RhLA complex of Rhesus monkeys. X. Implications of the association between D and Ia1 locus antigens.

A high association has been found between D-locus determinants defined by cellular methods (typing cells) and the serologically defined B cell or Ia antigens controlled by the Ia1 locus. Data from recombinant offspring in two rhesus families place the Ia1 locus within RhLA, in the close vicinity of the D or major MLC locus. In fact, identity between the products of those two loci cannot be excluded. Further, it was shown that cells proven to be homozygous for Ia1 antigens, are nearly always typing cells (and therefore homozygous for D-locus determinants) and, conversely, that proven typing cells carry only a single Ia1 antigen and are thus probably homozygous for Ia1 products. In addition, it could be demonstrated that matching for Ia1 antigens greatly facilitates the detection of unrelated individuvals who are mutually non-reactive in MLC. This "predictive value" of Ia1 matching has important implications for the selection of optimal donors for organ transplantation.