Female popliteal lymph node responses to H-Y antigen on male thymocytes in mice. I. Regulation of primary and secondary responses by H-2-associated Ir genes.

H-2-linked genes which control popliteal lymph node (PLN) immune responses to the H-Y antigen were analysed. It was found that at least two genes or two groups of genes are involved in the genetic control and are responsible for the four variants of relations observed between the primary and the secondary response: +/-, +/+, -/+ and -/- ('+' and '-' stand for a high and a low response, respectively). The results obtained with H-2 recombinant haplotypes indicated that the genes controlling the primary and secondary responses map to the left and to the right of the E alpha locus, respectively. A high primary response was observed in the presence of b alleles at K, A beta, A alpha, and E beta loci, whereas a high secondary response occurred only in the presence of d alleles in the chromosomal segment between E alpha and D loci. From the experiments with F1 hybrids it is clear that low secondary responses are, for the most part, dominant and that the two seemingly separate control mechanisms for the primary and secondary responses may interact.