Immune System Flashcards
(121 cards)
1
Q
what are the functions of the immune system
A
- surveillance of the body
- recognition of foreign material
-destruction of entities deemed to be foreign
2
Q
what is innate/natural/non-specific immunity stimulated by
A
-structures common to groups of related microbes
-cannot distinguish between fine differences of foreign substances
3
Q
what is acquired immunity
A
- very specific response to a distinct macromolecule
- remembers macromolecules and response more vigorously the second exposure
4
Q
what is the relationship between the innate immune system and acquire immunity
A
influence each other
5
Q
what are the agranulocytes
A
-monocytes/macrophages
-lymphocytes
6
Q
what are the granulocytes
A
-neutrophils
-eosinophils
-basophils
7
Q
what is the order of abundance of blood cells
A
- neutrophils
- lymphocytes
-monocytes
-eosinophils
-basophils
8
Q
describe the leukocytes compared to RBCs
A
all are nucleated and are larger and less numerous
9
Q
describe all granulocytes
A
polymorphonuclear
10
Q
what is the function of innate immunity
A
-protective
- neutralizes harmful agents
-removes dead tissue
- initiates the tissue repair process
11
Q
what do damaged cells in innate immunity release and do
A
release inflammatory mediators which stimulate the inflammatory process but they can also injure normal tissue
12
Q
where do mediators of the innate immune system act
A
locally and systemically
13
Q
what are the cardinal signs of acute inflammation
A
-rubor
- calor (heat)
- dolor (pain)
- swelling
-loss of function
- edema
14
Q
what is activated in the complement system
A
C3a and C5a
15
Q
what do C3a, C5a, histamine, bradykinin, and serotonin cause
A
-fluid leakage as exudate
-vasodilation
16
Q
what do neutrophils cause
A
-chemokines -> ingestion of bacteria -> cytokine secretion -> recruitment of macrophages and lymphocytes -> selectins -> endothelial stickiness and integrins
17
Q
what is phagocytosis an essential part of
A
inflammation and acquired immunity
18
Q
what particles do cells engulf
A
non-self or damaged particles
19
Q
what is phagocytosis of innate immunity accomplished by
A
mostly neutrophils and macrophages
20
Q
what is the difference in ability to phagocytize between macrophages and neutrophils
A
macrophages can phagocytize for more and larger material and are already in the tissue
21
Q
how does a phagocyte recognize its “meal”
A
-phagocytes contain toll-like receptors (TLRs) that can recognize generic PAMPS and DAMPS
- rough surface
22
Q
what should native substances have on their surface to repel phagocytes
A
protein coats
23
Q
how is a cell marked for phagocytosis
A
a target will have an immunoglobulin/antibody attached to it
24
Q
what part of the immune system secretes Interferons
A
innate immunity
25
what secretes INF and what does it do
-virally infected cell secretes it
- causes uninfected cells to produce enzymes that inhibit viral replication which prevents the spread of the virus to neighboring cells
26
what does the complement system consist of
30 distinct components that are in plasma in an inactive form and must be cleaved to become active
27
what is the complement system activated by
substances on the surface of microbes
28
what does the cascade of reactions in the complement system lead to
- enhancement of inflammation
-opsonization of pathogens
- formation of a MAC that lyses pathogens
29
what immune system is the complement system activated by
both innate and acquired
30
what cell types require activation in acquired immunity
B and T lymphocytes
31
what type of immunity are B cells involved in
humoral
32
what type of immunity are T cells involved in
cell-mediated
33
what are helper T lymphocytes also called
CD4+
34
what are cytotoxic T lymphocytes also called
CD8+
35
what are antigens
molecules capable of inducing an acquired immune response by binding to B cell and T cell receptors and the production of antibodies against them
36
what type of molecule are antigens
surface peptides or polysaccharides
37
what is an epitope
molecular group on the antigen that is recognized by the immune system
38
what do antigen presenting cells do (APCs)
present antigens on their surface via MHC class II molecules
39
what do APCs bind to and activate
T helper cells -CD4
40
what do T helper cells (CD4) activate
humoral and cell-mediated immunity in acquired immunity
41
what are the antigen presenting cells and what do they do
- macrophages: ingest the pathogen and induce an inflammatory response if appropriate
-lymphocytes
- dendritic cells: ingest the antigen and migrate to the nearest lymphoid organ
42
describe cell mediated immunity
activated T cells (NK cells, Cytotoxic T, CD8) result in killing of infected cells and stimulation of phagocytosis of bacteria and fungi
43
describe humoral immunity
activated B cells develop into plasma cells that secrete immunoglobulins. the antibodies neutralize toxins and viruses and enhance phagocytosis of bacteria
44
where do activated T and B cells initiate a response
in secondary lymphoid tissues
45
what do macrophages kill
bacteria
46
what do NK cells kill
virus infected cells and tumor cells
47
what do cytotoxic T cells kill
tumor cells and virus infected cells
48
what do T and B lymphocytes do upon activation
replicate a lot into clones and are secreted into the lymphatic circulation. then they cycle through the blood, tissue, and back to the lymph working as effector cells to eliminate the antigen
49
what causes Naive T cells to be made into T cell clones
cytokines
50
what are plasma cells
B cells that secrete antibodies
51
where are MHC class II cells found and what are they involved in
found on antigen presenting cells such as macrophages, dendritic cells and are involved in presenting antigens to T helper cells for cell mediated immunity
52
what do MHC class 1 do
code for markers that display unique characteristics of self and foreign antigens when the cell is infected
53
what does the interaction between MHC class II and T helper cell cause
activation of the T cell and creation of T cell clones
54
what does the interaction between MHC class I and cytotoxic T cell cause
destruction of an infected cell when it presents a foreign antigen
55
what are the actions of T lymphocytes
-growth and proliferation of cytotoxic and suppressor T lymphocytes
-growth and proliferation of B lymphocytes
-stimulates activation of more T helper cells
- activation of macrophage system
56
what does activation of the macrophage system cause
-attract and slow/stop macrophage migration away from inflamed regions
- stimulate more efficient phagocytosis
57
what cells have MHC Class I on their surface
all nucleated cells
58
what do cytotoxic T cells do after binding antigens
-secrete perforin molecules that punch holes in the membrane of the target which causes the cell to swell and lyse
- release of granzymes into the target through perforin channels that stimulate apoptosis
59
what do cytotoxic cells do after secreting substances
they can unbind and move to another cell
60
what do suppressor T cells do
-suppress functions of cytotoxic and helper T cells
-secrete inhibitory cytokines
- limit the immune systems ability to attack ones own tissues and add to immune tolerance
61
what are B cells activated by
intact antigens and activated T helper cells
62
what do B cells look like when activated
they enlarge and look like lymphoblasts
63
what can B cells differentiate into
plasmablasts which become plasma cells
64
where are immunoglobulins secreted
into the lymph and carried into the blood for circulation
65
what is the FAB region
the antigen binding region of the immunoglobulin
66
what does the Fc region of the immunoglobulin determine and what is it also called
-AKA constant portion
- determines diffusivity through membranes, complement attachment, and other biological properties
67
what does the heavy chain determine
Ig classification
68
what receptors do phagocytes contain and what does this cause
Fc receptors so antibody binding to an antigen leads to enhanced phagocytosis
69
what immunoglobulin is most abundant in the blood
IgG
70
what are the immunoglobulins
-IgG
- IgE
-IgA
-IgM
- IgD
71
what does IgG do
-complement activation
-opsonizes bacteria
-neutralizes bacterial toxins and viruses
-antibody dependent cell mediated cytotoxicity mediated by NK cells and macrophages
72
what is the primary antibody in the secondary response
IgG
73
what type of reactions is mediated by IgG
type 2 and type 3 hypersensitivity reactions
74
what type of reactions are mediated by IgE
type 1 hypersenstivity reactions
75
what does IgE do
defends against parasitic infections
76
what cells are activated by IgE
basophils, mast cells and eosinophils
77
where is IgA synthesized
by plasma cells in exocrine glands
78
what is the most abundant Ig in the body
IgA
79
what type of immunity does IgA mediate
mucosal immunity and neonatal immunity
80
what Ig is the most potent activator of complement
IgM
81
what is the largest Ig
IgM
82
what is the first Ig produced in response to an antigen
IgM
83
what is IgM secreted as
membrane bound as a monomer but can also be a pentamer
84
what do B cells begin to express on their surface when they reach maturity
IgM and IgD
85
where is IgD located and what does it do
-membrane bound, receptor on B lymphocytes surface
-aids in recognition by B lymphocytes
86
what happens to B cells after antigen activation and why
-they undergo antibody class switching to produce IgG, IgA, or IgE antibodies to allow daughter cells from the same activated B cell to produce different types of abs
87
describe the secondary immune response compared to the primary response
it is faster, stronger, and longer
88
what does binding of antigen binding site of an antibody with an antigen cause
-neutralization
-agglutination
-precipitation
89
what does exposed Fc portion following antigen binding by antibody cause
-complement fixation
- opsonization
-activation of NK cells
90
what immunoglobulins activate the complemetn system
IgM and IgG
91
what is tolerance
immunologic unresponsiveness to self antigens
92
where is tolerance seen
- clonal deletion occurs within the fetal thymus and bone marrow - central tolerance
- clonal anergy is when cells that are self antigenic become non functional -peripheral tolerance
93
what happens when self tolerance fails
autoimmune disease
94
what percentage of autoimmune diseases occur in women
90%
95
what are the theories for why immune tolerance fails
-failrue of regulation of self reactive lymphocytes
-exposure of T lymphocytes to antigens previously sequestered from the immune system
- molecular mimicry by invading pathogens
- modification of self antigens
-inappropriate expression of class II MHC molecules
96
where does molecular mimicry occur
in rheumatic fever where strep mutans resembles a portion of cardiac myosin
97
what are some autoimmune diseases we have learned about and what is targeted
- rheumatic fever
-myasthenia gravis- Ach disorder
- lupus- targets red and white blood cells, platelets, etc
- Rheumatoid arthritis
- sjogrens syndrome
- multiple sclerosis - targets myelin sheath
- type 1 diabetes
-graves disease
98
what happens in the type 1 reaction
-IgE antibody is induced
-binds to mast cells and basophils
- the allergen cross links bound IgE and induces degranulation of mast cells and basophils
99
what happens in the type 2 reaction
antigens on a cell surface combine with antibody; this leads to complement mediate lysis
100
what happens in the type 3 reaction
antigen antibody immune complexes are deposited in tissues, complement is activated and polymorphonuclear cells are attracted to the site. they released lysosomal enzymes causing tissue damage
101
what happens in the type 4 reaction
helper T lymphocytes sensitized by an antigen release lymphokines upon second contact with the same antigen. the lymphokines induce inflammation and activate macrophages, which in turn release various mediators
102
where are mast cells and basophils most concentrated
in the lung, skin and GI tract
103
what does the release of secretory products from mast cell granules (histamine) do
increases vascular permeability, vasodilation, bronchial and visceral smooth muscle contraction, salivary and bronchial secretions and inflammation
104
what is the effect of a type 1 reaction do to respiratory resistance and BP
increases respiratory resistance and decreases BP
105
why can type 1 reactions be life threatening
bronchoconstriction and vasodilation causing hypotension and anaphalyxis
106
how long does a type 1 rxn take
within minutes
107
how long can IgE remain in the tissues
for years
108
what happens in type 1 hypersensitivity reactions if re exposed
the allergen contract the mast cells and stimulate degranulation and person can react immediately upon exposure
109
what is the late phase reaction in type 1 hypersensitivty reactions
-inflammatory infiltration of eosinophils, basophils, neutrophils and lymphocytes 2-4 hours after degranulation of mast cells and basophils
110
what are the treatment/preventative options for type 1 allergic responses
-avoid the allergen
-take drugs that block the action of lymphocytes, mast cells or chemical mediators
-undergo densitization therapy
111
what does desensitization therapy consist of
- controlled injections of the antigen
-works by producing IgG antibodies rather than IgE
112
what are IgG antibodies considered to be
blocking antibodies
113
if you are allergic what type of antibodies do you produce in response to environmental allergens
IgE
114
what type of things trigger IgE antibody production
-hay fever
-asthma
-drug insensitivity such as penicillin
-food allergies
- urticaria
-anaphylaxis
115
what are the most common food allergies
peanuts
-fish
-cow milk
-eggs
-shellfish
-soybeans
116
what are type 4 hypersensitivity reactions mediated y
T cells
117
what happens in a type 4 hypersensitivity reaction
-helper and cytotoxic T cells are activated and produce a cell mediated immune reaction which stimulates macrophage recruitment and inflammation
118
how long does it take for type 4 hypersensitivity reaction to kick in
delayed 1-2 days
119
where are type 4 hypersensitivity reactions restricted to
tissue area exposed to the pathogen
120
what is a common example of a type 4 hypersensitivity reaction
contact dermatitis
121
how do helper t cells and cytotoxic T cells respond upon repeat exposure in type 4 hypersensitivity reactions
increased response on repeated exposures
