title: One out of five peripheral blood B lymphocytes is activated to high-rate Ig production by human alloreactive T cell clones.
abstract: Human alloreactive helper T cell clones were isolated from a secondary mixed lymphocyte reaction by limiting dilution in the presence of irradiated stimulator cells and T cell growth factor (interleukin 2). When cultured with B cells and macrophages possessing the relevant alloantigens, the T cell clones proliferated and induced a strong B cell activation with production of high immunoglobulin levels. Limiting dilution of the B cells from the peripheral blood showed that about one in 5-10 can be activated to produce IgG, one in 10 IgM, one in 20-40 IgA and one in 2000-5000 IgE. Following stimulation by the relevant alloantigen, the clones were able to help also B cells that lacked the alloantigen, indicating that a direct T-B cell interaction is not required. This method is particularly interesting because it is suitable for the clonal analysis of a B cell subset that is triggered in the absence of antigen by an unrestricted T cell help.
mesh_terms: D000921:Antibody-Producing Cells / Q000276:immunology; D000937:Antigen-Antibody Reactions; D001402:B-Lymphocytes / Q000276:immunology*; D002452:Cell Count; D002999:Clone Cells / Q000276:immunology; D006801:Humans; D007126:Immunoglobulin Allotypes / Q000096:biosynthesis*; D007519:Isoantigens / Q000276:immunology; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D013234:Stem Cells / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D007126:Immunoglobulin Allotypes; D007519:Isoantigens