils
Eosinophils
73
These cells share the common feature of having cytoplasmic granules filled with various inflammatory and antimicrobial mediators.
Mast cells
Basophils
Eosinophils
74
These cells are common at sites in the body that are exposed to the external environment, such as the skin.
Mast cells
75
Mast cells are found in close proximity to ______ ______, where they can regulate vascular permeability and effector-cell recruitment.
Blood vessels
76
Although mast cells do not have direct cell-to-cell contact with local populations, mast cells can modulate the behavior of these and other neighboring effector cells through the release of _______.
Mediators
77
There are two major types of lymphocytes, ______ and ______.
B cells
| T cells
78
Interaction between T cells and B cells, as well as between T cells and ______-______ cells, are critical to the development of specific immunity.
Antigen-presenting (APCs)
79
The development and maturation of T cells occurs in the ______. When mature T cell is Ag-stimulated it gives rise to _______ immunity.
Thymus
| Cellular
80
The development and maturation of B cells mature mainly in the _____ _____ and give rise to ______ immunity, immunity that involves production of soluble molecules, _________.
Bone marrow
Humoral
Immunoglobulins
81
Humoral adaptive immunity is mediated by _____ in the blood and mucosal secretions which are produced by B lymphocytes (B cells).
Abs
82
Abs recognize microbial ____, neutralize the infectivity of the microbes, and target microbes for elimination by various effector mechanisms.
Ags
83
Humoral adaptive immunity is the principal defense mechanism against (INTRACELLULAR/EXTRACELLULAR) microbes and their toxins because secreted Abs can bind to these microbes and toxins and assist in their elimination.
Extracellular
84
There are several classes of _____ which may activate different mechanisms to combat microbes (effector mechanisms).
Abs
85
Cell-Mediated (or Cellular) immunity is controlled by responses of ________ which often function in concert with Ag-presenting cells and phagocytes to eliminate microbes.
T lymphocytes (T cells)
86
Cell-mediated immunity mediates host defense against (INTRACELLULAR/EXTRACELLULAR) microbes, such as viruses and some bacteria, where they are inaccessible to circulating Abs.
Intracellular
87
Cell-mediated immunity function is the killing of infected _____ cells to eliminate reservoirs of infection.
Host
88
Some T lymphocytes, called _______ _______ also help B cells to make effective Abs thus contributing to eradication of extracellular microbes.
T helper lymphocytes
89
In (HUMORAL/CELL-MEDIATED) adaptive immunity, T helper cells activate macrophages to kill phagocytize microbes, or cytotoxic T lymphocytes to directly destroy infected cells.
Cell-mediated
90
This is the father of humoral immunity. He postulated that immune cells can secrete receptors (he called side chains) which recognize microbial toxins (we now call them Ags) and combat invading microbes. He also coined the term antibodies (Abs) for the serum proteins that bind toxins.
Paul Ehrlich
91
This is the father of cell-mediated immunity. In 1883, he discovered special immune cells and named them phagocytes which, he believed, are the principal effector mechanism of immunity. He was unable to prove that specific immunity to microbes could be mediated by cells.
Elie Metchnikoff
92
After Metchnikoff, the cellular theory of immunity became firmly re-established in the 1950s, when it was shown that resistance to an intracellular bacterium Listeria monocytogenes could be transferred with ______, but not with serum.
Cells
93
The immune system generates a very large number of ______ during the maturation of lymphocytes, thus maximizing the potential for recognizing diverse microbes. A ______ refers to a lymphocyte of one specificity and its progeny.
Clone
| Clone
94
All immunocompetent individuals have many distinct lymphocytes, each of which is specific for a different Ag. When Ag is introduced into an individual, lymphocytes with receptors for this Ag seek out and bind Ag and are triggered to proliferate and _________ giving rise to clones of cells specific for the Ag. The cells from the clones or their products specifically react with the Ag to neutralize or eliminate Ag.
Differentiate
95
Some Ag-specific cells late in the immune response is responsible for the '______' involved in the adaptive immunity.
Memory
96
An immune response eliminates the microbes that initiated the response. The expanded lymphocyte clones die in a ________ phase and homeostasis is restored.
Contraction
97
A few activated lymphocytes become Ag-specific ________ cells which may survive for years after the infection. These are more effective in combating microbes than are naive lymphocytes.
Memory
98
Memory cells are more numerous than naive cells specific for the Ag and respond (SLOWER/FASTER) and more effectively than do naive cells.
Faster
99
Generation of memory responses is an important goal of ________.
Vaccination
100
Ags X and Y induce the production of different Abs (specificity). The secondary response to Ag X is more rapid and larger than the primary response (memory). Abs levels (INCLINE/DECLINE) with time after each immunization (contraction of immune response).
Decline
101
The concept of ________ immunity dated to the ancient Chinese custom of making children resistant to smallpox by having them inhale powders made from the skin lesions of patients recovering from the disease.
Protective
102
An English physician ______ ______ was the first (not really) who successfully vaccinated against smallpox. He injected the material from a cowpox pustule into the arm of an 8-year-old boy. The disease did not develop when this boy was later intentionally inoculated with smallpox.
Edward Jenner
103
This is the father of immunology who developed the principle of vaccination and contributed to the foundation of immunology.
Dr. Pasteur
104
(ACTIVE/PASSIVE) immunity is conferred by a host response to a microbe or microbial Ags. (i.e., pathogen invasion or vaccination)
Active
105
(ACTIVE/PASSIVE) immunity is conferred by adoptive transfer of antibodies or T lymphocytes specific for the microbe. (i.e., Abs provided by injection, breast milk, across placenta)
Passive
106
Both active and passive immunity provide resistance to infection and are specific for microbial _____.
Ags
107
Only (ACTIVE/PASSIVE) immune responses generate immunologic memory.
Active
108
_____ lymphocytes recognize soluble Ags and develop into Ab-secreting cells.
B
109
_____ lymphocytes recognize Ags on the surfaces of Ag-presenting cells and secrete cytokines, which stimulate different mechanisms of immunity and inflammation.
T helper
110
_____ lymphocytes recognize Ags on infected cells and kill these cells.
Cytotoxic T
111
________ cells suppress and prevent immune responses (i.e., to self antigens).
Regulatory T cells
112
This is the term that indicates a defined subset of cellular surface receptors that identify cell type and stage of differentiation.
Cluster of differentiation (CD)
113
What are the two lineages that the pluripotent stem cell divides into?
Myeloid lineage
| Lymphoid lineage
114
What the primary lymphoid organs?
Thymus
| Bone marrow
115
What are secondary lymphoid organs?
Spleen
Lymph nodes
Mucosa-associated lymphoid tissue
116
All blood cells develop from common (MULTIPOTENT/PLURIPOTENT) stem cells.
Pluripotent
117
Starting from the _____ week of gestation, some stem cells migrate to the thymus and bone marrow which are referred to as the primary lymphoid organs.
13th
118
T lymphocytes are generated in the (BONE MARROW/THYMUS) where they proliferate, differentiate, and complete their maturation.
Thymus
119
B cells proliferate, differentiate, and complete their maturation in the (BONE MARROW/THYMUS).
Bone marrow
120
T/F. Ag-specific receptors are localized on the inside of T and B cels.
False. They're on the surface, not inside.
121
The structure of Ag-specific receptors varies from one cell to another but they are all _______ on a single cell.
Identical
122
Most of T cells are produced in (LATE/EARLY) life.
Early
123
The _______ is larger in infancy and during puberty, small in an adult, and replaced by fat and connective tissue in the elderly.
Thymus
124
T cells which are highly reactive with self-Ags are deleted by _______.
Apoptosis
125
T helper cells express _____ and provide help for B cell growth and differentiation.
CD4
126
Cytotoxic T lymphocytes (CTLs) express _____ and recognize and kill virus-infected cells.
CD8
127
At birth, all bone marrow is _____. During puberty, marrow increasingly converts to ______ marrow. In adults, around half of the bone marrow is ______ and half is ______.
Red
Yellow
Red; Yellow
128
Differentiation into B cells occurs within the fetal ______ and, after birth, in the bone marrow.
Liver
129
The development of B cells involves contact with _______ cells and cytokines.
Stromal
130
B cells which react with self-Ags are _________.
Eliminated
131
Ags are captured from a site of infection and the draining _____ ______ to which these antigens are transported and where the immune response is initiated.
Lymph node
132
Lymphocytes continuously circulate reaching various parts of the body except where?
Eye
Brain
Testicles
133
In search of foreign Ags, lymphocytes enter the secondary lymphoid organs via a specialized endothelium of post capillary venues called...
High endothelium venules (HEV)
134
Cells of HEV are much high than normal endothelial cells and they express high levels of adhesion molecules that serve as "______" receptors for lymphocytes.
Homing
135
Lymphocytes transmigrate by _______ from the blood into the tissue in response to chemokines.
Diapedesis
136
Lymphocytes reenter the circulation via _______ lymph vessel that merge into the thoracic duct.
Efferent
137
Ag-activated B cell proliferate and mature into _______ cells or into _______ cells. The latter being terminally differentiated B cells which produce and secrete large amounts of Abs.
Memory
| Plasma
138
In the ______, Ag-activated B cells primarily produce Abs against microbial blood.
Spleen
139
In the spleen, what makes up the white pulp?
T cells and B cells
140
The function of a plasma cell is secretion of ______.
Abs
141
In the absence of Ag stimulation, lymphoid follicles (in lymph node) are (PRIMARY/SECONDARY) follicles, composed of small naive B cells or recirculating memory B cells.
Primary
142
With Ag stimulation, B cell proliferate and differentiate converting the primary follicle into a _______ follicle or ______ ______.
```
Secondary
Germinal center (GC)
```
143
These are cells that capture, process, and display Ags to T lymphocytes and provide signals that stimulate the proliferation and differentiation of the lymphocytes.
Antigen-Presenting Cells (APCs)
144
T/F. Both T cells and B cells require APCs to display Ag to them.
False. Only T cells need them.
145
Only 3 cells can serve as APCs, which are...
Dendritic cells (DC)
Macrophages
Activated B cells
146
Only this type of cell is able to activate naive T cells in the lymph nodes.
Dendritic cells (DC)
147
Macrophages and activated B cells can present Ags only for (INACTIVATED/ACTIVATED) T cells.
Activated T cells
148
DCs and macrophages are cells of ______ immunity. Thus, they provide a link between innate and adaptive immunity.
Innate
149
DCs are part of the (MYELOID/LYMPHOID) lineage.
Myeloid
150
DCs can be broadly divided into ______ DCs, _______, and _________.
Classical
Myeloid (mDCs)
Plasmacytoid (pDCs)
151
mDCs are derived from...
Monocytes
152
Classical DCs, pDC, and Langerhan's cells (LCs) in the epidermis of the skin, develop directly from ______ cells.
Stem
153
To acquire Ags, DCs use receptor-mediated ______ and ______.
Endocytosis
| Pinocytosis
154
Activated DCs also secrete _______.
Cytokines
155
_______ DCs reside in skin, mucosa, and organ parenchyma. Upon activation by microbes, they migrate to lymph nodes where they display microbial protein Ags to T lymphocytes.
Classical
156
________ DCs are early cellular responders to viral infection. They recognize nucleic acids of intracellular viruses and produce soluble interferons (aka, IFN-alpha/beta, which has potent antiviral activities).
Plasmacytoid
157
______ or ______ is the general process of leukocyte movement from blood into tissues.
Migration
| Recruitment
158
_________ is the ability of lymphocytes to repeatedly (1) home to secondary lymphoid organs, (2) reside there transiently, and (3) return to the blood.
Recirculation
159
Leukocyte _______ is cell migration out of the blood and into peripheral tissues, or to a site of an infection or injury.
Homing
160
The recruitment of leukocytes and plasma protein from the blood to sites of infection and tissue injury is a major part of the process of _________.
Inflammation
161
Inflammation is triggered by recognition of microbes and dead tissues in ______ immune response and is refined and prolonged during _______ immune responses.
Innate
| Adaptive
162
T/F. An inflammatory response delivers the cells and molecules of host defense to the sites where offending agents need to be combated. Inflammation causes tissue damage and underlies many important diseases.
True
163
A cascade of adhesive and activation events underlies the trafficking of all subsets of circulating leukocytes which include:
1. Tethering
2. Rolling
3. ______ and stop
4. Transmigration in the tissue
Adhesion
164
Tethering occurs through transient interactions of _______ and ______ with their ligands.
Selectins
| Integrins
165
Rolling allows chemokine receptors on leukocytes to binds chemokine expressed on ________.
Endothelium
166
Receptors signal and activate interns on leukocytes which interact with ligands expressed on endothelium and trigger adhesion to the endothelium. Leukocytes then ________ into the extravascular space where they can migrate down chemokine gradients towards specific areas.
Transmigrate
167
Endothelial cells in healthy tissues do NOT express ________ molecules on their surfaces facing the blood. Endothelial cells at sites of infection and tissue injury are activated by cytokines secreted by resident immune cells at these sites and express ______ molecules.
Adhesion
| Adhesion
168
The consequence is increased adhesiveness of the endothelial cells for circulating myeloid leukocytes and Ag-activated (NOT naive) effector and ________ lymphocytes.
Memory
169
Leukocyte/lymphocyte homing and recruitment require the temporary adhesion of the leukocyte to the ________ cells of blood vessels.
Endothelial
170
T/F. Homing involves molecules on the surfaces of both the leukocytes (homing receptors and chemokine receptors) and endothelial cells (chemokines).
True
171
________ comprise a set of adhesion molecules on the surface of high endothelial venules (HEV).
Addressins
172
Selectins provide a (LOW/HIGH) affinity interaction with their ligands.
Low
173
___-selectin is synthesized and expressed on the endothelial cell surface within 1 to 2 hours in response to the cytokines IL-1 and TNF produced by Mast Cells and tissue macrophages in response to infection.
E
174
___-selectin (CD62L) is only expressed on leukocytes and lymphocytes, but not on endothelial cells. It's important for naive T and B lymphocytes for homing into lymph nodes by interacting with high endothelial venules.
L
175
L-selectin ligands expressed on HEV is called...
Peripheral node addressins (PNAd)
176
P-selectin is endothelium activated by _______ or _______.
Histamine
| Thrombin
177
What is the ligand all selectin types can use that is weak and allows leukocytes to roll?
Sialyl Lewis X
178
Integrins provide a (LOW/HIGH) affinity interaction with their ligands.
High
179
The term integrin comes from the function of these proteins -- integrate signals triggered by extracellular ligands with cytoskeleton-dependent motility, shape change, and ________ responses.
Phagocytic
180
Integrins mediate adhesion of cells to other cells or to extracellular matrix via various specific ______.
Ligands
181
All leukocytes including B and T lymphocytes, monocytes, macrophages, neutrophils, basophils, and eosinophils express...
Lymphocyte function-associated antigen 1 (LFA-1)
182
T/F. LFA-1 binds its ligand (ICAM-1, ICAM-2) expressed on cytokine-actives endothelial cells. LFA-1 is a type of selectin.
False. It's an integrin.
183
Leukocytes also express an integrin called ______ ______ ______ that binds to VCAM-1 (CD106) expressed on cytokine-activated endothelial cells.
Very Late Antigen-4 (VLA-4)
184
Leukocytes express _____ _____ integrin that binds to VCAM-1 and mucosal addressin cell adhesion molecules (MadCAM) expressed on endothelial cells.
Alpha(4)Beta(7)
185
An integrin called Macrophage-1 antigen (Mac-1) is within neutrophils, monocytes, and dendritic cells. What ligands does it bind to?
ICAM-1
| ICAM-2
186
Integrins are able to respond to intracellular signals by rapidly increasing their affinity, called integrin ________.
Activation
187
Integrin activation often occurs in all leukocytes in response to _______ binding to _______ receptors.
Chemokine
| Chemokine
188
Integrin activation is mediated by chemokine-induced conformational changes in the extracellular domains of the integrins that lead to an increased affinity. Such type of chemokine signaling is called ______-______ signaling, which is involved in integrin activation.
Inside-out
189
The integrins on blood leukocytes are normally in a (LOW/HIGH) affinity state. When rolling of leukocyte occurs, chemokines displayed on the endothelial surface can bind chemokine receptors on the leukocyte. Chemokine receptor signaling then occurs, which activates integrins of leukocyte, (DECREASING/INCREASING) their affinity for their ligands on the endothelial cells.
Low
| Increasing
190
In a ribbon diagram, when the integrin is extended that means it's showing (LOW/HIGH) affinity, and when it's bent it's showing (LOW/HIGH) affinity.
High
| Low
191
Chemokines are a large family of structurally homologous ________ of 8- to 10-kD.
Cytokines
192
The name chemokine is a contraction of...
Chemotactic cytokine
193
Chemokines stimulated leukocyte ________ and regulate the migration of leukocyte from the blood to tissues.
Movement
194
There are about 50 human chemokines which are classified into four families on the basis of the number and location of N-terminal ______ residues.
Cysteine
195
This family of chemokine has a single cysteine residue.
C chemokines
196
This family of chemokine has two defining cysteine residues that are adjacent.
CC or Beta chemokines
197
This family of chemokine has two cysteine residues separated by one amino acid.
CXC or Alpha chemokines
198
This family of chemokine has two cysteine separated by three amino acids.
CX3C chemokines
199
Neutrophils and monocytes that areas in the bone marrow and circulate in the blood are ready to be recruited into tissue sites of infection or injury without _______.
Activation
200
Neutrophils and monocytes enter the tissue (from blood) through ______-______ ______ expect parenchymal tissues (liver, lungs, kidney) where all blood cells enter through _______.
Post-capillary venules
| Capillaries
201
________ leukocytes eliminate infection pathogens, clear dead tissues, and repair the damage.
Myeloid
202
CXCL8 (IL-8) mediates the recruitment of ________.
Neutrophils
203
CCL2 (MCP-1) mediates the recruitment of ________.
Monocytes
204
Activated mast cells and resident macrophages produce cytokines TNF and IL-1 that induce the rapid expression of pre-formed ________ on the surface of endothelial cells.
P-selectin
205
_______ expression can also be induced on the surface of endothelial cells by cytokines.
E-selectin
206
The interaction between P-selectin and ligands initiates _______ on the endothelium.
Rolling
207
T/F. Rolling is further stabilized by L-selectin binding to ligands on endothelial cells.
True
208
The ________ for E-selectin and P-selectin are constitutively expressed complex sialylated carbohydrates related to the Lewis X or Lewis family.
Ligands
209
Endothelial cells presents a chemokine called ________ that is recognized by receptors on neutrophils.
Cxc-Chemokine ligand 8 (CXCL8, also called IL-8)
210
______ controls the migration of monocytes.
CCL2 (MCP-1)
211
The chemokine interaction process triggers activation of leukocyte integrins and results in more stable leukocyte _______.
Adhesion
212
Once leukocytes have complete trans-endothelial migration, they interact with _______ in the underlying basement membrane.
Chemokines
213
Following diapedesis, cells adopt an amoeboid shape. They migrate in a polarized fashion along _______ fibrils in response to a chemotactic gradient toward the site of infection/inflammation. Chemotactic receptors are located in the leading edge.
Collagen
214
Naive ____ cells preferentially leave the blood and enter lymph nodes across the high endothelial venules.
T
215
______ cells bearing Ag enter the lymph nodes through lymphatic vessels.
Dendritic
216
If the T cells recognize _____, they are activated, and return into the circulation.
Ag
217
Effector and memory _____ cells preferentially leave the blood and enter peripheral tissues through venues at sites of inflammation.
T
218
The naive lymphocytes enter the lymph nodes through an artery, leave the circulation by moving across the wall of the ______.
HEV
219
B and T cells migrate to different zones the lymph nodes drawn by ______ that are produced in these areas.
Chemokines
220
Ag-loaded dendritic cells enter the lymph node through afferent lymphatic vessels come from the sites of Ag entry. Dendritic cells migrate to the (T CELL/B CELL) rich areas of the node.
T cell
221
____-selectin is expressed by both T and B lymphocytes.
L
222
T/F. The biologic importance of L-selectin was demonstrated by experiments showing that L-selectin-deficient lymphocytes are unable to enter peripheral nodes and "see" the Ag.
True
223
L-selectin ligands expressed on HEV have been collectively called peripheral node ________.
Addressins (PNAd)
224
Lymphocytes that did not find their Ag leave the lymph node via ________ lymphatics and enter downstream lymph node.
Efferent
225
_______ lymphatics brings Ag-loaded DCs and naive T/B cells from the upstream LNs.
Afferent
226
Blood neutrophils, monocytes, and basophils don't enter the LNs and leave it via venous circulation. Naive T/B cells enter the LNs via _____. If T/B cells are activated in the LN, they also leave the LNs via venous circulation.
HEV
227
Naive T lymphocytes home to lymph nodes as a result of L-selectin binding to peripheral lymph node addressin (PNAd) on HEV. HEV are present ONLY in (PRIMARY/SECONDARY) lymphoid organs.
Secondary
228
Chemokines _____ and _____ are displayed on the surface of the HEV. Chemokines binding to _____ activates integrins.
CCL19
CCL21
CCR7
229
Naive T cells have low levels of ______ because the receptor is internalized after binding S1P in the blood.
S1PR1 (Sphingosine-1-phosphate receptor 1)
230
Naive T cells that have recently entered a LN cannot sense S1P concentration gradient between the T cell zone of the node and the lymph. Naive T cells cannot exit the node for several hours until _____ is re-expressed and the cell exit the LN by mechanism of chemotaxis.
S1PR1
231
Ag-activated T cells have low levels of ______ and the cells stay in the LN.
S1PR1
232
S1PR1 is re-expressed after several days and activated and differentiated effector T cells then sense the _____ gradient and exit the node.
S1P
233
(ACTIVATED/NAIVE) peripheral T cells home to sites of infection in peripheral tissues. Cell migration into tissue is mediated by E-selectin, P-selectin, integrins, and chemokine (CXCL10) that are produced at sites of infection.
Activated
234
_____ is important for the mobilization of effector T cells in sites of infection and inflammation. At these sites, endothelial cells secrete chemokines and express E- and P-selectin and hyaluronic acid (HA).
CD44
235
T/F. CD44 can mediate rolling interactions with vascular endothelial cells that express HA, its natural ligand, or even E-selectin.
True
236
Chemokine signaling via GPCRs results in increased integrin affinity, such as _____, which enhances adhesiveness ("inside-out" signaling).
VLA-4
237
Naive B cells use the same basic mechanisms as do naive T cells to home to secondary lymphoid tissues throughout the body. Immature naive B cells leave the bone marrow through the blood, enter the red pulp of the ______, and migrate to the periphery of the white pulp. Once the maturation is completed within the white pulp, mature naive B cells reenter the circulation and home to lymph nodes and mucosal lymphoid tissues.
Spleen
238
Homing of mature naive B cells from the blood into LNs involves rolling interaction on HEVs, chemokine activation of integrins, and stable arrest, as described earlier for naive T cells. Homing process requires chemokines _____ and _____/_____ on HEV and their chemokine receptors.
CXCL12
| CCL19/CCL21
239
In the stroma, B cells migrate into follicles driven by _____ recognized by CXCR5 expressed on naive B cells. In the follicles, B cells may encounter Ag and become activated.
CXCL13
240
(INNATE/ADAPTIVE) immunity has the ability to discriminate between self and non self. Basic mechanism involved receptors which recognize "pathogen-associated molecular patterns" (PAMPs).
Innate
241
PAMPs have no structural similarity with self Ags. Cell receptors recognizing PAMPs are termed _____ _____ _____.
Pattern Recognition Receptors (PRRs)
242
General properties of pattern recognition receptors (PRRs; recognize PAMPs) are ______-______ glycans which are essential surface molecules of bacteria and viruses, and _____-______ encoded which refers to sequences that are found in gamete producing cells.
Mannose-tailed
| Germ-line
243
Phagocytes use _____ to help distinguish self from non-self.
PRRs
244
This is present in prokaryotes but not eukaryotes (referring to PRR-Triggered responses in phagocytes)...
N-formyl methionyl peptide (fMet)
245
T/F. Polymorphonuclear cells can bind proteins starting with fMet, and use them to control motility and initiate phagocytosis.
True
246
These Toll-like receptors (TLRs) recognize extracellular pathogens.
TLR-1, -2, -4, -5, -6
247
These Toll-like receptors (TLRs) recognize intracellular pathogens.
TLR-3, -7, -8, -9
248
Some TLRs are present on the cell surface, where they recognize extracellular microbes. Other TLRs are located in endosomes, into which microbes are ingested. Eadosomal TLRs respond only to _____ _____.
Nucleic acids
249
TLRs recognize pathogens and activate ________.
Inflammation
250
MyD88 and ______ are dependent signaling, depending on the TLR being used.
TRIF
251
Which TLR uses only TRIF to activate NF-kB and IRFs transcription proteins?
TLR-3
***Besides TLR-4, the rest use ONLY MyD88
252
Which TLR uses both MyD88 and TRIF to active NF-kB and IRFs transcription proteins?
TLR-4
253
Which TLR uses both MyD88 and TRIF to active NF-kB and IRFs transcription proteins?
TLR-4
254
TLRs are expressed on immune cells, including monocytes, neutrophils, macrophages, and DCs. TLR-dependent signaling pathways activate ______ and ______ which results in the transcription of pro-inflammatory genes. Cytokine ____ controls the adaptive T-cell immune response.
NF-kB
IRF
IL-12
255
Activation of TLRs triggers antimicrobial pathways that directly kill the pathogen. Activation of TLRs can also be detrimental to the host:
- Can contribute to tissue injury by inducing _______
- Can lead to life-threatening symptoms of ______ ______
Apoptosis
| Septic shock
256
Nucleotide oligomerization domain (NOD)-like receptors (NLRs) are a specialized group of (INTRACELLULAR/EXTRACELLULAR) proteins.
Intracellular
257
NLRs play a critical role in the regulation of the host ______ immune response.
Innate
258
T/F. NLRs act as scaffolding proteins that assemble signaling platforms that trigger NF-kB and mitogen-activated protein kinase (MAPK) signaling pathways.
True
259
NLRs control the activation of ________ caspases.
Inflammatory
260
NLRs (a group of 14 receptors) responds to cytosolic PAMPs and DAMPs by binding other proteins and forming signaling complexes called _________.
Inflammasome
261
By recruitment to the complex, inflammasomes activate the enzyme _______ (a protease with cysteine residue in the active site).
Caspase-1
262
The main function of caspase-1 is to cleave the inactive cytoplasmic precursor forms of two homologous cytokines called ______ and ______. Secreted forms of pro inflammatory cytokines drive inflammation.
IL-1beta
| IL-18
263
The main function of caspase-1 is to cleave the inactive cytoplasmic precursor forms of two homologous cytokines called ______ and ______. Secreted forms of pro inflammatory cytokines drive inflammation.
IL-1beta
| IL-18
264
Inflammasome activation is induced by a wide variety of cytoplasmic stimuli that are often associated with infections and cell stress, including microbial products, environmentally or endogenously derived crystals, and reduction in cytosolic ________ ion concentrations.
Potassium
265
NLRP3 senses many DAMPs and ______, including uric acid crystals, aluminum hydroxide crystals used in vaccine adjuvants, ATP released from mitochondria, silica, bacterial products, bacterial toxins produced by streptococci and staphylococci, bacterial DNA-RNA hybrid, and the influenza virus.
PAMPs
266
Inflammasome activation also causes an inflammatory form of programmed cell death of macrophages and DCs (but not of neutrophils and most other cell types) called ________, characterized by swelling of cells, loss of plasma membrane integrity, and release of inflammatory mediators including IL-1beta, IL-18, TNF, IL-6, and IL-8.
Pyroptosis
267
________ receptors are important in tissue remodeling after collateral damage due to inflammation and infections.
Scavenger
268
The scavenger receptor (SR) family consists of:
- Scavenger receptor class _______
- Scavenger receptor class _______
- _______
Class A type I
Class A type II
MARCO (Macrophage Receptor with Collagenous Structure)
269
Scavenger receptors are trimeric complexes of type II transmembrane ________.
Polypeptides
270
Scavenger receptors have 3 distinct extracellular structural domains:
A) SR ______-rich domain (Absent in SR-A II)
B) The ______-like domain, which is implicated in the dining of polyanionic ligands
C) The alpha-helical coiled-coil domain (absent in ______)
Cysteine
Collagen
MARCO
271
Scavenger receptors are ______ ______ receptors and are most commonly found on immune cells.
Pattern recognition receptors (PRRs)
272
SR-AI and SR-AII mediate the uptake of oxidized lipoproteins into cells which lead to _________.
Atherosclerosis
273
All SRs bind various bacterial constituents based on (NEGATIVE/POSITIVE) charges on bacterial LPS, lipoteichoic acid, nucleic acids, Beta-glucan, and proteins.
Negative
274
SR-AI, SR-AII, and MARCO are expressed on ________ and mediate recognition/phagocytosis of microorganisms via recognition of PAMPs leading to the clearance of pathogens.
Macrophages
275
These receptors belong to the C-type ______ family because they bind carbohydrates. All contain a conserved carbohydrate recognition domain for recognition of microbial mannose, N-acetylglucosamine, and Beta-glucans. To compare, eukaryotic cell carbohydrates are most often terminated by galactose and sialic acid.
Lectin
276
Some of the lectins are soluble proteins found in the blood and extracellular fluids. Other lectins are integral _______ proteins found on the surface of macrophages, DCs, and some tissue cells.
Membrane
277
The function of lectin receptors is to facilitate _________ of the microbes.
Phagocytosis
278
Lectin receptors trigger secretion of _______ that promote adaptive immune responses.
Cytokines
279
_______ receptors are one of the most studied membrane C-type lectins which recognize terminal D-mannose, L-fucose, and N-acetyl-D-glucosamine sugars on microbial surface.
Mannose
280
T/F. The mannose receptor (C-type lectins) on phagocytes is involved in phagocytosis of microbes.
True
281
Soluble mannose-binding lectin (MBL), also known as mannan-binding protein (MBP), is a protein that is involved in _______ activation via the lectin pathway.
Complement
282
This term is for a passive, catabolic cell death in response to external toxic factors. It is a "dirty" form of cell death characterized by swelling and rupture of cell membrane (cell lyse) which may cause inflammation or harm other neighboring cells.
Necrosis
283
Inflammation is an innate reaction caused by...
1. An increased ______ supply to the affected area -- redness and heat
2. An increased _______ permeability -- leak from the blood vessels -- swelling and pain
3. A massive influx of _______ in the tissue
4. An arrival of monocytes/macrophages (16-48 hrs)
5. Distortion of the homeostasis and loss of function
Blood
Capillary
Neutrophils
284
_______ are small antimicrobial cationic peptides that contain both cationic and hydrophobic regions. They are produced by epithelial cells of mucosal surfaces and by granule-containing leukocytes, including neutrophils, NK cells, and CTLs. Their synthesis is stimulated by cytokines and microbial products via (PRRs).
Defensins
285
Defensins have direct toxicity to microbes, including bacteria, fungi, and enveloped viruses. Defensins kill microbes by inserting into and disrupting functions of the microbial ________.
Membranes
286
T/F. Defensins regulate activation of immune cells involved in the inflammatory response to microbes.
True
287
These can play an anti-inflammatory role by binding to DNA and blocking inflammasome activation. They are an antimicrobial.
Cathelicidins
288
_____ _____ cells are part of innate immunity. They recognize ligands on infected cells or cells undergoing other types of stress. They kill those infected or stressed host cells. They eliminate reservoirs of infection and thus release intracellular pathogens for phagocytosis.
Natural killer
289
NK cells respond to IL-12 produced by macrophages and secrete _____. This is what activates the macrophages to kill phagocytize microbes.
IFN-y
290
Activating receptors of NK cells recognize ligands on target cells and active protein tyrosine kinases (PTKs). NK cell activating receptors are called...
Killer Cell Immunoglobulin-like Receptors (KIRs)
291
NK cell inhibitory receptors that recognize class I MHC molecules and activate protein tyrosine phosphatases (PTP) inhibits an activation signal. Thus, NK cells do not kill class I MHC -- expressing _______ cells.
Healthy
292
Most NK cells express inhibitory receptors that recognize class I MHC molecules. If a virus infection or other stress inhibits class I MHC expression on infected cells, the NK cell inhibitory receptor is not engaged, thus activating the receptor functions and allowing the NK cells to kill and produce cytokine _____ (induces phagocytosis by macrophages).
IFN-y
293
NK cells recognize cellular stress and become activated via activating receptors which bind ______ and ______ ligands. These ligands are generally absent on the cell surface of healthy cells but are unregulated upon cellular stress associated with viral infection and malignant transformation.
MICA
| MICB
294
The _______ system consists of several plasma proteins that work together to opsonize microbes, to promote the recruitment of phagocytes to the site of infection, and, in some cases, to directly kill the microbes.
Complement
295
The activation of the complement system may initiated by three distinct activation pathways, which are...
Classical pathway
Alternative pathway
Lectin pathway
296
The early step 1 of complement pathway is formation of C3 convertase complexes that produce _____ and _____ which trigger inflammation and opsonize microbes.
C3a
| C3b
297
The early step 2 of complement pathway is formation of C5 convertase complexes that produce _____ and _____ which perpetuate inflammation and initiates late steps.
C5a
| C5b
298
The late steps in the complement pathway are formation of membrane attack complexes which form _____ in microbial membranes.
Holes
299
Complement activation involves proteolytic cascades in which an inactive precursor enzyme, called a ______ is altered to become an active protease that cleaves the next complement protein in the cascade.
Zymogen
300
T/F. Enzymatic cascades result in tremendous amplification of the amount of proteolytic products that are generated. Byproducts of complement activation perform various effector functions of the complement system.
True
301
The complement system works in cooperation with other medically important proteolytic cascades including:
- The blood _______ pathways
- The ______-______ system that regulates vascular permeability
Coagulation
| Kinin-Kallikrein
302
Recognition of microbes by any of the three complement pathways results in sequential recruitment and assembly of additional complement proteins into protease complexes.
- C3 convertase cleaves C3 producing _____ fragment and ______ fragment
- C5 convertase cleaves C5 producing _____ fragment and _____ fragment.
C3a; C3b
| C5a; C5b
303
Soluble _____ fragment stimulates inflammation by acting as a chemoattractant for neutrophils.
C3a
304
_____ fragment becomes covalently attached to the microbial surface and serves as an opsonin to promote phagocytosis of the microbes.
C3b
305
_____ convertible binds _____ fragment to form a protease called C5 convertase.
C3
| C3b
306
Soluble ____ is a very potent chemoattractant that also induces changes in the permeability of blood vessels.
C5a
307
_____ is attached to bacterial membrane that initiates the formation of complex of C6, C7, C8, and C9 complement proteins called the membrane attack complex (MAC). Multiple MACs cause bacterial leak and lysis.
C5b
308
The alternative pathway is capable of auto activation because of a process termed "tickover" of C3. Tickover occurs spontaneously at a rate of about 1% of total C3 per hour, generating ____ and ____.
C3a
| C3b
309
In the alternative pathway, C3b is capable of binding factor B that can be cleaved into ____ and ____ by the constitutively active serum protease factor D.
Ba
| Bb
310
In the alternative pathway, the Bb associates with C3b and C3 convertase formed _____ can then cleave additional C3 molecules generating C3b.
C3bBb
311
In the alternative pathway, the successive proteolytic steps is enhanced by the serum protein _______, which stabilizes protein:protein interactions during the process.
Properdin
312
The classical pathway is _____ mediated.
Ab
313
In the classical pathway, a plasma protein called ____ recognizes and binds to Ag-Ab complexes.
C1q
314
In the classical pathway, once C1q binds to the Fc portion of Abs, two associated serine proteases, called ____ and ____, become active.
C1r
| C1s
315
In the classical pathway, C1r activates _____ so that it in turn can activate _____ and _____.
C1s
C2
C4
316
In the classical pathway, complex ______ is the classical C3 convertase and ______ is the classical C5 convertase.
C4bC2a
| C4bC2aC3b
317
The lectin pathway is triggered by a plasma protein called _______-binding lectin.
Mannose
318
In the lectin pathway, mannose-binding lectin (MBL) recognizes terminal mannose residues on microbial glycoproteins and glycolipids (similar to the mannose receptor on phagocytes). MBL has a hexametric structure, and after it binds to microbes, two zymogens called ______ and ______ are activated.
MASP1
| MASP2
319
MAPS1 and 2 have similar functions to C1r and C1s and initiate downstream proteolytic steps identical to the _______ pathway.
Classical
320
In the alternative pathway, ______ acts as C3 convertase and _____ as C5 convertase.
C3bBb
| C3bBbC3b
321
The _____ is identical for all 3 pathways.
MAC (membrane attack complex)
322
____ prevents the assembly of the C3 and C5 convertase.
FI
323
Complement is not activated on the surface of mammalian cells because they express ______ proteins that inhibit, disassemble, or cleave the converses.
Regulatory
324
Some bacteria can survive in phagolysosome because they express ______.
Catalase
325
TNF, IL-1, and IL-6 mediate protective systemic effects of inflammation, including induction of fever, acute-phase protein synthesis by the liver, and _______ -- an increased produced of leukocytes by the bone marrow.
Leukocytosis
326
Several plasma proteins that recognize microbial structures and participate in innate immunity belong to the ______ family. C-reactive protein (CRP) and serum amyloid P (SAP) are acute phase proteins form this family.
Pentraxin
327
Plasma concentrations of CRP and SAP are very low in healthy individuals but can increase up to 1000-fold during infections and in response to other inflammatory stimuli. This is due to an increased synthesis by the _______ induced by cytokines IL-6 and IL-1.
Liver
328
CRP and SAP recognize _______ and _______, respectively, which are found on bacteria and apoptotic cells.
Phosphorylcholine
| Phosphatidylethanolamine
329
CRP and SAP can activate _______ by binding C1q and initiating the classical pathway.
Complement
330
Abs have 2 heavy and 2 light chains, each are divided into V and C regions. The V region contains the _____ binding site and the C region determines the fate of the Ag.
Ag
331
Abs can be proteolytically cleaved to yield two _____ fragments and an ____ fragment responsible for effector functions.
Fab
| Fc
332
IgG is cleaved by the enzymes _______. Digestion of this allows separating of two Fab fragments and complement and Fc receptors-binding the Fc fragment.
Papain
333
Abs have a basic unit of four polypeptide chains bound together by covalent ______ ______ as well as by non covalent interactions.
Disulfide bridges
334
There are five different kinds of H-chains and two different kinds of L-chains, ____ and ____.
K and y (upside down)
335
T/F. Each antibody unit can have only K or y (upside down) L-chain, but not both.
True
336
Both H- and L- chains have intrachain ______ ______ every 90 amino acid residues, which create polypeptide loops or domains, of 110 amino acids.
Disulfide bridges
337
Secreted IgG have Ag-binding sites on VL and Vh domains and the heavy chain C regions end in _____ pieces.
Tail
338
Membrane-bound IgM on B cell has an additional Ch4 domain and has ___-terminal transmembrane and cytoplasmic portions that anchor the molecule in the plasma membrane.
C
339
Flexibility of Ab is due to the _____ regions located between Ch1 and Ch2.
Hinge
340
IgG is binding to two (WIDELY/CLOSELY) spaced determinants (epitopes) on a cell surface, while the same IgG can bind two determinants (epitopes) that are (WIDELY/CLOSELY) spaced.
Widely
| Closely
341
The tightness of Ag-Ab binding is called...
Affinity
342
Abs formed in the ______ response soon after the injection of an Ag are generally of lower infinity.
Primary
343
Abs produced by a _______ response have high affinity than those in a primary response. Affinity of an Ab is critical when the Ag is a toxin or virus and must be neutralized rapidly at low titers.
Memory
344
The ______ of an Ab is the maximum number of antigenic determinants with which it can react.
Valence
***Molecule of IgG contain two Fab regions and can bind two molecules of Ag on two identical sites on the same particle, and thus have a valence of two.
345
The valence is important for binding affinity, as having two or more binding sites for an Ag can dramatically increase the _______ of the binding of the Ab to Ags.
Tightness
346
_______ gives a measure of the overall strength of an Ab-Ag complex. It is dependent on the affinity of the Ab for the epitope and the valence of both the Ab and Ag.
Avidity
347
This antibody is the most common in mucosal secretions.
IgA
348
This antibody is mainly found in the plasma.
IgM
349
This antibody is absorbed on the surface of mast cells.
IgE
350
This antibody penetrates deeper into the tissue.
IgG
351
This is the most abundant Ab in the blood and provides the bus of immunity to most bloodborne pathogens.
IgG
352
This is the only Ab to cross the placenta to provide passive humoral immunity to the developing fetus and to the infant on its birth.
IgG
353
This Ab is present in low quantities in the circulation. Its primary function is as an Ag receptor on B lymphocytes.
IgD
354
This Ab acts as a BCR on B cell. It is the first Ab produced by any Ag-activated B cell prior to contact with T cell. It plays a CRITICAL role in defense before sufficient quantities of IgG have been synthesized.
IgM
355
IgM on a B cell is expressed a (FOUR/FIVE) chain unit, but the blood IgM is composed of five (FOUR/FIVE) chain units held together by disulfide bridges.
Four
| Four
356
This Ab is a big molecule, hence why it's found primarily in the bloodstream.
IgM
357
The overall avidity of an IgM is high, making it (GOOD/BAD) at removing a microbe.
Good
358
This Ab is present in external secretions such as colostrum, milk, and saliva.
IgA
359
Secretory ____ bind to (pathogen-derived) antigens and prevent or inhibit their attachment to and/or invasion of epithelial cells.
IgA
360
This Ab is present in the serum at very low levels. It plays a significant role in enhancing acute inflammation, in protection from infection by worms and in allergic reactions.
IgE
361
IgE produced binds to receptors on ______ cells which are specific for the Fc region of IgE. When Ag is reintroduced to such "sensitized" _____ cells, it binds to IgE molecule on the cell and triggers activation and the release of mediators.
Mast
| Mast
362
IgE is an important component of immediate hypersensitivity syndromes such as hay fever and _____.
Asthma
363
Ags in host cells are broken up into linear peptides and displayed by MHC molecules expressed on their cell surface. The ___ cell antigen receptor ONLY recognizes peptides bound to MHC molecules.
T
364
CD4+ T helper cells recognize peptide Ags in the context of MHC class (I/II) molecules that are expressed by dendritic cells, macrophages, and B cells.
II
365
CD8+ cytotoxic T cells recognize peptides associated with MHC class (I/II) molecules.
I
366
This differential requirement for CD4 and CD8 relates to the fact that CD4 and CD8 attach to __________ (non-variant) part of the MHC class II and MHC class I molecules, respectively.
Non-polymorphic
367
T/F. Recognition of the peptide Ag by the TCR is not sufficient to activate the cells. APCs express co-stimulatory molecules are also required together with CD4 and CD8 co-receptors involved in signaling events.
True
368
T cell activation leads to production of _____ which controls clonal expansion (proliferation) of the specific T cells.
IL-2
369
There two phenotypes of T helper cells, _____ and _____, each with different functions in the immune response that are dictated by their cytokines produced.
Th1
| Th2
370
Activated Th1 cells help macrophages get rid of intracellular microbes and help the development of cytotoxic T cells to kill virus-infected cells. Cytokine _____ produced by Th1 cells activates macrophages.
IFN-y
371
Activated Th2 cells are mainly involved in responses against extracellular microbes helping B cells to develop into memory cells and plasma cells that produce antibodies. Cytokine _____ produced by Th2 cells is important for B cell proliferation.
IL-4
372
The T cell receptor (TCR) of "conventional" is composed of two polypeptide chains, ____ and ____, which are the Ag-binding site. Some T cells, whose function is not completely understood, express a TCR consisting of ____ and _____ chains.
Alpha
Beta
Gamma
Delta
373
Unlike Abs, TCRs do not recognize native antigen, but can only bind processed Ag presented in _____ molecules.
MHC
374
MHC Class ___ molecules are composed of a polymorphic alpha chain non-covalently attached to the non-polymorphic Beta2-microglobulin. The alpha chain is glycosylated.
I
375
MHC Class ____ molecules are composed of a polymorphic alpha chain non-covalently attached to a polymorphic Beta chain. Both chains are glycosylated.
II
376
Peptides that bind to class I MHC molecules are derived from viruses and other (INTRACELLULAR/EXTRACELLULAR) microbes that have infected host cells and move as the complexes to the surface (endogenous pathway).
Intracellular
377
Peptides that bind to class I MHC are recognized by _____ cytotoxic T lymphocytes.
CD8+
378
Ags and (INTRACELLULAR/EXTRACELLULAR) pathogens taken from the environment are primarily presented on class II MHC molecules to _____ helper T cells.
CD4+
379
MHC class II molecules are expressed on profession APCs, which are...
B cells
DCs
Macrophages
380
What costimulatory protein found on professional APCs is required for their activation?
CD40
381
Microbial Ags commonly enter through the skin and GI and respiratory tracts, where they are captured by ______ cells and transported to regional lymph nodes.
Dendritic
382
Ags that enter the blood stream are captured by APCs in the _______.
Spleen
383
NK cells produce _____ during innate immune reactions to microbes or by T cells during adaptive immune reactions.
IFN-y
384
IFN-y stimulates MHC class ___ expression on APCs and thus enhances the activation of CD4+ T cells.
II
385
IFN-y and interferons have a similar effect on the expression of MHC class ____ molecules and the activation of CD8+ T cells.
I
386
The HLA-DM editing mechanism works to ensure the presentation of only the protein fragments most relevant for eliciting an immune response. HLA-DM has 3 major functions:
- HLA-DM causes the dissociation of _____ from the peptide binding groove of MHC II
- HLA-DM stabilizes and prevents degradation of the empty MHC II
- HLA-DM facilitates the binding of Ag fragments to the open, stabilized binding groove.
CLIP
387
Fragments of cells infected with intracellular microbes are ingested by DCs. Ags of the infectious microbes are transported into the cytosol and processed and presented in association with class I MHC molecules to CD8+ T cells. Thus, DCs are able to present ________ Ags by the class I pathway.
Extracellular
