Alloantiserum recognizing a DQw2 split which is associated with DR3

A typing serum MUE 38539 II, was found to recognize a DR3-associated split of DQw2. In cytotoxicity tests, MUE 38539 II yielded positive test results with B lymphocytes but not with monocytes of DR3-positive cell donors. This was in contrast to other typing reagents for DR3 that react with B lymphocytes as well as monocytes. Lymphocytotoxicity tests using MUE 38539 II were negative with DR7- and DQw2-positive cells. The assumption that the serum recognizes a DR3-associated split of DQw2, and not DR3 itself, was confirmed by the lack of reactivity with a DQw4- and DR3-positive lymphoblastoid cell line (RSH). The assumption was also corroborated using reagents from a family in which DR3 and DQw2 were not found in the usually described linkage. In two lines, DR3 was associated with DQw- (2707 and 2710), and in the cell line 2704, DQw2 was associated with DRw-. The serum MUE 38539 II was exclusively cytotoxic with lymphoblastoid cell lines from those family members who were positive for DQw2, independently of the DR3 antigens of the cells.