title: Isolation and characterization of B cell differentiation factor (BCDF) secreted from a human B lymphoblastoid cell line.
abstract: A subclone of a human B lymphoblastoid cell line, CESS-2, spontaneously secreted a kind of BCDF (B-BCDF) in their culture supernatant without any stimulation. B-BCDF induced IgG and IgM secretions in human B lymphoblastoid cell lines, CESS cells and CL-4 cells, respectively. BCDF-responsive CESS cells expressed IgG on their surface, whereas CESS-2, which were able to secrete B-BCDF, did not express surface IgG. B-BCDF could induce Ig-secretion in SAC-stimulated low density peripheral B cells, but did not induce Ig secretion in nonstimulated B cells. B-BCDF did not show any IL 2, BCGF, or gamma-interferon activities. B-BCDF was highly purified by gel filtration on an AcA-34 column, by chromatofocusing and ion exchange chromatography on an HPLC system, and by gel filtration on an HPLC column. Highly purified preparations showed a single protein band in SDS-PAGE analysis. The m.w. and isoelectric points of the factor were 20,000 and pH 5.1 to 5.2, respectively. The minimum protein amount required for Ig induction in B cell lines was 16 ng/ml.
mesh_terms: D000921:Antibody-Producing Cells / Q000378:metabolism; D001402:B-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D006133:Growth Substances / Q000096:biosynthesis / Q000302:isolation & purification* / Q000502:physiology; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis; D007372:Interferons / Q000502:physiology; D007376:Interleukin-2 / Q000502:physiology; D015847:Interleukin-4; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000096:biosynthesis / Q000302:isolation & purification* / Q000502:physiology; D008970:Molecular Weight; D013205:Staphylococcal Protein A / Q000494:pharmacology
chemical_list: D006133:Growth Substances; D007136:Immunoglobulins; D007376:Interleukin-2; D008222:Lymphokines; D013205:Staphylococcal Protein A; D015847:Interleukin-4; D007372:Interferons