The major histocompatibility complex of Rhesus monkeys. XII: Cellular typing for D locus antigens in families.

Typing cells (TC) were used for the identification of D locus antigens in rhesus monkey families. The antigens defined by this cellular method always segregated with the other RhLA-controlled markers except in one offspring with a proven recombination within the RhLA region; in that case, the D antigen was inherited in coupling with an antigen of the Ia1 locus (the analog of the human DR locus). With two exceptions, each TC or group of TC's was associated with one of the serologically defined Ia1 antigens. The two exceptions were associated with "blanks" of that series. Interestingly, two independent (mutually MLC responsive) TC groups appeared to be associated with the same Ia1 antigen 75. Equally noteworthy was the observed "inclusion phenomenon" among cells of several TC groups, each associated with a single Ia1 antigen or blank of that series. In these cases, some of the TC's of the group were unidirectionally MLC-responsive against other cells of the same group. Certain pitfalls of cellular typing are discussed; unexpected "false positive" results were attributed to prior immunization with products of non-D loci which have described recently (van Es & Balner 1978b).