Week 2 Lec: Lymphoid System Flashcards
1
Q
All those physiological mechanisms that endow the animal with the capacity to recognize materials as foreign to itself and to neutralize, eliminate, or metabolize them with or without injury to its own tissues.
A
Immunity
2
Q
The _______ is structured to recognize, respond to, and destroy a wide variety of invading organism that would otherwise be capable of promoting infections, harmful to the body.
A
immune system
3
Q
The ability of an individual to resist infections by means of normally present body functions.
A
Natural Immunity
4
Q
It is considered as first line of defense. Physical barriers such as our skin, and secretions.
A
External defense system
5
Q
It is considered as second line of defense. The most important process is process of phagocytosis. It is incorporated with the different types of WBC such as the polymorphonuclear cells, monocytes, and macrophages.
A
Internal defense system
6
Q
The type of resistance that is characterized by specificity for each individual pathogen, or microbial agent. Referred to as the 3rd line of defense.
A
Acquired Immunity
7
Q
Lymphocytes represent _____ of the circulating WBCs.
A
20-40%
8
Q
What is the second most common type of leukocyte?
A
Lymphocyte
9
Q
The typical small lymphocyte is between _____ in diameter.
A
7 and 10 μm
10
Q
Nucleus characteristics of lymphocyte?
A
a large rounded nucleus that may be somewhat indented
11
Q
Color of lymphocyte when stained?
A
lighter blue appearance
12
Q
Cytoplasm characteristics of lymphocytes?
A
- sparse
- few organelles
- no specific granules
- narrow ring surrounding the nucleus
13
Q
Why are lymphocytes unique?
A
because they arise from a hematopoietic stem cell and are further differentiated in the primary lymphoid organs
14
Q
2 main classifications of lymphocytes depending on where lymphocyte differentiation takes place?
A
Primary and Secondary Lymphoid Organs
15
Q
Main function of Primary Lymphoid Organs?
A
maturation of B and T cells
16
Q
Main function of Secondary Lymphoid Organs?
A
proliferation and differentiation of B and T cells
17
Q
Lymphocyte circulation is complex and is regulated by different cell surface adhesion molecules and by chemical messengers called?
A
cytokines
18
Q
They influence other activities of the cell.
A
cytokines
19
Q
3 major populations of lymphocytes?
A
- T cells
- B cells
- Natural Killer cells
20
Q
T cells account for how many percent in the total population of lymphocytes?
A
61-80%
21
Q
B cells account for how many percent in the total population of lymphocytes?
A
20%
22
Q
Natural killer cells account for how many percent in the total population of lymphocytes?
A
10-15%
23
Q
Once T and B cells mature, they go to?
A
Secondary Lymphoid Organs
24
Q
What is the precursor cell mainly associated with B, T, and NK cells?
A
common lymphoid precursor
25
Primary Lymphoid Organs consist of?
* Bone marrow
* Thymus
26
Secondary Lymphoid Organs consist of?
* Spleen
* Lymph nodes
* Mucosal-Associated Lymphoid Tissue (Appendix, Tonsils, Peyer’s Patches)
* Cutaneous-Associated Lymphoid Tissue
27
It consists of flat, long bones that is a source of hematopoietic stem cells.
Bone marrow
28
All lymphocytes arise from?
pluripotential hematopoietic stem cells
29
Aside from lymphocytes, it accounts for the different cell types such as RBC, WBC, macrophages and megakaryocytes/thrombocytes/platelets.
pluripotential hematopoietic stem cells
30
Weight of bone marrow in humans?
1,300-1,500 g (adult)
31
It fills the core of all long bones and is the main source of hematopoietic stem cells, which develop into different cell types.
Bone marrow
32
_____________ are released from the marrow and travel to additional primary lymphoid organs where further maturation takes place.
Lymphocyte stem cells
33
The mother cell of all cells.
hematopoietic stem cell
34
Hematopoietic stem cells give rise to what 2 different cell lines?
CLP (Common Lymphoid Precursor) and CMP (Common Myeloid Precursor)
35
Common Lymphoid Precursor gives rise to which cells?
* T cell
* B cell
* Dendritic cell
* Natural Killer cell
36
Common Myeloid Precursor gives rise to which cells?
* monocytes
* eosinophils
* basophils
* neutrophils
* erythrocytes
* platelets
37
It is an organ which is small, flat, bilobed organ found in the thorax, or chest cavity, right below the thyroid gland and overlying the heart.
Thymus
38
Weight of thymus at birth?
30 g
39
Weight of thymus at puberty?
35 g
40
A decrease in the size of thymus when it reaches its matured/maximum form is an example of what process?
atrophy
41
Each lobe of the thymus is divided into _____ filled with _____ that play a central role in this differentiation process.
lobules, epithelial cells
42
________ are acquired as the lymphocytes travel from the cortex to the medulla over a period of 2 to 3 weeks.
Surface antigens
43
Part of the thymus where T cells stay before they mature.
Cortex
44
Once matured T lymphocytes are formed, they are then released from the?
Medulla
45
Each lymphocyte spends most of its life span in ___________, entering the circulation only periodically to go from one secondary organ to another.
solid tissue
46
A specific lymphocyte may make the journey from blood to secondary lymphoid organs and back _____ times per day.
one to two
47
Largest secondary lymphoid organ.
Spleen
48
Dimensions and weight of the spleen?
12cm in length and weighs 150g in adult
49
A large discriminating filter that can remove foreign antigens and all RBCs from the blood.
Spleen
50
Spleen is located?
in the upper-left quadrant of the abdomen, just below the diaphragm
51
Spleen is surrounded by a?
thin connective tissue capsule
52
Splenic tissue can be divided into two main types?
1. Red Pulp
2. White Pulp
53
It makes up more than one half of the total volume, and its function is to destroy old red blood cells.
Red Pulp
54
In the red pulp of the spleen, blood flows from the arterioles into the red pulp and then exits by way of the?
splenic vein
55
It comprises approximately 20 percent of the total weight of the spleen.
White Pulp
56
The White Pulp comprises approximately ___ percent of the total weight of the spleen.
20
57
The White Pulp contains the lymphoid tissue, which is arranged around arterioles in a?
periarteriolar lymphoid sheath
58
Attached to the periarteriolar lymphoid sheath are?
primary follicles
59
It contains B cells that are not yet stimulated by an antigen.
primary follicles
60
Surrounding the PALS is a ___________ containing dendritic cells that trap antigen.
marginal zone
61
The marginal zone contains what cells that trap antigen?
dendritic cells
62
The most potent phagocytic cell and is considered as the best APC (Antigen Presenting Cell).
dendritic cell
63
Each day, an adult blood passes through the spleen approximately ___ times.
4
64
Why does the blood pass through the spleen ~4 times a day?
it allows lymphocytes and macrophages to constantly survey for infectious agents or other foreign matters
65
When B cells contained in the primary follicle are stimulated by an antigen, it results to a structure called?
germinal center
66
Tagalog term for lymph nodes?
kulani
67
Located along lymphatic ducts and serve as central collecting points for lymph fluid from adjacent tissues.
Lymph Nodes
68
Lymph Nodes are located along?
lymphatic ducts
69
Functions of lymph nodes?
* collecting points for lymph fluid from adjacent tissues
* contribute for the ideal environment of foreign antigens
70
Lymph nodes are especially numerous near?
joints and where the arms and legs join the body
71
Size of lymph node?
1 mm to 25 mm in diameter
72
Major purpose of lymph nodes?
filtration
73
The lymph fluid flows slowly through spaces called ______, which are lined with macrophages, creating an ideal location for phagocytosis to take place.
sinuses
74
The lymph fluid enters the lymph nodes via?
afferent lymphatic vessel
75
The lymph fluid exits the lymph nodes via?
efferent lymphatic vessel
76
Swelling of lymph nodes?
Lymphadenopathy
77
Region of lymph nodes: the outermost region. An aggregation of lymph nodes. Contains macrophages and aggregations of B cells in primary follicles, follicular dendritic cells, secondary follicles (germinal center), plasma cells, and memory cells.
Cortex
78
Consists of stimulated B cells and site where germinal center is seen.
Secondary follicles
79
They are fully differentiated lymphocytes found in the cortex of lymph nodes for antibody production and secretion.
Plasma cells
80
Region of lymph nodes: where T cells are found. Region between the cortex and medulla.
Paracortex
81
Region of lymph nodes: contains some T cells, B cells and numerous plasma cells.
Medulla
82
3 Mucosal-Associated Lymphoid Tissue?
* Appendix
* Tonsils
* Peyer’s Patches
83
Locations of Mucosal-Associated Lymphoid Tissue (MALT)?
* urogenital tract
* respiratory tract
* gastrointestinal tract
84
Located at the junction of the small and large intestines.
Appendix
85
Lymphoid tissue found in the mucous membrane lining of the oral and pharyngeal cavities that trap foreign particles. It responds to pathogens entering the respiratory and alimentary tract.
Tonsils
86
Located at the lower ileum of the intestinal tract.
Peyer’s Patches
87
A collective term for monocyte, macrophages, and dendritic cells (intraepidermal lymphocytes) in the epidermis. It also contains T cells. They are uniquely positioned to combat any antigens that enter through the skin.
Cutaneous-Associated Lymphoid Tissue (CALT)
88
True or false: Within each of the secondary organs, T and B cells are segregated and perform specialized functions.
True
89
B cells differentiate into memory cells and plasma cells and are responsible for?
Humoral Immunity or Antibody Production
90
T cells play a role in ________ , and as such, they produce sensitized lymphocytes that secrete ________.
Cell-Mediated Immunity, Cytokines
91
_______ are small polypeptides that regulate the functions of lymphocytes and other cells involved in the immune response.
Cytokines
92
These are proteins or antigens used to distinguish the developmental stage of each cell and serve as markers to differentiate T cells and B cells.
Surface Markers
93
Surface Markers have been detected by ___________, which are extremely specific antibodies made by cloning a single antibody-producing cell.
monoclonal antibodies
94
True or false: Several laboratories have developed monoclonal antibodies, and each used its own nomenclature for the set of antigens found.
True
95
Panels of antibodies from different laboratories were used for analysis, and antibodies reacting similarly with standard cell lines were said to define?
Cluster of Differentiation
96
CD marker for T cells?
CD 2, 3, 4, 8
97
CD marker for B cells?
CD 19, 21, 23
98
CD marker for NK cells?
CD 16, 56, 94
99
4 steps of B-Cells Differentiation?
1. Pro-B cells
2. Pre-B cells
3. Immature B cells
4. Mature B cells
100
(Pro-B cells) First step is the ______________ of an antibody molecule.
rearrangement of genes that code for the heavy and light chains
101
(Pro-B cells) The end result is a B lymphocyte programmed to produce a unique antibody molecule, which consists of ________________.
two identical light chains and two identical heavy chains
102
(Pro-B cells) Heavy Chains are coded on chromosome?
14
103
(Pro-B cells) Light Chains are coded on chromosome?
2 and 22
104
The pro-B cell has distinctive markers that include surface antigens?
* CD19
* CD45R
* CD43
* CD24
* c-Kit
105
(Pro-B cells) CD markers that will remain in the cell surface?
* CD19
* CD45R
* CD24
106
A tyrosine-specific phospate which is the main CD marker that can recognize Pro-B cells.
CD45R
107
(Pro-B cells) Intracellular proteins found at this stage are terminal __________ and recombination-activating genes _____ and ______, which code for enzymes involved in gene rearrangement.
deoxyribonucleotide transferase (TdT); RAG-1 and RAG-2
108
(Pro-B cells) These are DNA that live at certain possible recombination site.
RAG-1 and RAG-2
109
(Pro-B cells) Helps to join the pieces back together by incorporating additional nucleotides in the joining area.
terminal deoxyribonucleotide transferase/TdT
110
(Pre-B cells) The first heavy chains synthesized are the __________, which belong to the class of immunoglobulins called _____.
μ chains; IgM
111
Pre-B cells begin to form when?
rearrangement of heavy chain occurs
112
Pre-B cells also lose which CD markers?
* CD43 marker
* c-Kit
* TdT
113
Pre-B cells may also express μ chains on the cell surface, accompanied by an unusual light chain molecule called a?
surrogate light chain
114
(Pre-B cells) Surrogate light chains consist of __________ that are noncovalently associated with each other.
two short polypeptide chains
115
(Pre-B cells) Surrogate light chains consist of two short polypeptide chains that are __________ associated with each other.
noncovalently
116
(Pre-B cells) The combination of the two heavy chains with the surrogate light chains plus two very short chains, Ig-α/Ig-β form the?
pre-B cell receptor
117
Function of the pre-B cell receptor?
adheres to the bone marrow stromal cell membrane and transmits a signal to prevent rearrangement of any other heavy chain genes
118
True or false: It appears that all pre-B cells, whether expressing the μ heavy chains in association with surrogate light chains or not, survive and proceed to further differentiation.
False. Only pre-B cells expressing the μ heavy chains in association with surrogate light chains survive.
119
True or false: Once the pre-B receptor (pre-BCR) is expressed, neighboring pre-B cells may send signals for further maturation.
True
120
Rearrangement of genetic sequence coding for light chains on either chromosome 2 or 22 happens to form?
Immature B cells
121
Immature B cells are mainly distinguished by the appearance of _____ molecule on the cell surface.
IgM
122
(Immature B cells) In the reaarangement of light chains, Kappa chain is in line with chromosome _____.
2
123
(Immature B cells) In the reaarangement of light chains, Lambda chain is in line with chromosome _____.
22
124
(Immature B cells) True or false: Once surface immunoglobulins appear, μ chains are no longer detectable in the cytoplasm.
True
125
Other surface proteins that appear on the immature B cell include?
* CD 21
* CD 40
* major histocompatibility complex (MHC) class II molecules
126
Functions of the CD21 marker in immature B cells?
* acts as a receptor together with CD19
* a receptor for breaking down complement component C3 to become C3D, which acts as an adjuvant to increase humoral immune response
* receptor for Epstein–Barr virus (EBV), the causitive agent of infectious mononucleosis
127
Acts as coreceptor with CD21 that helps regulate further B cell development and activation.
CD19
128
Acts as an adjuvant to increase humoral immune response. It is mainly involved in the production of antibodies.
C3D
129
Immature B cells leave the __________ and proceed to seed the ______________.
bone marrow; spleen and other secondary lymphoid organs
130
In the spleen, immature B cells develop into mature cells known as?
marginal zone B cells
131
In addition to IgM, all mature B cells exhibit?
IgD
132
The mature B cells remain in the spleen in order to?
respond quickly to any blood-borne pathogens they may come into contact with
133
Other immature B cells become __________ which are found in __________ and other secondary organs.
follicular B cells; lymph nodes
134
If B cell is stimulated by antigen, it undergoes transformation to a ________, which eventually forms memory cells and antibody secreting plasma cells.
blast stage
135
Activated B cells exhibit identifying markers that include _____, which is found on both activated T and B cells and acts as a receptor for ________, a growth factor produced by T cells.
CD25; interleukin-2 (IL-2)
136
Characteristic of plasma cells?
* spherical or ellipsoidal cells
* between 10 and 20 μm in size
* characterized by the presence of abundant cytoplasmic immunoglobulin and little to no surface immunoglobulin
137
Represents the most fully differentiated lymphocyte.
Plasma Cells
138
Main function of plasma cells?
antibody production/secretion
139
True or false: Plasma cells are nondividing, and after several days of antibody production, they die without further proliferation.
True
140
It is estimated that approximately ___________ of the cortical cells die intrathymically before becoming mature T cells.
97 percent
141
Lymphocyte precursors called _________ enter the thymus from the bone marrow.
Thymocytes
142
Within the lobules of the thymus are two main zones?
* Outer cortex
* Inner medulla
143
Thymic stromal cells include _____________, all of which play a role in T-cell development.
* epithelial cells
* macrophages
* fibroblasts
* dendritic cells
144
In T-cell development, interaction with __________ under the influence of ___________ is critical for growth and differentiation.
stromal cells; cytokines
145
Cytokine involved in T-cell development.
IL-7
146
T-Cell Differentiation stages:
1. Double-Negative Stage
2. Double-Positive Stage
3. Mature T-Cells
147
Rearrangement of the genes that code for the antigen receptor known as TCR begins at this stage.
Double-Negative Stage
148
Antigen receptor in Double-Negative Stage is called?
T-cell receptor complex (TCR)
149
Beta-Chain rearrangement in Double-Negative Stage: Signaling by the β chain also triggers the thymocyte to become _____ and _____.
CD4-positive (CD4+) and CD8-positive (CD8+) cells
150
The complex that serves as the main part of the T-cell antigen receptor.
CD3
151
Early thymocytes lack?
CD4-positive (CD4+) and CD8-positive (CD8+) cells
152
CD3 consists of ___________, six of which are common to all T cells.
eight noncovalently associated chains
153
Six chains common to all T cells.
* alpha and beta have constant and variable regions
* epsilon
* gamma
* zeta
* delta
154
The two chains associated in the T-cell receptor that recognizes antigens?
alpha and beta chains
155
Rearrangement of alpha chain takes place in what stage of T-cell development?
Double-Positive Stage
156
Two selection process in Double-Positive Stage?
* Positive selection
* Negative selection
157
When does the Double-Positive Stage start?
if there is complete expression of the CD3TCR complex
158
When the CD3-αβ receptor complex (TCR) is expressed on the cell surface, a _______________ takes place that allows only double positive cells with functional TCR receptors to survive.
positive selection process
159
In the positive selection process of the double-positive stage, T cells must recognize foreign antigen in association with ____________.
class I or class II MHC molecules
160
True or false: Any thymocytes that are unable to recognize self-MHC antigens die without leaving the thymus.
True
161
Takes place among the surviving double-positive T cells.
Negative selection
162
In negative selection of the double-positive stage, strong reactions with self-peptides send a signal to delete the developing T cell by means of ________, or programmed cell death.
apoptosis
163
The negative selection process is very rigorous, because only _________ of the double-positive thymocytes in the cortex survive.
1 to 3 percent
164
In mature T-cells, CD4+ T cells recognize antigen along with __________.
MHC class II protein
165
T helper cells consist of two subsets?
Th1 and Th2
166
TH1 is associated with?
gamma or type 2 Interferon and Tumor Necrosis Factor-beta
167
Role of TH2?
help B cells to produce antibodies against extracellular pathogens and produce interleukins 4, 5, 10, and 13
168
In mature T-cells, CD8+ T cells interact with antigen and _________.
MHC class I proteins
169
1/3 of the total T-cell population is associated with what cell?
CD8+
170
Activated T lymphocytes express receptors for_____, just as activated B cells do.
IL-2
171
Receptor for IL-2?
CD 25
172
Third major subclass CD4+ T-Cell population?
T-Regulatory Cells
173
T-Regulatory Cells possess which CD markers?
* CD4
* CD25
174
T-Regulatory Cells comprise approximately _________ percent of all CD4-positive T cells.
5 to 10
175
T-Regulatory Cells produce which cytokines?
IL-10 and transforming growth factor-beta
176
Third population lymphocytes?
Natural killer cells
177
5-10% circulating lymphocyte in the PB?
Natural killer cells
178
These lymphocytes are generally larger than T cells and B cells.
Natural killer cells
179
Characteristics of NK cells?
* 15 μm in diameter
* kidney-shaped nuclei with condensed chromatin
* prominent nucleoli
* higher cytoplasmic-nuclear ratio
* cytoplasm contains a number of azurophilic granules
180
They represent the first line of defense against virally infected and tumor cells.
Natural killer cells
181
Diseased and cancerous cells tend to lose their ability to produce?
MHC proteins
182
A second method of destroying target cells.
ADCC/Antibody-Dependent Cellular Cytotoxicity
183
They recognize and lyse antibody-coated cells through a process called?
ADCC/Antibody-Dependent Cellular Cytotoxicity
184
Type of WBC that is considered as ADCC?
Eosinophil
185
Cells coated with IgM are not subject to ADCC because?
IgM has no available Fc region
186
Primarily, _____ is the antibody responsible for ADCC.
IgG
187
A technique to separate mononuclear cells from other cells.
Density Gradient Centrifugation with Ficoll-Hypaque
188
The specific gravity for Density Gradient Centrifugation with Ficoll-Hypaque varies depending on the manufacturer, but ranges from?
1.077 to 1.114
189
Centrifugation for Density Gradient Centrifugation with Ficoll-Hypaque produces 3 distinct layers?
* Plasma
* Mononuclear cells
* RBC and Granulocytes
190
2 types of Cell flow cytometry?
1. Forward Light Scatter
2. Side Light Scatter
191
Forward Light Scatter identifies?
Cell Size
192
Side Light Scatter identifies?
Cellular Granularity
193
Lymphocytes are separated from whole blood and then mixed with a suspension of sheep red blood cells is performed in what test?
Rosette test/technique
194
E-rosette is in line with?
T cells
195
EAC/Erythrocyte Antibody Complement rosette is involved with?
B cells
196
Laboratory Techniques to Quantify and Identify Lymphocytes?
1. Density Gradient Centrifugation with Ficoll-Hypaque
2. Cell flow cytometry
3. Immunofluorescence microscopy
4. Rosette test/technique
197
An automated system for identifying cells based on the scattering of light as cells flow in single file through a laser beam.
Cell Flow Cytometry
198
In Cell Flow Cytometry, _____________ are used to screen of subpopulation of T and B cells.
Fluorescent antibodies
199
Components of Cell Flow Cytometry?
* Sample delivery system
* A laser for cell illumination
* Photodetectors for signal detection
* Computer based management system
200
2 types of IFA (Immunofluorescence Assay)?
1. Direct Immunofluorescence
2. Indirect Immunofluorescence
201
Uses monoclonal antibodies with a fluorescent tag fluorescein and phycoerythrin (490nm) rhodamine (545 nm).
Direct Immunofluorescence
202
Uses unlabeled antibody that first combines with the antigen by itself and a second antibody that is complexed with a dye.
Indirect Immunofluorescence
203
phycoerythrin nanometers?
490nm
204
rhodamine nanometers?
545 nm
