Question

2) Class I major histocompatibility complex proteins are needed for:

a) interacting with T cell receptors

b) stimulating T cell activation

c) interacting with CD8 proteins

d) binding and displaying portions of foreign proteins

e) all answers above

Answer 1

Option (e) All nucleated cells possess MHC I molecule on their surface. The exogenous antigens are taken up by the cell , which are processed proteasomally in the cytoplasm are moved to Endoplasmic Reticulum and are assembled with MHC molecule. These are then presented on the external surface of cell. The peptide MHC I complex interacts with CD8 protein on Tc cell and present antigen to them . This causes the activation of the cell Tc cell and causes their transformation to cytotoxic T cell .