HLA

Question 1

HLA

Answer 1

human leukocyte antigens - human MHC which functions as antigen presenting structures to T cells.

Question 2

Class I HLA

Answer 2

membrane bound glycoproteins expressed on all nucleated cells which present cytosolic antigens to CD8+ cytotoxic T cells - encoded by HLA-A, HLA-B, HLA-C - formed by alpha chain (HLA encoded) and beta micro globulin (nonHLA) - peptide groove is closed so can only hold 8-10 aa

Question 3

Class II HLA

Answer 3

membrane bound glycoprotein expressed primarily on antigen-presenting cells which present extracellular proteins to T cells. - encoded by HLA-DQ, HLA-DP, HLA-DR - formed by alpha and beta chain - peptide groove is holds 13-18aa

Question 4

Describe how peptide chains bind to HLA.

Answer 4

side chains of aa on the antigen peptides fit into ‘pockets’ on the floor of the peptide binding clefts while the rest of the peptide residues bow upwards to interact with TCR

Question 5

HLA Restriction

Answer 5

Describes how T cells are only able to recognize antigens when associated with the organisms’s own HLA haplotype and correct class.

CD8+ = HLA class I

CD4+ = HLA class II

Question 6

Describe the Class I HLA Pathway.

Answer 6

Question 7

Describe the Class II HLA pathway.

Answer 7

Question 8

cross-presentation

Answer 8

presentation of peptide antigen in HLA class I and class II to both types of T cell. done by professional APC cells.