Pittner B T, Snow E C
Department of Microbiology and Immunology, University of Kentucky Medical Center, Lexington 40536-0084, USA.
Cell Immunol. 1998 May 25;186(1):55-62. doi: 10.1006/cimm.1998.1292.
Cycling, splenic B cells were recultured with: (1) no stimulant to reflect poorly competitive clones; (2) soluble, whole anti-mu to reflect clones that bind soluble immune complexes; (3) soluble F(ab')2 anti-mu to reflect clones that bind soluble antigen; and (4) immobilized anti-mu to reflect clones that bind antigen presented by FDC. All four groups displayed similar levels of the death proteins Bax and Bcl-xS. In contrast, cycling B cells restimulated with either soluble F(ab')2 or immobilized anti-mu expressed heightened levels of the survival protein Bcl-xL, and only cells restimulated with immobilized anti-mu expressed the survival protein Bcl-2. Cycling B cells restimulated with either soluble F(ab')2 or immobilized anti-mu displayed a selective survival advantage over cycling B cells receiving no stimulus or soluble, whole anti-mu by both enhancing their responsiveness to CD40 ligand, a Th-cell-derived signal, and increasing the period that the cycling B cells remained responsive to this Th-cell-derived signal. The Th-cell-derived signal did not appreciably alter cycling B cell expression of Bcl-2 family members.
循环过程中，脾B细胞与以下物质进行再培养：(1) 无刺激物，以反映竞争力较弱的克隆；(2) 可溶性全抗μ，以反映结合可溶性免疫复合物的克隆；(3) 可溶性F(ab')2抗μ，以反映结合可溶性抗原的克隆；(4) 固定化抗μ，以反映结合FDC呈递抗原的克隆。所有四组均显示出相似水平的死亡蛋白Bax和Bcl-xS。相比之下，用可溶性F(ab')2或固定化抗μ再次刺激的循环B细胞表达的存活蛋白Bcl-xL水平升高，且只有用固定化抗μ再次刺激的细胞表达存活蛋白Bcl-2。用可溶性F(ab')2或固定化抗μ再次刺激的循环B细胞通过增强其对CD40配体（一种Th细胞衍生信号）的反应性，并延长循环B细胞对这种Th细胞衍生信号保持反应性的时间，相对于未接受刺激或接受可溶性全抗μ的循环B细胞显示出选择性存活优势。Th细胞衍生信号并未明显改变循环B细胞中Bcl-2家族成员的表达。
