Human Ia-like antigens associated with HLA-d.

Antisera raised with HLA-A- and -B-compatible, HLA-D-disparate combinations were cytotoxic to B lymphocytes from the immunizing donor's HLA-D phenotype. Four antisera recognized structures closely associated with the HLA-D determinants Dw2, Dw3, Dw4, and LD 108. One antiserum had a broad reactivity pattern, including Dw3, Dw6, and some unknown specificity(ies). In population and family studies these B-lymphocyte antigens behaved as if they were governed by one genetic locus in the B-D region of the HLA complex. Furthermore, the antisera were cytotoxic to a minor concavalin-A-reactive T-cell subpopulation. The antisera had previously been shown to inhibit the stimulating cells in mixed lymphocyte culture and to be capable of inhibiting the Fc receptor in the EA rosette assay. We conclude that the antisera produced by this method recognize Ia-like antigens closely associated with the HLA-D determinants.