Immunology Part 1 Flashcards
1
Q
the study of the physiological mechanisms that humans and other animals use to defend their bodies from invasions by other organisms
A
immunology
2
Q
cells within the human body that are dedicated to defense from foreign invaders
A
immune system
3
Q
There are numerous species of ___ colonize the human body in large numbers and rarely produce symptoms of __
A
microorganisms
disease
4
Q
any organism with the potential to cause disease
A
pathogen
5
Q
What are the four kind of pathogens
A
bacteria, viruses, fungi, parasites
6
Q
What are the different types of parasites?
A
unicellular protozoa, multicellular invertebrates, worms
7
Q
single-celled organisms without a nucleus
A
bacteria ex. E. coli
8
Q
thread-like particles that reproduce by taking over living cells
A
Viruses ex. herpes simplex
9
Q
simple organisms, including mushrooms and yeasts, that grow as single cells or thread like filaments
A
Fungi ex. death cap mushroom
10
Q
single-celled organism with a nucleus
A
Protozoa ex. Giardia lamblia
11
Q
What are the different types of foreign invaders that can affect the body?
A
bacteria, viruses, fungi, parasites, microbes
12
Q
What are the four functions of the immune system?
A
- prevent entry of foreign cells into the body
- eliminate foreign agents that have entered the body
- eliminate abnormal self cells (cells become abnormal due to age, infection, intracellular pathogen, transformed/ cancer)
- Some immune cells are also involved the removal of dead cells or tissues and in the generation of new blood vessels
13
Q
microorganisms (bacteria, viruses, yeasts, fungi, parasites) and the products of these organisms (endotoxin/ exotoxin).. foods, pollen, chemical, drugs
A
Foreign agents
14
Q
proteins secreted by certain species of bacteria which diffuse in the surrounding medium
A
exotoxin
15
Q
usually heat stable lipopolysaccharide-protein complexes which form structural components of the cell wall of gram negative bacteria
A
endotoxin
16
Q
When are endotoxins released?
A
during cell lysis or death of bacteria
17
Q
What are the external barriers of the immune system?
A
physical, chemical, and microbiologic
18
Q
What are the physical Barriers of the immune system?
A
skin - first defense
19
Q
What are the chemical barriers of the immune system?
A
- lysozyme in tears and saliva for antibacterial substance secreted from mucosa
- cilia in the lungs participate in continual cleansing of unwanted material breathed in acidic environment in the stomach, vagina or skin deters microorganisms
20
Q
commensal microorganisms (gut, vagina, etc)
A
Microbiolgic Barriers
Good Bacteria
21
Q
involved in the destruction and elimination of foreign agents destruction and elimination of foreign agents that have made it through the external barrier or altered self cells
A
Systemic defense
22
Q
What are the two components of systemic defense?
A
cellular and humoral component
23
Q
cells of innate immunity (phagocytosis), cells of acquired immunity (specialized cells such as T cells)
A
cellular component
24
Q
antibodies, complement proteins, antimicrobial proteins
A
humoral component
25
antimicrobial peptides secreted by epthelial sufaces
defensins
26
What is mechanism of action of defensins?
to kill the bacteria, fungi, and enveloped viruses by disruptinf their membranes
27
What is mechanism to prevent defensins from disrupting human cells?
they are synthesized as part of a longer, inactive polypeptide and function poorly unless they are lower ionic concentrations of sweat, tears, or the lumen of the gut to become active
28
Epithelia is coated with what?
a flora of nonpathogenic micoroorganisms that compete with pathogens
29
microbial species that live in the healthy human gut
commensal species
30
What is the mechanism of action for microbiologic barriers?
* inhibit the colonization of pathogens and enhance human nutrition by further processing digested food and making vitamins
* ex. when a pt takes antibiotics, the nonpathogenic flora is killed together with the pathogens that caused the disease, then the body is recolonized by microorganisms
31
Explain how the External barriers of the body react to C. Diff
32
33
What are the two branches of the immune system?
innate immunity and adaptive (acquired) immunity
34
What is innate immunity?
immunity we are born with, includes barriers, fast, no memory
35
What is adaptive/ acquired immunity?
specific, diverse, slow, can develop immunologic memory, can be passive or active
36
What are the two types of adaptive immunity?
passive and active
37
refers to the situation when the person recieves the antibodies form another source.
passive immunity
38
What are the ways passive immunity can be acquired?
placenta, colostrum (breastfeeding), genetically engineered antibodies (vaccine)
39
refers to the situation when the individual is exposed to an antigen (naturally or through immunization) indviduals build up defense (antibodies) against the antigen
active immunity
40
Innate Immunity Response:
- Determined by?
- time?
- memory?
- determined entirely by the genes a person inherits from their parents
- fast, **within minutes**, causing **fevers**
- **No memory**
41
What are the steps to the response of the innate immune system?
1. recoginition of a pathogen, recruitment of effector cells that **engulf bacteria, kill virus **infected cells, or attack protoxoan parasites and a battery of serum proteins
2. serum proteins of the complement system are **activated in the presence of a pathogen** and form a covalent bond and the pathogen gets marked as dangerous
3. the soluble complement fragment summons a **phagocytic WBC** to the site of the complement activation
4. effector cell has a surface receptor that binds to the complement fragment attached to pathogen
5. receptor and boud ligand are taken into the cell by endocytosis and further to the **phagosome** , where it is destroyed
42
What are the components of the complement system?
43
The cells of the innate system originate from where?
pluripotent hematopoietic stem cells
44
The pluripotent hematopoietic stem cells derive what?
leukocytes, erthyrocytes, and megakaryocytes
45
the development by which hematopoietic stem cells give rise to hematopoietic cells
hematopoiesis
46
Where is the development of blood cells in:
1. early embryo?
2. 3-7th week of life?
3. 4-5th week of life?
4. Adult?
1. yolk sac to liver
2. spleen
3. bone marrow
4. bone marrow of skull, ribs, sternum, vertebral column, pelvis, and femurs
47
What are the two cell lineages of hematopoietic stem cells?
myeloid (innate)
lymphoid (adaptive)
48
Draw the breakdown of the immune system cells
49
prominent cytoplasmic granules, which contain reactive substances that kill microorganisms and enhance inflammation
granulocytes
50
Neutrophils:
* Abundance?
* lethal? yes or no?
* specializes in?
* arrives when?
* half life?
* What does it release?
* Does it need o2?
- most abundant
- lethal
- **phagocytes**
- first cell to arrive
- 6 hour half life
- relases granules causing damage to host tissue, die at the site of infection, forming **pus**
- anaerobic and aerobic
51
Eosinophils:
* Abundance? Where?
* Defends against?
* Increased in?
- second most abundant in mucosa of GI tract, where they defend against parasites, and in the respiratory and urinary tract
- defends against helminth worms and other parasites
- increased in allergic diseases such as asthma and other respiratory and gastrointestinal diseases
52
Basophils:
* Abundance?
* Releases?
* participates in?
- least abundant
- releases histamines and other inflammatory mediators when activated by binding of spefici antigens to IgF molecules
- participates in the immediate release-type hypersensitivity (allergic) reactions
53
Mast Cell:
* Lives where?
* contributes to? how?
* releases?
* important for?
- lives in all connective tisse
- activation and degranulation of this cell at sites of infection is major contributor to inflammation
- releases granules (histamines)
- part of allergic response
54
Monocytes:
* Circulate where?
* bigger than what?
* have a distinct?
* how do cells look?
* mature as?
- leukocytes that circulate in the blood
- bigger that granulocytes
- distinct nucleus
- cells look the same
- travel in the blood to tissue where they mature to macrophages
55
Macrophages:
* Equipped for?
* provide?
* secrete? Recruit?
* First phagocytic cell to do what?
- equipped for phagocytosis, scavengers, commanders
- provide intelligence to other cells for response to infection
- secrete cytokines that recruit neutrophils and other leukocytes
- first phagocytic cell to sense an invading organism
56
What are the functions of monocytes?
57
Dendritic cells:
* location?
* distinction?
* similar to?
* function?
- lives in the bodys tissue
- have a distinct star shaped morphology
- similar to macrophages
- act as cellular messengers to initiate the adaptive immune response by leaving the infectd tissue with a cargo of degraded and intact pathogens to bring to one of the lymphoid organs
58
lable the cell stains
59
lable the blood cells
60
What are the unique components of:
-lymphocytes
-monocytes
-Neutrophils
- lymphocytes are fille with the nucleus
- monocytes are the largest of the white cells and have variable shape nuclei
- neutrophil is pale and has a multilobed nucleus that helps squeeze through the small gaps in capillaries when called upon to fight bacterial infections
61
Lable the WBC
62
has both a cell of innate immunity and two cells of the adaptive immunity
lymphoid lineage
63
Large Granular lymphocytes:
* also known as?
* function
* importance?
* mechanism?
- Natural Killer Cells
- effector cells of innate immunity
- important in the dense against viruses
- work by entering infected tissue, kill virus infected cells, and secrete cytokines that impede viral replication in infected cells
64
innate immune response works to slow the spread of infection while it calls on?
lymphocytes which activate adaptive immunity
65
What is main difference between adaptive and innate immunity?
adaptive immunity uses cell surface receptors, which are used by lymphocytes
66
What is the mechanism of adaptive immunity?
1. during development each lymphocyte is programmed to make a single species of cell surface antigen receptors
2. the population of circulating lymphocytes embraces many receptor species which enables all possible pathogens to be recognized
3. during infection only lymphocytes bearing receptors recognize the pathogen participate in the adaptive response and their numbers expand and mature to produce more cells
4. this makes adaptive response slow
3. this also allows to** long term immunological memory**, which allows cells to produce stronger and faster adaptive responses when they have a future encouter
67
Adaptive long term memory differs how?
Some pathogens like measles, one full blown infection can provide immunity for decades. Influenza effect is more short lived as it changes on a yearly basis to escape the acquired immunity in human hosts
68
cells responsible for adaptive immunity. They are small because they circulate around in their immature form that is functionally inactive. Recognition of a pathogen drives a process of lymphocyte selection, growth, and differentiation
small lymphocytes
69
What is the difference between B lymphocytes and T lymphocytes?
the receptors: T cells have CD4+
B cells have CD8+
70
71
(5-15% of circulating lymphocytes) surface receptors for pathogens are immunoglobulins, express a single type of immunoglobulin
B cells
72
(85-95% of circulating lymphocytes)T cell receptors, express a single type of T-cell receptor
T cells
73
Where do lymphocytes congregate?
congregate in lymphoid tissues/lymphoid organs
* Ex: Bone marrow, thymus, spleen, adenoids, tonsils, appendix, lymph nodes
74
Where is lymphoid tissue found?
found lining the mucosal surfaces of the respiratory, gastrointestinal, and urogenital tracts
74
What are two types of lymphoid tissue?
Locations/
- primary/ central lymphoid tissue
bone marrow, thymus
- secoundary/ peripheral
lymph node, spleen (serves as a filter for the blood to remove damaged or old RBC)
75
where lymphocytes develop and mature to the stage at which they are able to respond to a pathogen
Primary/ central lymphoid tissue
76
where mature lymphocytes become stimulated to respond to invading pathogens
Secondary/ peripheral
77
B Cells:
* origin?
* mature?
Originates in the bone marrow and completes maturation in the bone marrow before entering circulation
78
T Cells:
* Origin?
* Mature?
Originate in the bone marrow, but leave in their immature stage and migrate in the blood to the thymus (adults in lymph nodes), where they complete maturation
79
Why do immature lymphocytes get destroyed?
majority of immature lymphocytes are destroyed because they fail to develop immunoglobulins of T cell receptors. The small fraction of immature B and T cells that successfully complete development depart from the primary lymphoid organs and enter the circulation
80
What is the mechanism of the secoundary/ peripheral lymphoid tissue?
1. pathogens are carried by the lymphatics to the nearest lymph nodes
2. along this route are dendritic cells that have been activaed by the infection and are carrying pathogens and their components
3. Lymph flow is sluggish (no dedicated pump), do have valves to prevent backwards flow. If it gets interrupted can develop lymphedema
81
lie at the junction of the anastomosing network of lymphatic vessels which collect the plasma that continually leaks out of the blood vessels and forms the extracellular fluid
Lymph Nodee
82
Lymphatics return extracellular fluid to th blood through____ which empties into the ____ in the neck
thoracic duct
left subclavian vein
83
What is pathway for mature lymphocytes?
leave the primary lymphoid tissue and enter the blood stream, then secondary lymph tissue, then lymphatics, and back to the blood- **recirculation of lymphocytes**
84
Lymphocytes enter and leave through what?
spleen
85
Lable the following
86
In the lymph node, T cells move into the T cell areas and forms transient interactions with? after binding the T cells divide and differntiate into?
dendritic cells
- Helper T cells (CD4) and Cytotoxic T cell (CD8)
87
stay in the lymph node and provide soluble proteins and intercellular contacts that drive the differntiation of B cells possessing immunoglobulin receptors that bind that pathogen
Helper T cells (CD4)
88
these cells kill infected cells with viruses or other intracellular pathogens
Cytotoxic T cell (CD8)
89
short peptides that have assembled into a complex with a membrane glycoprotein
Major histocompatibility complex molecule (MHC)
90
B cell antigens bind directly as ____ while T cell antigens must be ____
whole native structures
broken down into peptides
91
Explain the assembly of a peptide
1. MHC complex takes place in the cell where the antigen was formed
2. complex then transported to cell surface where it is accessible to T cell receptors –
3. OVERALL: essentially they present antigens to T cells so the peptide(antigen):MHC complex is referred to as antigen presenting cells
92
What can only bind short peptides that have been assembled into a complex with a membrane glycoprotein?
T cell receptors
93
Cells that are expressing MHC complexes can present antigens to T helper cells or cytotoxic cells
Antigen presenting cells
94
What are the antigen presenting cells?
- langerhans cells in skin
- dendritic cells
- macrophages
- B cells
95
MHC Class I molecules:
* Present?
* Derived from?
* replicate where?
* Examples?
* Location?
-Present peptide antigens
-derived from pathogens
-replicate intracellularly
-viruses and some bacteria and whose proteins are present in the cytosol of the infected cell
-on almost all cell types
96
MHC Class I molecules present peptides by? and distinguish by?
Present peptides to** cytotoxic T cells **that function by killing infected cells and distinguished by the presence of the **CD8 glycoprotein** on their surfaces
97
MHC Class II Molecules are obtained from?
present peptides obtained from pathogens and their products that are present in the extracellular milieu and have been taken up into the endocytic vesicles of phagocytic cells
98
MHC II Class molecules of dendritic cells present peptides to what?distinguished by?
helper T cells distinguished by the presence of the CD4 glycoprotein on their surface
99
Where are MHC Class II molecules present?
on only a few cell types
100
glycoproteins found on B-cell membranes or secreted by plasma cells
antibodies
101
Where are immunoglobulins expressed?
the surface of B cells where the bind pathogens
102
What do antibodies bind to? making them interact with?
- bind to bacterial cells and intact viral particles in the extracellular spaces, **targeting them for phagocytosis**
- interact with intact components of the pathogen surface such as glycoproteins and proteoglycans
103
any molecule, macromolecule, virus particle, or cell that contains a structure recognized and bound by an immunoglobulin or T cell receptor
antigen
104
the particular part of the antigen bound by the immunoglobulin or T cell receptor is know as the antigenic determinant
epitope
105
B cells and T cells receptors have specifity for what?
the antigen they bind
106
What are the 5 classes or isotypes of antibodies
107
IgA:
* Made where?
* Transported where?
* Binds where?
* main function?
* found where?
- made in the lymphoid tissues underlying mucosa
- transported across the mucosal epithelium
- bind extracellular pathogens and their toxins on the mucosal surfaces
- Main Function: **first defense **for mucosal surfaces such as the intestines, nose, and lungs.
- blood, saliva, and gastric juices
108
IgG:
* Facilitates?
* Binds with?
* produces what?
* Provides what type of protection?
- facilitate the engulfment and destruction of extracellular microorganisms and toxins by phagocytes/ fighting infections from bacteria and viruses
- cell receptors of Neutrophils and macrophages
- A combination of IgG antibody and complement produces the greatest simulation of phagocytosis because both macrophage receptors for IgG and complement participate in the process
- provides long term protection because it persists for months and years after the antigen that has triggered their production
109
IgM:
* Secreted when?
* part of what immune response?
* activates what?
* antigen receptor on what?
* located where?
* provide what kind of protection?
- first antibody to be secretd in the immune respose
- **part of the primary immune response**
- **best at activating the compliment**
- antigen receptor on circulating B cells
- antibodies found in the blood and lymph fluids
- provide short term protection
110
IgE:
* Binds with?
* important role in what
- underdevelped vs developed?
- bind tightly to receptors on the surface of mast cells
- In **under developed** countries IgE has large role in response to worms and parasites due to strong inflammatory reaction
- In **developed countries**, IgE is most often encountered as the antibody in unwanted allergic reactions
111
What occurs to antibodies after immunization or infection?
naïve B cells become activated and can switch from expressing IgM and IgD on their surface to expressing IgG, IgE or IgA
112
What is the mechanism of neutralization in antibodies?
antibodies neutralize pathogens or their toxic products by binding to them and thus preventing them to enter cells and subsequent their infection. This mechanism is critical for protection against bacterial toxins and also pathogens such as viruses
113
What occurs in the mechanism of oponization in antibodies?
antibodies enable phagocytosis for ingesting and destroying the extracellular bacterium. The phagocytes recognize the Fc region (the base of the ”Y”) of the antibodies coating the pathogen and foreign particles
114
activation of several plasma protiens
complement system
115
Why are immunoglobulins clinically important?
- part of our immunologic memory
- used in laboratory testing
- used in treatment/ therapy
116
What does lab testing for immunoglobulins help with?
-Help diagnose and monitor a variety of conditions that may cause abnormal levels of IgM, IgG, and/or IgA, such as auto immune disorders (RA or lupus), cancer, and acute and chronic infections
117
reflects a collective exposure of the donor population to their environment and can be expected to contain an antibody repertoire of multiple specificities against a broad spectrum of infectious agents (bacterial, viral, and others), and self-antigens
intravenous immunoglobulins
118
What plays a pivotal role in humoral adaptive immunity?
immunoglobulins
119
When should IVIG therapy be used?
-As a replacement therapy in immunodeficiencies.
-For immunomodulatory and anti-inflammatory therapy, (a)** Immunomodulation** in hematological and organ-specific autoimmune disorders (b) **Anti-inflammatory **in rheumatic inflammatory conditions, infectious and neurological disorder
-As a hyperimmune therapy against specific infectious agents.
