MHC Flashcards
1
Q
What do antigen receptors of B cells recognize?
A
- macromolecules
- proteins
- polysaccharides
- lipids
- nucleic acids
- small chemicals in soluble form
2
Q
what do antigen receptors of T cells recognize
A
- peptide fragments of protein antigens
- only when present on MHC cells
3
Q
T-cell mediated immune responses only against
A
- protein antigens
- produced in host cells
- taken up by host cell
4
Q
antigens can only be recognized in the proper context
A
- location (anatomic)
- setting (micranatomic/molecular)
5
Q
where does antigen presentation occur
A
- lymph node collects antigen from epithelium and connective tissues
- blood-borne antigens are captured by antigen-presenting cells in the spleen
6
Q
langerhans cells
A
- dendritic cells in the skin
- as they capture antigen, they get signals to travel to T cell areas within lymph nodes
7
Q
where are proteins displayed or recognition by T lymphocytes
A
- peripheral lymphoid organs
- lymph nodes
- spleen
8
Q
major location of conventional dendritic cells
A
- tissues
9
Q
major location of plasmacytoid dendritic cells
A
- blood
- tissues
10
Q
major cytokines produced by conventional dendritic cells
A
- pro-inflammatory
- TNF
- IL-6
- IL-12
11
Q
major cytokines produced by plasmacytoid dendritic cels
A
- type I interferons
12
Q
major functions of conventional dendritic cells
A
- induction of T cell responses against most antigens
13
Q
major functions of plasmacytoid dendritic cells
A
- antiviral innate immunity
- induction of T cell responses against viruses
14
Q
after dendritic cells capture microbial antigens
A
- activated
- and leave their location
- migrate to draining lymph nodes
15
Q
what attracts dendritic cells to the lymph nodes
A
- chemokines produced in the lymphatics and nodes
16
Q
how to the dendritic cells mature and acquire the ability to present antigen
A
- in response to signals induced by the microbe such as Toll like receptor signals and cytokines
17
Q
immature dendritic cells express
A
- surface receptors that capture microbial antigen
18
Q
mature dendritic cells express
A
- high levels of MHC molecules and costimulators
- to stimulate T cells
19
Q
dendritic cell class II MHC - constitutive or inducible
A
- constitutive
20
Q
dendritic cell class II MHC increases with
A
- maturation
21
Q
dendritic cell class II MHC increases by (cytokine)
A
- interferon gamma
22
Q
dendritic cells costimulators - constitutive or inducible
A
- constitutive
23
Q
dendritic cells costimulators increases with
A
- maturation
24
Q
dendritic cells costimulators inducible by
A
- TLR ligands
- interferon gamma
- CD40-CD40L interactions
25
dendritic cells principle function
- initiation of T cell responses to protein antigens
26
macrophages class II MHC - constitute or inducible
- inducible by interferon gamma
INTERFERON GAMMA MAKES MACROPHAGES HUGE AF
27
macrophages costimulators - constitutive or inducible
- inducible by:
- TLR ligands
- interferon gamma
- CD40-CD40L interactions
28
macrophages principal function
- effector phase of cell-mediated immune responses
29
B lymphocytes class II MHC - constitutive or inducible
- constitutive
30
B lymphocytes class II MHC increased by
- IL-4
31
B lymphocytes costimulators induced by
- CD40-CD40L interactions
| - antigen receptor cross linking
32
B lymphocytes function
- antigen presentation to CD4+ helper T cells in humoral immune responses
33
MHC I pathway (intrinsic or extrinsic)
- intrinsic
34
MHC II pathway (intrinsic or extrinsic)
- extrinsic
35
3 processing pathway
- intracellular
- intrinsic
- extrinsic
36
3 presentation pathways
- extracellular/surface
- multi-molecular
- multi-cellular
37
MHC gene products in humans are called
- human leukocyte antigens
| - HLAs
38
most important HLAs
- Class I and Class II
39
HLA gene and haplotypes
- certain haplotypes can determine if you are protected or predisposed to certain autoimmune diseases
40
MHC gene expression
- codominantly expressed
41
MHC genes and diversity
- highly polymorphic
42
co-dominant expression
- both parental alleles of each MCH gene are expressed
43
significance of codominant expression for MHC
- increases the number of different MHC molecules that can present peptides to T cells
44
significant of polymorphous genes for MHC
- ensures that different individuals are able to present and respond to different microbial peptides
45
Class II MHC found on
- dendritic cells
- macrophages
- B cells
46
Class I MHC found on
- all nucleated cells
47
MHC Class I chains
- alpha chain
| - beta-2 microglobulin (not coded in MHC)
48
MHC Class I binding cleft
- alpha 1 and alpha 2 domains
49
size of peptide MHC Class I can bind
- 8-11 AA in size
50
part of Class I MHC that binds CD8
- alpha 3
51
polymorphisms in MHC Class I
- mostly alpha 1 and 2
52
MHC II chains
- alpha and beta chains
53
size of peptide MHC II can bind
- 10-30 AA
54
part of MHC II that binds CD4
- beta 2
55
number of antigens MHC can present at a time
- only one peptide at a time
| - peptides only
56
how many MHC molecules on the surface
- 10^5
57
how what percentage of MHC must be bound to be activated
- less than 1%
58
significance of slow off rate of MHC molecule
- displays bound peptide for long enough to be located by a T cell
59
CD4 T cell responses
- classic T helper
- cell mediated immunity
- humoral responses
- T regulatory cells
60
CD8 cell responses
- classically CTL responses
- kills infected cells
- antiviral immunity
61
MHC II enzymes responsible for peptide generation
- endosomal and lysosomal proteases
62
MHC I enzymes responsible for peptide generation
- cytoplasmic proteasome
63
site of peptide loading MHC II
- specialized vesicles
64
site of peptide loading MHC I
- endoplasmic reticulum
65
molecules in volved in transport of peptides and loading of MHC molecules on MHC II
- invariant chain
| - DM
66
molecules in volved in transport of peptides and loading of MHC molecules on MHC I
- TAP
67
MHC II Pathway
- uptake of EXTRACELLULAR proteins into vesicular compartments of APC
- processing of internalized proteins in endosomal/lysosomal vesicles
- biosynthesis and transport of class II MHC molecules to endosomes
- association of processes peptides with class II MHC molecules in vesicles
- DM provides the switch
- expression of peptide MHC complexes on cell surface
68
MHC Class I pathway
- production of proteins in cytosol or phagosome bringing in
- proteolytic degradation of proteins by proteasome
- transport of peptides into ER by TAP for assembly
- packaged in Golgi
- released in exocytic vesicle for surface expression
69
dendritic cells can also present to
- CD8 T cells
| - through MHC1 expression
70
how dendritic cells present to CD8 T cells
- infected cells and viral antigens picked up by APC
| - cross-presentation of viral antigen
71
roles of APC
- co-stimulators
- secrete cytokines
- present a context for immune regulation
- may limit immune responses
72
important chromosome for human HLA
- chromosome 6
