Antigen processing and presentation of foreign antigens on MHC Class II Flashcards Preview

Basic Immunology- Module 1 > Antigen processing and presentation of foreign antigens on MHC Class II > Flashcards

Flashcards in Antigen processing and presentation of foreign antigens on MHC Class II Deck (19)
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1

What is MHC?

generic term to describe region of the genome found to control high or low immune responder status to specific antigens

2

What is the differene in strcture of class I and class II MH/C

class II is composed of an alpha and beta chain heterodimer whereas MHC I is composed a single heavy chain plus beta-2microglobulin

3

What cells can be induced to express class II MHC?

endothelial cells, mast cells, astrocytes

4

what cells constitutively express MHC-II?

dendritic cells, monocytes, macrophages, B cells

5

What controls induction of class II MHC?

transcription factors which bind to upstream promoter sequences

6

what is the function of HLA-DM?

catalyses peptide binding to MHC class II molecules

7

What is the function of MHC class II transactivator?

positive transcriptional co-activator of MHC-II genes

8

What is the function of polygeny?

presene of several different related genes with similar functions ensure that each individual produces a number of different MHC molecules

9

Which MHC protein is monomorphic?

DR alpha chain

10

Which type of class II molecule is expressed most?

HLA-DR

11

What are HLA-DM and HLA-DO?

intracellular class II moelcules with functions in peptide loading- remove the li derived CLIP peptide and load exogenous peptide

12

What happens to MHC class II molecules after biosynthesis?

stabilised with a peptide- CLIP dervied from a protein:invariant chain (li)

13

What is often found in the HLA-DR cluster?

an extra beta-chain gene whose product can pair with the DR alpha gene

14

What does the extra DR beta chain mean?

there are 4 types of MHC-II molecules from 3 sets of genes

15

Why are some HLA class II associated with autoimmunity?

polymorphic diferences in the peptide-binding groove impact the generation of disease through autoreactive CD4 cells

16

What can be used as a tool for counting and puridying peptide specific T cells?

streptavidin-bound HLA class II/peptide tetramers

17

What are products of individual MHC allels known as?

protein isoforms

18

what is a sequence motif?

the set of anchor residues (on binding peptides) that allow binding to a given isoform of an MHC molecule

19

What is an immune response gene defect?

when processing of a protein doesnt generate any peptides that can bind to MHC in an individual which results in individual being unresponsive to that antigen