At least two loci of the major histocompatibility complex can determine mixed lymphocyte stimulation in the rat

Analysis of a recombinant haplotype of the major histocompatibility complex showed that two genetically separable loci (or groups of loci), LD--1 and LD--2, determine mixed lymphocyte stimulation in the rat. LD--1 maps into the H--1B region which contains the Ir genes and is associated with strong, mixed lymphocyte stimulation. LD--2 maps into the H--1A region and determines weak stimulation. LD--1 and LD--2 determinants can be detected by primed lymphocyte typing.