Question

1. Compare/contrast MHC-I and MHC-II proteins, including the types of cells that display each.

Answer 1

MHC molecules found on the surface of all nucleated cells of the body and are coded by MHC genes. MHC molecules are glycoproteins that are involved in adaptive immunity. There are two classes MHC I and MHC II.

Differences between class I and class II MHC

Encoding genes- In humans, MHC class I proteins are encoded by the HLA-A, HLA-B, and HLA-C genes. MHC Class II proteins are encoded by HLA-D genes

Location (Type of cell in which it is found)- MHC I molecules are found on all nucleated cells, MHC II molecules are only found on macrophages, dendritic cells, and B cells (antigen presenting cells (APCs) only).

Function- MHC I molecules present endogenous/intracellular antigens to the effector T cells involved in cellular immunity. MHC II molecules present exogenous antigens taken by (APCs) for the initial activation of T cells.

Differences in T cell receptor (Type of receptor)- MHC I molecule present antigens to CD8+ receptor of T cells. MHC II molecule present antigens to CD4+ receptor of T cells.

Structure-MHC I molecules consist of one α chain (membrane spanning) produced by MHC genes, and one β chain produced by the β2-microglobulin gene. MHC II molecules consist of two α and β chains (membrane spanning) both produced by MHC genes.