Typing for MLC (LD). I. Lymphocytes from cousin-marriage offspring as typing cells.

WHEN it was observed that the majority of SD-identical unrelated individuals stimulated each other in the MLC test, it was postulated in agreement with earlier suggestions by others that MLC activation might be coded by a locus separate from the LA and Four loci." The existence of such a MLC locus is now generally accepted.^About 10% of the MLC tests between SD-identical unrelated persons are negative, indicating that a linkage disequilibrium exists between the MLC locus and the LA and Four loci. It is furthermore likely that SD-identical unrelated individuals who are also LD-identical carry MLC determinants that occur rather frequently.