Influence of the Major Histocompatibility Complex on T-Cell Activation

Abstract

This chapter provides a better understanding of the function of histocompatibility gene products and of the advantages of polymorphism of the loci that code for these products. The chapter considers some of these investigations and offers certain models that elucidate the role of the histocompatibility gene products in T-cell activation. The effects these genes may have in determining resistance to certain tumors are discussed in the chapter. Genes of the major histocompatibility complex (MHC) exert a profound influence on T lymphocytes. The MHC-linked Ir genes control T-cell activities and T-cell-dependent functions, and the reactivities of various T-cell subsets are restricted by distinct MHC genes. I-region gene products govern the immune responses of T H and T D cells to antigens presented by macrophages and B cells. H-2K and H-2D gene products influence the response of Tc cells, which play an essential role in resistance to virus infections. The exact manner by which the MHC produces such effects is not known, but several possible mechanisms are discussed in this chapter.