Antigen Processing and Presentation at a Molecular Level

Abstract

The recognition of antigen by helper T-cells through their antigen specific receptor has been the center of intense investigation by many different researchers. Helper T-cells recognize antigen in association with a class II molecule on the surface of an antigen presenting cell. Unlike B-cells which generally recognize determinants found in the native form of the antigen, most T-cells recognize a non-native form of the antigen. It is this conversion of antigen from a native form to the form recognized by T-cells which has been operationally defined as antigen processing. Over the past four years, we have developed a system which utilizes the antigen hen egg-white lysozyme to determine at a molecular level 1) what antigen processing is, 2) how the determinant recognized by the T-cell is formed, and 3) what precisely is the ligand of the T-cell receptor. In this manuscript, we would like to initially review the concept of antigen processing at a molecular level and then present our results on the formation and recognition by the T-cell receptor of an antigenic determinant of HEL.