Thrush - The MHC

Question 1

Which of the follow is most closely associated with inducing opsonization

Answer 1

C3b

Question 2

What is MHC important for

Answer 2

impt in self vs non self recognition; T cell recognition of Ag includes recognition of self MHC; reason why rejection of a transplant occurs; AKA human leukocyte antigens (HLA) - genes on ch. #6

Question 3

There are \_\_\_\_ diff groups of genes on the MHC locus. Class \_\_\_\_ MHC is expressed on most mucleated cells and present Ag to CD8 T cells. Can recognize any cells except \_\_\_\_. There are 3 diff class genes: \_\_\_\_ \_\_\_ \_\_\_ in humans that are codominantly expressed.
Class \_\_\_\_ MHC is exp primarily by professional APCs & present Ag to CD4 T cells. The genes they expresss include \_\_\_\_ \_\_\_\_ and \_\_\_ in humans. Class \_\_\_\_ MHC is secreted proteins found in serum and include complement proteins, some cytokines and proteins inv in Ag processsing

Answer 3

3; I; RBC; HLA-A, HLA-B, HLA-C;

HLA-DP; HLA-DQ; HLA-DR; II;

Question 4

MHC class 1 protein is a single chain associated with another protein not encoded for by the MHC locus: _____

Answer 4

beta 2- microglobulin

Question 5

MHC class II proteins are heterodimers coded for by the ___ and ___ genes within the MHC locus

Answer 5

alpha; beta

Question 6

MHC proteins are highly ____. Both alleles are expressed at once meaning their _____. Sincel closely linked, they have a low _____ frequency. MHC genes are _____. They have multiple similar genes. On human cells, get ___ diff class ____ MHC and ____ diff class ____ MHC proteins expressed.

Answer 6

polymorphic; codominant; recombination; polygenic; 6; I; 12; II

Question 7

The classical molcules inc; HLA-A, B, and C. Also HLA-DP, DQ and Dr. The non classical include HLA E, F, and G and include _____ cells and others. Don’t play a direct role in activating T cells. An ____ is a genetic sequence of a gene within a species

Answer 7

NK; allotype

Question 8

Humans inherit ____ of parents MHC genes but often can’t give parents organ/ tissues to a child.

Answer 8

1/2

Question 9

MHC class II looks kind of the same as class I. The impt distinction is that class II is made up of two different peptides, alpha and ____. Alpha I and and beta is the Ag ____ cleft

Answer 9

beta; binding

Question 10

Class I is called a ____ structure, so peptides are smaller. Class II is called an ____ ended structure, bc peptides can hang off of ends of molecule

Answer 10

closed; open

Question 11

A given MHC can bind a variety of different ____ peptides = promiscuous. Class I anchor residues at ends, often at position #___ and # _____.

Answer 11

antigenic; 2; 9

Question 12

Class I peptides came from ______ _____ peptides. There are ____ MHC class I molecules on surface of cell. Usually need ____ of a peptide to get Tc cell recognition. ____ are the preferred length of peptide and binds strongest

Answer 12

endogenous intracellular;

10^5; 100; Nonamers

Question 13

Class II peptides are _____ peptides and are degraded by the ____ pathway

Answer 13

exogengous; endocytic

Question 14

What are the Class II MHC cell types?

Answer 14

macrophages, dendritic cells and B cells

Question 15

Trancription factors and _____can regulate, increase, or decrease MHC expression. ____ and cancer cells can decrease or alter MHC expression of Class _____

Answer 15

cytokines;

Viruses; I

Question 16

When a peptide is presented to a Class I we call that a _____ cell. when a peptide is associated with class II we call that an _____ presenting cell

Answer 16

target; antigen

Question 17

____Ag’s (class I) go through the cytosolic pathway. All proteins are recycled. Proteins targeted for degradation have ____ attached to them. _____is a large enzyme complex that degrades proteins. ____ and ____ are enzymes that associate with the proteasome to cut proteins near ____ residues

Answer 17

Endogenous; ubiquitin; Proteasome; LMP2; LMP7; hydrophobic

Question 18

How do peptides associate with MHC class I

Answer 18

Endogenous pathway: Engogenous Ag is degraded by proteosome. peptides must get to rER. TAP binds peptides and allows the peptide to assicate with Class I and then class I peptide complex travels to the Golgi and then cell surface.

Question 19

How do peptides associate with MHC class II

Answer 19

Through the exogenous pathway. Macrophages, DCs and B cells bring in Ag in endocytic vesicle. AFter fusion of endosome with lysosome, the protein gets degraded

Question 20

How do you associate Ag peptide with class II and not with class I MHC?

Answer 20

The invariant chain associates with newly made class II. The invariant chain gets partially degraded to yield CLIP, which occupies class II bindng groove. Invariant chain and CLIP are degraded in endocytic compartment allowing exogenous Ags to assiciate with class II. HLA-DM binds to Class II and releases CLIP when Ag peptide is binding.