title: A T-helper cell x Molt4 human hybridoma constitutively producing B-cell stimulatory and inhibitory factors.
abstract: A human T-T hybridoma clone with helper cell phenotype was established from fusions between a HPRT- variant of the human T-cell lymphoma Molt4, and PPD-activated normal human T-lymphocytes. The hybrid clone (MP-6) was characterized with regard to expression of markers and lymphokine secretion. The T-T hybridoma was positive for Leu 3a, and thus of T-helper cell lineage. The transferrin receptor (T-9) and the interleukin 2 (IL-2) receptor (Tac) were also expressed as judged by immunofluorescence analysis using monoclonal antibodies. The hybridoma produces B-cell stimulatory factor (BSF) with proliferation and maturation activities, growth inhibitory factor (GIF), leukocyte migration inhibitory factor (LIF) constitutively under serum free conditions, but no detectable interferons (IFN-alpha, IFN-beta, IFN-delta), nor interleukin 2 (IL-2). Weak interleukin 1 (IL-1)-like activity was found. The B-cell stimulatory factor (BSF) induced solid phase-anti-mu triggered resting B-cells obtained from human spleen, tonsil or peripheral blood to proliferate and to secrete IgM and IgG. Without anti-mu triggering the BSF had no proliferation inducing effect. The BSF was characterized and partially purified using ammonium sulphate precipitation, Blue-Sepharose, HPLC hydrophobic interaction and HPLC gel filtration chromatography. The BSF was heat labile at 56 degrees C and was present in two forms, one with high and one with intermediate hydrophobicity. The more hydrophobic form of BSF has a molecular weight of 12K-14K. Kinetic studies of the lymphokine secretion revealed that BSF was produced in detectable amounts in low density (0, 2 X 10(6) cells/ml) 18-24 h cultures. In 48 h to 72 h cultures there was a significant influence of growth inhibitory activities (GIF) produced. GIF, with an apparent MW of 90K could be absorbed out on certain tumor cell lines or on Blue-Sepharose. Further absorption analysis of BSF activities show that anti-mu triggered B-cells but neither resting B-cells nor T-cells could absorb BSF activity.
mesh_terms: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface / Q000276:immunology; D002460:Cell Line; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D003470:Culture Media / Q000032:analysis; D006133:Growth Substances / Q000096:biosynthesis* / Q000378:metabolism; D006801:Humans; D006825:Hybridomas / Q000145:classification / Q000276:immunology / Q000378:metabolism* / Q000648:ultrastructure; D015847:Interleukin-4; D007700:Kinetics; D008213:Lymphocyte Activation / Q000187:drug effects; D008222:Lymphokines / Q000096:biosynthesis* / Q000378:metabolism; D008970:Molecular Weight; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology / Q000378:metabolism* / Q000502:physiology / Q000648:ultrastructure
chemical_list: D000945:Antigens, Differentiation, T-Lymphocyte; D000954:Antigens, Surface; D003470:Culture Media; D006133:Growth Substances; D008222:Lymphokines; D015847:Interleukin-4