title: Soluble factors involved in B cell differentiation: identification of two distinct T cell-replacing factors (TRF).
abstract: Highly purified B lymphocytes cultured with affinity-purified goat anti-mouse IgM antibodies and B cell growth factor (BCGF) proliferate but fail to differentiate into immunoglobulin-synthesizing cells during 4-day cultures. Induction of immunoglobulin (Ig) synthesis depends on the presence of two additional T cell-derived factors (T cell-replacing factors [TRF]). One TRF, designated B15 1K 12-TRF, is found in the supernatant of B15 1K 12 T hybridoma cells. It is required relatively early in these cultures and appears to cause an increase in cell yield as well as Ig synthesis. The second factor, designated EL-TRF, is found in PMA-induced EL-4 supernatant. It appears to be different from both BCGF and IL 2 in that it can be separated from the former by isoelectric focusing and from the latter by phenyl-Sepharose chromatography. EL-TRF is still active if added on the last day of a 4-day culture. A model for the action of anti-IgM and these three T cell-derived factors in B cell activation and differentiation is proposed.
mesh_terms: D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000502:physiology; D000921:Antibody-Producing Cells / Q000166:cytology / Q000276:immunology; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D002454:Cell Differentiation; D005260:Female; D006133:Growth Substances / Q000502:physiology; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D007376:Interleukin-2 / Q000302:isolation & purification / Q000502:physiology; D015847:Interleukin-4; D015848:Interleukin-5; D007525:Isoelectric Focusing; D007700:Kinetics; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000302:isolation & purification / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D051381:Rats
chemical_list: D000888:Antibodies, Anti-Idiotypic; D006133:Growth Substances; D007075:Immunoglobulin M; D007376:Interleukin-2; D015848:Interleukin-5; D008222:Lymphokines; D015847:Interleukin-4