I-J: An Inducible Isomorphic Receptor Involved in the H-2-Restricted Cell Interaction and Inhibition

Abstract

I-J still remains to be a premium grade paradox in H-2 genetics. Although it is not a direct product of H-2 genes, its polymorphism is clearly influenced by the intra H-2 genes. Recent functional data suggested that I-J is associated with the inducible T cells receptor for self class II antigens (1,2). It has been found that some of the anti-I-J monoclonal antibodies (mAb) could block the syngeneic and allogeneic mixed lymphocyte reactions (MLR) by reacting with the responder but not with stimulator cells (1). The I-J epitopes on responder cells were inducible in allogeneic bone marrow chimeras (2). Since some of the anti-I-J mAb were able to inhibit the H-2-restricted T helper cell (Th) function, we have recently tested their effect on Th and T cell clones derived from various intra H-2 recombinant mice and their bone marrow chimeras (3). The following are the summary of experimental results which suggest that I-J is an inducible isomorphic marker different from both class II products and conventional class II restricted T cell receptors.