title: Direct T helper-B cell interactions induce an early B cell activation antigen.
abstract: We have explored the consequences for the B cell of cognate interaction with T cells. Early expression of the B cell-restricted cell surface activation antigen, BLAST-2, has been used as an assay system to measure direct T-B cell collaboration. BLAST-2 is preferentially expressed by allogenic B cells cultured with MHC class II antigen-restricted Th clone cells matched to the DR specificity of the target B cells. B cells cultured with DR-mismatched allospecific Th cells express minimal BLAST-2. Th cell-induced BLAST-2 expression appears to be accessory cell independent and occurs as early as 8 h after initiation of culture, with peak expression at 18 h. Direct T-B cell contact, rather than Th-derived lymphokines, provides the most efficient stimulus for BLAST-2 expression. Crosslinking of sIg on B cells is a poor stimulus for BLAST-2 expression. The BLAST-2 assay permits the evaluation of early events associated with B cell activation through cognate interactions, and may facilitate subsequent studies of the mechanism of B cell differentiation.
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000276:immunology; D000938:Antigen-Presenting Cells / Q000502:physiology; D000944:Antigens, Differentiation, B-Lymphocyte; D000954:Antigens, Surface / Q000096:biosynthesis*; D001402:B-Lymphocytes / Q000276:immunology*; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D007700:Kinetics; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000502:physiology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D014301:Trinitrobenzenes / Q000276:immunology
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000944:Antigens, Differentiation, B-Lymphocyte; D000954:Antigens, Surface; D006684:HLA-DR Antigens; D008222:Lymphokines; D014301:Trinitrobenzenes