Genetic control of the cellular in vitro response to the H-Y antigen in the rat.

The immune response against the male-specific H-Y antigen has been studied in RT1 congenic rat strains by assaying the cytotoxic and proliferative response in vitro after in vivo priming. The capacity to respond is associated with the RT1a and RT1n major histocompatibility haplotypes, and nonresponsiveness with the RT1u haplotype. Both, genes of the RT1.A region, which encodes class I antigens, and of the RT1.B/D region, which includes class II and transporter genes, are involved in the genetic control. In F1 hybrids haplotype preference of H-Y restriction occurs in favor of RT1a. Cross-priming can be induced in F1 hybrids by parental cells for RT1a-restricted cytotoxic and proliferative T cells. Allopriming is successful only in the RT1a-carrying strain, whereas xenopriming with mouse cells could not be elicited. The results are discussed in the context of current views on processing and presentation of antigens, and their relevance for transplantation is pointed out.