MHC I vs MHC II – What is the Difference?
(MHC I vs MHC II) Major Histocompatibility Complexes plays crucial role in activating Cell Mediated Immunity in our body. Tc cells and Th cells cannot recognise the peptide alone, they have to be presented peptides on MHC molecules.
MHC molecules present in humans are called HLA – Human Leucocyte Antigen. MHC molecules binds to peptide fragments derived from antigen degradation and display them on the cell surface for recognition by the appropriate T cells. It is also responsible for graft rejection.
MHC class I is present in all nucleated cells. RBCs does not have a nucleus and therefore does not contain MHC class I. It presents the peptide to Tc cells and thus they are involved in clearance of endogenous Ag.
MHC class II is present in Antigen Presenting Cells (APC) such as B cells, dendritic cells, macrophages. It presents the peptide to Th cells and thus they are involved in clearance of exogenous Ag.
Antigen Processing and Presentation | Part I | The Cytosolic Pathway
Antigen Processing and Presentation | Part II | The Endocytic Pathway
Reference book to follow for this topic: Kuby Immunology