title: Differentiation factors for human specific B cell response.
abstract: Nonspecific T cell factors produced by lectin-activated human peripheral blood lymphocytes (PBL) were used to restore the T-dependent B cell response to trinitrophenyl-polyacrylamide (TNP-PAA). Preincubation experiments with the particulate antigen TNP-PAA and/or a soluble TNP-protein conjugate show that a first specific signal provided by the antigen and nonspecific lymphokines sequentially acts on B cells. By gel filtration the T cell-replacing factor (TRF) activity is present in the 30-15-kDa fraction of T cell supernatants and is associated to interleukin 2 (IL2). However, absorption of IL2 does not abolish the TRF activity. Moreover, chromatofocusing of this 30-15-kDa material allows the obtaining of an IL2-free fraction containing a differentiation factor (with an isoelectric point of 5.7 +/- 0.2). The ability of this fraction to restore the anti-TNP response is manifest in the presence of a 50-kDa B cell growth factor. This latter, prepared by a combination of absorption on concanavalin A-Sepharose and gel filtration, was IL2 free and unable to support the anti-TNP response. We thus directly demonstrate that in the absence of IL2 three separate signals (the antigen, T cell-derived growth and differentiation factors) are involved in human-specific B cell response.
mesh_terms: D001402:B-Lymphocytes / Q000166:cytology* / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D002478:Cells, Cultured; D006133:Growth Substances / Q000378:metabolism / Q000494:pharmacology*; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism / Q000494:pharmacology; D015847:Interleukin-4; D008213:Lymphocyte Activation / Q000187:drug effects; D008211:Lymphocyte Cooperation; D008222:Lymphokines / Q000378:metabolism / Q000494:pharmacology*; D008863:Microspheres; D010835:Phytohemagglutinins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000378:metabolism*; D014301:Trinitrobenzenes / Q000276:immunology
chemical_list: D006133:Growth Substances; D007376:Interleukin-2; D008222:Lymphokines; D010835:Phytohemagglutinins; D014301:Trinitrobenzenes; D015847:Interleukin-4