Recombinant interleukin (IL) 2-induced human B cell differentiation is mediated by autocrine IL6.
The molecular mechanism of the interleukin (IL) 2-induced differentiation of human B cells has been investigated. The experimental results show that Staphylococcus aureus Cowan strain I (SAC) activation alone induces IL6 secretion from B cells. When B cells were activated by SAC, there was an increased transcription of the IL6 mRNA. It reached the peak level by 6 h and rapidly decreased to an undetectable level within 24 h. The IL6 concentration in the culture supernatants reached the peak at 24-48 h and decreased slightly in the following culture periods. Since IL 2 alone could induce IgG secretion, whether exogenous IL6 was added or not, and IL2 did not increase autocrine IL6 synthesis, it appears that IL2 induces the IL6 responsiveness of SAC-activated B cells to differentiate in the later stage of the culture. The addition of polyclonal anti-IL6 antibody inhibited IgG secretion. The antibody still efficiently blocked IgG secretion up to day 5, indicating an important role of autocrine IL6 in the IL2-driven B cell differentiation. However, the saturation dose of anti-IL6 antibody inhibited 50%-70% of IgG secretion, suggesting that IL2-induced B cell differentiation appears to be mediated by other factors besides IL6.
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Laboratory of Cellular Immunology, Alton Ochsner Medical Foundation, New Orleans, LA 70121.
Lee
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Clark
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Choi
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D001402:B-Lymphocytes / Q000166:cytology / Q000502:physiology*; D002454:Cell Differentiation / Q000187:drug effects; D015870:Gene Expression; D006801:Humans; D066298:In Vitro Techniques; D007376:Interleukin-2 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000235:genetics / Q000502:physiology*; D008213:Lymphocyte Activation; D012333:RNA, Messenger / Q000235:genetics; D011994:Recombinant Proteins; D013211:Staphylococcus aureus / Q000276:immunology
D007376:Interleukin-2; D015850:Interleukin-6; D012333:RNA, Messenger; D011994:Recombinant Proteins