CD4 and CD8 may adopt a similar mode of binding to their MHC ligands

Abstract

A theoretical scheme is proposed by which the type-specific cell surface receptors of T-lymphocytes, CD8 and CD4, bind class I and II MHC proteins in a similar manner. The scheme has equivalent residues in the C'/C'' loop-C'' strand-C''/D loop region in domain 1 of CD4 and CD8 alpha binding to equivalent residues in the C and D beta-strands and C/D loops in HLA-DR beta 2 (class II) and HLA-A2 alpha 3 (class I) respectively through a series of electrostatic, hydrogen and hydrophobic bonds.