Heterogeneity among T helper cells. Interleukin 2 secretion and help for immunoglobulin secretion.
T lymphocytes are thought to provide "help" for B cells by activating them from the resting state, by secretion of antigen-nonspecific lymphokines that promote B cell differentiation and maturation, and by providing signals that induce isotype switching. To clarify the extent to which these different forms of helper activity could be carried out by individual T cells, we set up cultures in which B cells activated, and were in turn themselves stimulated by, limiting numbers of T cells through differences at the H-2 or Mls loci. At T cell doses at which responses were likely to represent the activity of individual helper T cells (or their immediate clonal progeny), we found that some T cells were able both to produce interleukin 2 (IL-2) and to induce secretion of both IgM and IgG, whereas others induced immunoglobulin (Ig) secretion without detectable IL-2 production, and still others made IL-2 but did not promote antibody secretion. We could not detect B cell stimulatory factor 1 production by alloantigen-stimulated T cells, and the addition of antibodies to B cell stimulatory factor 1 did not prevent Ig production. Two results, however--higher Ig accumulation in those wells that received an IL-2-producing cell, and inhibition by anti-IL-2 receptor antibodies of B cell but not T cell function--are consistent with a direct stimulatory effect of IL-2 on B cells in this system. The pattern of helper functions exhibited by T cells freshly isolated from mice differs from that inferred from studies of cloned lines of T cells in long term cultures.
D000818:Animals; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology*; D002999:Clone Cells; D004306:Dose-Response Relationship, Immunologic; D007074:Immunoglobulin G / Q000096:biosynthesis; D007075:Immunoglobulin M / Q000096:biosynthesis; D007376:Interleukin-2 / Q000378:metabolism*; D015847:Interleukin-4; D007378:Interleukins / Q000502:physiology; D008211:Lymphocyte Cooperation; D051379:Mice; D011971:Receptors, Immunologic / Q000502:physiology; D015375:Receptors, Interleukin-2; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007376:Interleukin-2; D007378:Interleukins; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D015847:Interleukin-4