Genetic Control of Cell‐mediated Immunity in the Rat. I. Transfer of DTH to Bacterial Antigens Is Restricted by the B Region of Rt1.

The genetic basis of allogeneic restriction in the transfer of delayed type hypersensitivity (DTH) to soluble Listeria monocytogenes antigens (LMA) in rats was analysed using a set of congenic strains. The DTH parameter assayed was the localization of radiolabelled donor lymphoblasts in subcutaneous antigen stimulation sites in the ear. Sharing of the RT1,B region between the donor and host was essential for the transfer of DTH to LMA, which suggests that the RT12.B region codes for restriction elements controlling antigen recognition by TDTH cells. The recombinant haplotype RT1 rl was exceptional in that transfer of DTH to A-region matched recipients was, at least in part, possible, Measurement of donor lymphoblast localization in DTH sites afforded an opportunity to quantify allogeneic effects influencing localization of sensitized donor cells in DTH sites borne by alien recipients. Both RT1.B and RT1.A region differences could induce allogeneic effects, but they were an order of magnitude lower than those based on restricted recognition by donor T cells.