IgE production after antigen-specific and cognate activation of HLA-DPw4-restricted T-cell clones, by 78% of randomly selected B-cell donors

The frequency of expression of the MHC class II antigen, HLA-DPw4, in the c aucasoid population is approximately 78%, and is unmatched by phenotypic fr equencies of other HLA class II molecules. Here we describe three human Der -P1-specific T-cell clones (TCC), restricted by the HLA-DPw4-variant HLA-DP B1*0401, of which two TCC also responded to antigen, presented on HLA-DPB1* 0402. Thus, randomly selected caucasoid donors present a 78% chance for a c orrect march with these HLA-DPw4-restricted TCC. This allows comparative in vitro antigen presentation studies with various antigen presenting cells ( APC) from different (healthy or diseased) donors without the variable influ ence of responding T cells. It was subsequently demonstrated that the TCC c an be used to study antigen-induced IgE production in randomly selected pri mary B cells. Cognate HLA-DPw4-restricted antigen presentation caused enhan ced immunoglobulin production of IgE, IgG1, IgA and IgM, of which only IgE induction was reversed by addition of anti-IL-4 antibodies. Human Immunolog y 61, 789-798 (2000). (C) American Society for Histocompatibility and Immun ogenetics, 2000. Published by Elsevier Science Inc.