Elkins K L, Stashak P W, Baker P J
Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852.
J Immunol. 1990 Apr 15;144(8):2859-64.
Ag-primed B cells must express cell-surface IgM, but not IgD or Ia Ag, and must remain metabolically active, in order to activate suppressor T cells (Ts) specific for type III pneumococcal polysaccharide. Ag-primed B cells that were gamma-irradiated with 1000r, or less, retained the ability to activate Ts; however, Ag-primed B cells exposed to UV light were not able to do so. gamma-Irradiated and UV-treated Ag-primed B cells both expressed comparable levels of cell-surface IgM, and both localized to the spleen after in vivo transfer; neither could proliferate in vitro in response to mitogens. By contrast, gamma-irradiated primed B cells were still able to synthesize proteins, whereas UV-treated primed B cells could not. These findings suggest that in order for Ag-primed B cells to activate Ts, they must a) express cell-associated IgM (sIgM) antibody bearing the idiotypic determinants of antibody specific for type III pneumococcal polysaccharide, and b) be able to synthesize protein for either the continued expression of sIgM after cell transfer, or for the elaboration of another protein molecule that is also required for the activation of Ts; this molecule does not appear to be Ia Ag.
经抗原致敏的B细胞必须表达细胞表面IgM，但不表达IgD或Ia抗原，并且必须保持代谢活性，以便激活针对III型肺炎球菌多糖的特异性抑制性T细胞（Ts）。用1000伦琴或更低剂量γ射线照射的经抗原致敏的B细胞保留了激活Ts的能力；然而，经紫外线照射的经抗原致敏的B细胞则无法做到这一点。经γ射线照射和经紫外线处理的经抗原致敏的B细胞均表达相当水平的细胞表面IgM，并且在体内转移后均定位于脾脏；二者均不能在体外对有丝分裂原作出增殖反应。相比之下，经γ射线照射的致敏B细胞仍能够合成蛋白质，而经紫外线处理的致敏B细胞则不能。这些发现表明，为了使经抗原致敏的B细胞激活Ts，它们必须：a）表达带有针对III型肺炎球菌多糖特异性抗体独特型决定簇的细胞相关IgM（sIgM）抗体，并且b）能够合成蛋白质，用于细胞转移后sIgM的持续表达，或用于合成激活Ts所需的另一种蛋白质分子；该分子似乎不是Ia抗原。
