Tohma S, Lipsky P E
Harold C. Simmons Arthritis Research Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas 75235.
J Immunol. 1991 Apr 15;146(8):2544-52.
Coculture of resting human B cells with T cells stimulated with immobilized mAb to the CD3 molecular complex induces polyclonal activation and the production of Ig of all isotypes. The current experiments were carried out to determine the nature of the signals provided to B cells by the anti-CD3-activated T cells. For these experiments, fresh T cells or T cell clones were activated with immobilized mAb to CD3 and then fixed with 1% paraformaldehyde. Upon coculture, the fixed activated T cells or T cell clones induced B cell RNA synthesis and IL-2R expression, but only minimal DNA synthesis and no Ig production. Induction of B cell RNA synthesis by fixed activated T cells was not inhibited by mAb to the alpha-chain of the IL-2R, and was not enhanced by supplementing cultures with IL-2, IL-4, IL-6, or supernatants of mitogen-activated T cells. Upon the addition of IL-2, but not IL-4 or IL-6, to cultures of B cells and fixed activated T cells, sustained proliferation was noted along with the production of Ig. Control fixed T cells or T cell clones did not induce any of these responses. The presence of cycloheximide or cyclosporin A during the activation with anti-CD3 prevented T cells from developing the capacity to provide help for B cells. The use of mAb to a variety of cell surface molecules indicated that several T cell surface molecules including CD11a/CD18, CD44, CD54, and class I MHC molecules are involved in the induction of B cell responses. Among the mAb that inhibited B cell DNA synthesis and/or Ig production, only mAb to CD11a, CD18, or CD54 inhibited initial B cell activation as assessed by RNA synthesis. Even though mAB to CD11a/CD18 inhibited the capacity of fixed activated T cells to induce B cell responses, the finding that fixed activated CD18 deficit clones provided help for B cells indicated that expression of the beta 2 family of integrins by T cells was not necessary. These results indicate that activated T cells acquire the capacity to stimulate B cells polyclonally and induce cytokine responsiveness, proliferation, and Ig production by utilization of a variety of surface molecules. Moreover, these results indicate that the initial activation of the B cell is independent of the metabolic activity of the T cell and the production of cytokines.
将静息的人B细胞与用固定化抗CD3分子复合物单克隆抗体刺激的T细胞共培养，可诱导多克隆激活并产生所有同种型的Ig。进行当前实验以确定抗CD3激活的T细胞向B细胞提供的信号的性质。对于这些实验，新鲜的T细胞或T细胞克隆用固定化抗CD3单克隆抗体激活，然后用1%多聚甲醛固定。共培养时，固定的活化T细胞或T细胞克隆诱导B细胞RNA合成和IL-2R表达，但仅诱导极少的DNA合成且不产生Ig。固定的活化T细胞诱导的B细胞RNA合成不受抗IL-2Rα链单克隆抗体的抑制，并且通过向培养物中补充IL-2、IL-4、IL-6或丝裂原激活的T细胞的上清液也不会增强。在B细胞和固定的活化T细胞培养物中加入IL-2而非IL-4或IL-6时，可观察到持续增殖以及Ig的产生。对照固定的T细胞或T细胞克隆未诱导任何这些反应。在用抗CD3激活过程中存在放线菌酮或环孢菌素A可阻止T细胞发展为向B细胞提供帮助的能力。使用针对多种细胞表面分子的单克隆抗体表明，包括CD11a/CD18、CD44、CD54和I类MHC分子在内的几种T细胞表面分子参与了B细胞反应的诱导。在抑制B细胞DNA合成和/或Ig产生的单克隆抗体中，只有抗CD11a、CD18或CD54的单克隆抗体抑制通过RNA合成评估的初始B细胞激活。尽管抗CD11a/CD18单克隆抗体抑制了固定的活化T细胞诱导B细胞反应的能力，但固定的活化CD18缺陷克隆向B细胞提供帮助的发现表明T细胞整合素β2家族的表达并非必需。这些结果表明，活化的T细胞通过利用多种表面分子获得了多克隆刺激B细胞并诱导细胞因子反应性、增殖和Ig产生的能力。此外，这些结果表明B细胞的初始激活独立于T细胞的代谢活性和细胞因子的产生。
