A novel human class II specificity, DQ "Wa," resides on DQ molecules of DR4,Dw15 and DRw8,Dw8 B-cell lines identified as DQ "blank".

The molecular localization of a novel human class II specificity, DQ "Wa," was investigated. A monoclonal antibody, HU46, which has previously been shown to react with DR4, Dw15 and DRw8, Dw8 B cells that type as DQ "blank," was used for the isolation and structural characterization of class II molecules bearing the DQ "Wa" determinant. The partial N-terminal sequence analysis of class II molecules bearing the DQ "Wa" determinant, purified from two B-cell lines, EBV-Wa (DR4, Dw15, DQ "blank") and GI (DRw8, Dw8, DQ "blank"), shows that the alpha and beta chain sequences are homologous to HLA-DQ. Within the limits of our analysis, the alpha and beta chains from both cell lines are identical. Both beta chains possess a phenylalanine residue at position 9 that differs from the tyrosine residue present at this position in beta chains of DQ alleles. These studies indicate that a novel human class II specificity, DQ "Wa," resides on a new allelic form of DQ molecules found in DR4, Dw15 and DRw8, Dw8 cells that are DQ "blank."