Peptide antigen presentation to T cells I: MHC antigen proteins and antigen processing

Question 1

MHC (Major histocompatibility complex)

Answer 1

This is the locus that encodes for a set of proteins essential for the adaptive immune system to recognize foreign molecules in vertebrates, which in turn determines histocompatibility. The MHC determines compatibility of donors for organ transplant.

Question 2

MHC molecules

Answer 2

Highly polymorphic cell surface proteins encoded by MHC class I and MHC class II genes involved in presenting peptide antigens to TCR of T cells

Question 3

MHCI

Answer 3

Polymorphic cell surface proteins encoded by MHC locus and expressed on all nucleated cells. They present antigenic peptides generated in the cytosol to CD8 T cells and also bind the co-receptor CD8

Question 4

MHCII

Answer 4

Polymorphic cell surface proteins encoded by MHC locus and expressed on specialised antigen presenting cells. They present antigenic peptides derived from internalised extracellular pathogens (phagocytosed or endocytosed) to CD4 T cells and also bind the co-receptor CD4

Question 5

TAP1 and 2

Answer 5

(Transporters associated with Antigen Processing) Translocate peptides from cytosol into ER lumen

Question 6

HLA (Human Leukocyte Antigen) Complex

Answer 6

This is the name for the human MHC complex which is a locus encoding the human counterparts of MHC I and II proteins and other proteins involved in antigen presentation

Question 7

HLA-A, -B, -C

Answer 7

These are the highly polymorphic human MHCI cell surface proteins found on all nucleated cells

Question 8

HLA-DP, -DQ, -DR

Answer 8

These are the highly polymorphic human MHCII cell surface proteins found on antigen presenting cells