[Genetic control of mixed lymphocyte culture]

Eighteen healthy families were HLA typed with highly specific cytotoxic antisera; 10 of them were also HLA-DR typed. All of them were tested in the mixed lymphocyte culture. Two different methods of mixed lymphocyte culture-with respect to the number of cells used-were compared. The influence of D and DR antigens on mixed lymphocyte culture is discussed. A rather rare finding was that two unrelated people were homozygous for DR, but not for D and, hence, different with respect to their D and DR antigens. Seven individuals, among them two pairs of identical siblings, were found to be homozygous for HLA-D and HLA-DR. The possibility of using them as typing cells for the alleles of the HLA-D locus was discussed.