Cell Mediated Immunity Flashcards
(56 cards)
1
Q
what percent of peripheral blood T cells are CD4+
A
- 65%
2
Q
function of T helper lymphocytes
A
- secrete cytokines
- induces activation of B-lymphocytes and other cells
3
Q
function of regulatory T cells
A
- suppress T lymphocyte proliferation toward the end of an immune reaction
- suppress auto reactive T cells that have escaped negative selection
4
Q
what percent of peripheral blood T cells are CD8?
A
- 35%
5
Q
function of CTLs
A
- release cytolytic substances such as perforin, granzyme, and ligands directly into target cells
- promotes apoptotic cell death
- virally infected cells and tumor cells
6
Q
memory T cells
A
- antigen-specific T cells that persist long-term after an infection has resolved
7
Q
memory T cells upon re-exposure to cognate antigen
A
- quickly expand to a large number of effector T cells
8
Q
memory cell types
A
- CD4 or CD8
9
Q
stages of t lymphocyte maturation
A
- stem cell
- Pro-T
- Pre-T
- Double Positive
- Single positive immature
- naive mature
10
Q
thymocytes that originate from the bone marrow
A
- lack expression of the T cell receptor
11
Q
double negative thymocytes
A
- do not express CD4 or CD8
- up regulate expression of cell surface glycoproteins followed by TCR gene arrangement
12
Q
where does maturation of T cells occur?
A
- in the thymus
13
Q
two processed of thymic education
A
- MHC restriction
- self tolerance
14
Q
MHC restriction
A
- CORTICAL thymic epithelial cells asks developing T-cells if it recognizes the self MHC molecule it is expression
- correct answer is yes
- positive selection
15
Q
positive selection and affinity
A
- want low to moderate affinity
16
Q
cells that connect bind and recognize self-MHC or bind with too low an affinity
A
- undergo apoptosis
17
Q
self tolerance
A
- MEDULLA thymic epithelial cells asks developing T cells if it recognizes self peptides on MHC molecules
- correct answer is no
- negative selection
18
Q
negative selection and affinity
A
- thymocytes that bind self peptides with high affinity
- deletes possible auto-reactive T cells
19
Q
naive T cells
A
- single positive thymocytes that leave in a resting phenotype
20
Q
activation of naive T cells
A
- single positive T cells
- go from lymph node to blood seeking encounters with pathogen
- TCR binds target peptide
- receives signal to become activated cell
21
Q
MHC class I displays
A
- fragments of proteins from pathogens inside cell
22
Q
MHC class II displays
A
- fragments of proteins from pathogens living outside a cell
23
Q
signal 1 of T cell activation
A
- TCR binding a peptide
24
Q
signal 2 of T cell activation
A
- CD28 binding to B7
25
in absence of costimulatory signal
- T cells become anergized
| - no longer responsive to antigen stimulation
26
how costimulation works
- CD28 binds to B7
- protein kinases phosphorylate ITAMS on CD3 proteins
- signal transduction
27
cytokine that T cell proliferation is dependent on
IL-2
28
initiation and expression of IL-2 requires
- signals delivered by TCR:MHC coreceptor complex
| - and CD28
29
IL-2 functions in what kind of manner?
- autocrine
30
how IL-2 promotes cell division and clonal expanstion
- binds to CD25 receptor upregulated by activated T cells
31
effector functions of CD4+ T cells in cell-mediated immunity
- activate macrophages for killing of phagocytosed microbes
- CD40-40L
- interferon gamma
32
effector functions of CD4+ T cells in humoral immunity
- bind to B-lymphocyte
- CD40-40L
- secretion of antibodies with enhanced abilities to neutralize and eliminate antigens
33
host defense of TH1
- intracellular microbes
34
host defense of TH2
- helminthic parasites
35
host defense of TH17
- extracellular bacteria, fungi
36
initiating cytokine to produce TH1
- IL-12
| - IFN-gamma
37
initiating cytokine to produce TH2
- IL-4
38
initiating cytokine to produce TH17
- IL-6
- IL-23
- TGF-Beta
39
CD4 T cell proliferation cytokine
- IL-2
40
cytokines secreted by TH1
- IFN-gamma
- TNF-alpha
- proinflammatory
41
cytokines secreted by TH2
- IL-4
- IL-5
- IL-13
42
cytokines secreted by TH17
- IL-17A/F
| - IL-22
43
function of interferon-gama
- stimulates macrophages to ingest extracellular bacteria and viruses
- induces IgG2a and IgG3 class switching by B cells
- blocks differentiation of TH2 cells
44
IgG2a and IgG3 class switching by B cells function
promotes opsonization
45
source of IL-4
- basophils
46
function of IL-4
- promotes B cell proliferation
- enhances IgE class switching
- recruits eosinophils
- blocks differentiation of TH1 cells
47
function of IL-5
- elicits B cell growth
- activates eosinophils
- enhances IgE production
48
function of IL-17
- stimulation of inflammation
| - increased barrier function
49
how CD4+ T cells helps CD8+ T cells
- produce cytokines that stimulate CTL differentiation
| - enhance ability to APCs to stimulate CTL differentiation
50
CD8+ cytotoxic T cell effector mechanisms
- antigen recognition and binding of CTL to target cell
- CTL activation and granule exocytosis
- apoptosis of target cell
51
aberrantly high level of T cell activation associated with
- autoimmune disease
| - SLE
52
aberrantly low level of CD4 T cells problem in
- HIV/AIDS
53
success of organ transplant due to
- suppression of T cell activation
54
T cell activation by bacterial toxin can lead to
- massive T cell responses
| - TSS, food poisoning, etc
55
immunotherapy of cancer highly dependent on
- T cell activation
56
strategy of immunosuppression relied heavily on
- blocking T cell activation
