Immunochemical Definition of the New Dr Specificity 8WDRw13

Using two alloantisera produced by planned immunization of blood donor volunteers, a new specificity was defined residing on human Ia molecules. The specificity is possessed by the following human lymphoid cell lines: Reh, NALM-1, B89, KM-3 and BJAB, and appears to be the same as the DRw13 specificity discovered in the 8th International Histocompatibility Workshop. A radioimmunoassay for typing w13 on peripheral blood lymphocytes was established. A population and family study supports the genetic control by the HLA-DR locus. The phenotypic frequency in an Italian population was 3.7 percent. The relationship between w13 and the MT2 supertypic specificity was confirmed at the molecular level and the papain sensitivity of w13-carrying molecules was determined.