The direct effects of interleukin 1, interleukin 2, interferon-alpha, interferon-gamma, B-cell growth factor, and a B-cell differentiation factor on resting and activated human B cells.
A wide variety of cytokines have been demonstrated to affect B-cell function. However, it is unclear which of these mediators actually exert direct effects on the B cells themselves. In the present study, the direct role of interleukin (IL) 1, IL-2, Interferon-gamma, or Interferon-alpha in human B-cell activation, proliferation, or differentiation was examined and compared with the effects of a B-cell growth factor (BCGF) or a B-cell differentiation factor (BCDF). Highly purified human B lymphocytes were separated according to size into two nonoverlapping populations. The fraction of small B cells was incubated with IL-1, IL-2, Interferon-gamma, Interferon-alpha, BCGF, or BCDF, and cell size changes, RNA synthesis, DNA synthesis, or supernatant immunoglobulin (Ig) production were measured. Neither IL-1, IL-2, Interferon-alpha, Interferon-gamma, nor the BCGF induced substantial cell size changes, RNA synthesis, DNA synthesis, or Ig production by the small fraction of B lymphocytes; however, the BCDF could directly activate a proportion of resting B lymphocytes to secrete Ig. The fraction of large B cells was also incubated with these cytokines. While neither IL-1, Interferon-alpha, nor Interferon-gamma enhanced DNA synthesis or Ig production by the fraction of large B lymphocytes, DNA synthesis was augmented 23-fold by BCGF and IgG production was increased 7-fold by BCDF. Additionally, IL-2 slightly enhanced both proliferation and differentiation of large B cells but substantially less so than BCGF and BCDF; DNA synthesis was increased 4-fold, while Ig production in the presence of IL-2 was increased by approximately 50%. Thus, the most important lymphokines modulating the function of these two fractions of tonsillar lymphocytes were a BCGF and a BCDF.
D001402:B-Lymphocytes / Q000166:cytology* / Q000276:immunology / Q000378:metabolism; D006133:Growth Substances / Q000502:physiology*; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis; D007370:Interferon Type I / Q000494:pharmacology*; D007371:Interferon-gamma / Q000494:pharmacology*; D007375:Interleukin-1 / Q000502:physiology*; D007376:Interleukin-2 / Q000378:metabolism / Q000502:physiology*; D015847:Interleukin-4; D007399:Interphase; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000502:physiology*; D014066:Palatine Tonsil; D012313:RNA / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000494:pharmacology / Q000502:physiology
D006133:Growth Substances; D007136:Immunoglobulins; D007370:Interferon Type I; D007375:Interleukin-1; D007376:Interleukin-2; D008222:Lymphokines; D011994:Recombinant Proteins; D015847:Interleukin-4; D012313:RNA; D007371:Interferon-gamma