Gordon J, Millsum M J, Guy G R, Ledbetter J A
Department of Immunology, University of Birmingham, UK.
J Immunol. 1988 Mar 1;140(5):1425-30.
Resting tonsillar B lymphocytes were shown to enlarge and become more buoyant when exposed to either IL-4 or a mAb (G28-5) to the 50-kDa CDw40 Ag. A striking feature of activation through CDw40 was the promotion of strong homotypic adhesions which did not occur in populations cultured with IL-4. Whereas the CDw40 antibody down-regulated its target Ag, an increased expression of CDw40 accompanied IL-4 stimulation. Similarly, only IL-4, and not the CDw40 antibody, was able to induce the appearance of CD23 on the resting B cell surface. Functionally, the major consequence of ligating CDw40 on resting B cells was that they remained alert to subsequent mitogenic signaling--cells incubated with IL-4 developed the same sluggish response as noted in control cultures. Together, IL-4 and the CDw40 antibody provoked a small, but significant, level of DNA synthesis in tonsillar B cells which was enhanced dramatically by the inclusion of low m.w. B cell growth factor. This latter agent had no discernible direct effect on resting B lymphocytes. The different pathways which have been observed for triggering resting B cells are discussed.
研究表明，静息的扁桃体B淋巴细胞在暴露于白细胞介素-4（IL-4）或针对50-kDa CDw40抗原的单克隆抗体（G28-5）时会增大并变得更具浮力。通过CDw40激活的一个显著特征是促进了强烈的同型黏附，而在用IL-4培养的细胞群体中并未出现这种情况。虽然CDw40抗体下调了其靶抗原，但CDw40的表达在IL-4刺激下会增加。同样，只有IL-4而非CDw40抗体能够诱导静息B细胞表面出现CD23。在功能上，连接静息B细胞上的CDw40的主要后果是它们对随后的促有丝分裂信号保持警觉——用IL-4培养的细胞产生的反应与对照培养物中观察到的一样迟缓。总之，IL-4和CDw40抗体在扁桃体B细胞中引发了少量但显著的DNA合成水平，通过加入低分子量B细胞生长因子可使其显著增强。后一种因子对静息B淋巴细胞没有明显的直接作用。本文讨论了已观察到的触发静息B细胞的不同途径。
