title: A human CD4- T cell leukemia subclone with contact-dependent helper function.
abstract: Helper T lymphocytes provide a contact dependent signal to resting B cells that is required for optimal differentiation into Ig-secreting cells. The surface structure(s) on T cells that mediate helper function have not been identified but are known to be induced by T cell activation. A CD4- subclone of the Jurkat leukemic T cell line (D1.1) was isolated and found to be distinct from CD4+ Jurkat clones and a variety of other T and non-T cell leukemic lines in that coculture of D1.1 with resting B cells induced B cells to specifically express surface CD23 molecules, a marker of B cell activation. Furthermore, Jurkat D1.1 induced B cell proliferation and terminal B cell differentiation into IgG-secreting cells in the presence of T cell-dependent B cell mitogens. Similar to the helper effector function of activated T cells, the effects of Jurkat D1.1 were neither Ag nor MHC restricted. Paraformaldehyde fixed Jurkat D1.1 cells remained competent to activate B cells while D1.1 supernatants and diffusible factors were inactive. The effect of Jurkat D1.1 on B cell activation was distinct from that of rIL-4 and was not inhibited by antibodies to IL-4. Together these observations suggested that surface structures on D1.1 and not secreted factors, mediated contact-dependent helper effector function.
authors.affiliation: Department of Medicine, Columbia University, New York, NY 10032.
authors.forename: M J
authors.initials: MJ
authors.lastname: Yellin
authors.forename: J J
authors.initials: JJ
authors.lastname: Lee
authors.forename: L
authors.initials: L
authors.lastname: Chess
authors.forename: S
authors.initials: S
authors.lastname: Lederman
mesh_terms: D015703:Antigens, CD / Q000032:analysis; D000944:Antigens, Differentiation, B-Lymphocyte / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000032:analysis; D001402:B-Lymphocytes / Q000276:immunology*; D015704:CD4 Antigens / Q000276:immunology; D002999:Clone Cells; D005434:Flow Cytometry; D006801:Humans; D015847:Interleukin-4 / Q000502:physiology; D015458:Leukemia, T-Cell / Q000276:immunology*; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D016685:Mitomycin / Q000494:pharmacology; D011947:Receptors, Antigen, B-Cell / Q000502:physiology; D011961:Receptors, Fc / Q000276:immunology; D017455:Receptors, IgE; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*; D014407:Tumor Cells, Cultured
chemical_list: D015703:Antigens, CD; D000944:Antigens, Differentiation, B-Lymphocyte; D000945:Antigens, Differentiation, T-Lymphocyte; D015704:CD4 Antigens; D011947:Receptors, Antigen, B-Cell; D011961:Receptors, Fc; D017455:Receptors, IgE; D015847:Interleukin-4; D016685:Mitomycin