Cell Biology of Antigen Processing and Presentation to Major Histocompatibility Complex Class I Molecule-Restricted T Lymphocytes

Abstract

Publisher Summary This chapter presents an overview of T cell recognition and function. Complex organisms coevolved with a wide variety of microorganisms—viruses, bacteria, and simple eukaryotes—that reside within the cells or extracellular fluids of the host. In some cases, hosts and parasites mutually benefit from the relationship. In other cases, parasites are purely destructive. With few exceptions, T cells expressing CD4 recognize antigens in conjunction with class II molecules encoded by the major histocompatibility complex (MHC), whereas those expressing CD8 recognize antigen in conjunction with MHC class I molecules. This targeting is achieved by the direct interaction of CD4 and CD8 molecules with class II and I MHC molecules, respectively, bearing the antigenic determinants recognized by the T cell antigen receptor. The chapter outlines the history of the discovery of MHC restriction. The discovery of the MHC class I-restricted nature of TCD8+ recognition of virus-infected cells caused great excitement because it represented the first function to be ascribed to MHC class I gene products since transplantation rejection. Of the many clever models proposed to account for the phenomenon of MHC restriction, most proposed that the viral antigens recognized by TCD8+ were membrane glycoproteins. All of the viruses used in the initial studies were membrane viruses that expressed such proteins as part of their infectious cycles.