Non-specific factor enhancement of human in vitro antigen-dependent antibody synthesis: role of B cell activation and T cell help.
Lectin-free supernatants obtained from PWM-stimulated lymphocytes, enable B cells to proliferate and secrete immunoglobulin. Both functions are augmented by the addition of irradiated T cells. In the presence of antigen, these supernatants also enhance specific anti-tetanus toxoid antibody production. The components of the supernatant responsible for these activities have a molecular weight between 30,000 and 60,000, and have the characteristics of non-specific factors: they are genetically unrestricted, and do not bind to either antigen or anti-DR affinity columns. There is no evidence that the partial T dependency of these factors is an indication that their target is a T cell. Instead, T cells appear necessary to move the B cell into a state of activation in which it becomes responsive to the factor. Alternative activation signals such as Staph. A. Cowan can substitute for T cell help in the proliferative response, but not for immunoglobulin or antibody synthesis. The implications of these results for the approaches used to detect and classify B cell growth factors are discussed.
D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D002850:Chromatography, Gel; D006133:Growth Substances / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D015847:Interleukin-4; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D008222:Lymphokines / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology*
D006133:Growth Substances; D007074:Immunoglobulin G; D008222:Lymphokines; D015847:Interleukin-4