Relation Between HLA‐DW and the B‐Lymphocyte Specificities

Homozygous DW typing cells were tested for six B-lymphocyte specificities. All four of the second locus specificities of B lymphocytes were strongly associated with the DW specificities. DW1 typing cells were B group 6, DW2 were B4, DW3 were B5, and LD107 were B3. The first B-cell locus antigens 1 and 2 tended to be uniform within the DW groups. From an analysis of the typing responses of a panel of cells to the homozygous typing cells, it has become apparent that the first B-locus specificity present on the homozygous typing cells also plays a role in determining whether a typing response is obtained or not. Thus, the DW3 typing cells were themselves B2 and B5, and cells having B2-B5 were most frequently nonreactive to DW3 in mixed lymphocyte culture. Homozygous typing cells therefore mainly detect the second B-cell locus antigens and, to a lesser degree, the first locus specificities. Stated another way, homozygous typing cells do not define a single specificity, but rather the presence of two B-lymphocyte specificities, even though their responses often reflect matching of only the second B-locus specificity.