H-2 Mutations: Their Genetics and Effect on Immune Functions

This chapter discusses the use of H-2 mutations to study functions of the murine major histocompatibility complex. A single H-2 locus can control a variety of immunologic phenomena, and strong MLC reactions can occur to H-2K and D antigens as well as to I region antigens. Histogenetically and serologically detectable antigens are of comparable complexity and small changes in the H-2 molecule—a single amino acid substitution—can have drastic effects on phenotype. The chapter describes methods of detection and analysis of histocompatibility mutations in general and H-2 mutations in particular. The knowledge of H-2 mutations is related to the perennial problem of polymorphism. The individual immune functions are discussed, and data are presented on the way mutations change these functions. In the allograft reaction—the reaction on which the detection of H-2 mutations is based—antigens carried by the transplant are recognized by specific receptors on T lymphocytes. In vitro studies indicate that the H-2 antigens recognized by T cells are complex in the sense that different T cells presumably recognize different portions of the H-2 molecule.