The major histocompatibility complex of rhesus monkeys. VI. Serology and genetics of Ia-like antigens.

The serology and genetics of11 new cell surface alloantigens of rhesus monkeys are described: They are controlled by the mamor histocompatibility complex but are distinct from the conventional serologically defined (SD) antigens ofRhL-A. The new specifications are termed "Ia-like" because ofserological, immunocytological and other characteristics reminiscent of Ia-antigens of the mouse. Population and family analyses led to the postulation of two segregant series controlling eight of the 11 Ia-like specificities of the monkey. Strong linkage disequilibria with SD2 antigens and genetic mapping on the basis of segregation studies in recombinant offspring in the monkey families, places at least one of the two loci in the vicinity of the SD2 locus of RhL-A, not in the region of the major MLC or LD1 locus. For this and other reasons, the new B-cell alloantigens of rhesus monkeys are not believed to be similar to or associated with the stimulator antigens of LD1. The biological function(s) of the Ia-like antigens of primates are as yet unknown.