Clement L T, Dagg M K, Lehmeyer J E, Kiyotaki M
J Immunol. 1983 Sep;131(3):1214-7.
Human B lymphocytes can be induced to differentiate into antibody-secreting plasma cells by Leu-3+ T lymphocytes stimulated with pokeweed mitogen (PWM), a polyclonal T cell activator. In contrast, other polyclonal T cell mitogens, such as phytohemagglutinin (PHA), also activate Leu-3+ T cells but are relatively ineffective inducers of B cell differentiation. We have performed a series of experiments to investigate the mechanism underlying this apparent paradox. When human B cells were cultured with unfractionated T cells and PWM or PHA, only PWM was able to induce plasma cell formation and immunoglobulin (Ig) secretion. However, when the T cells were treated with mitomycin C (MMC) before culture, both PWM and PHA were able to induce significant B cell differentiation. These data indicated that both mitogens were able to activate the helper T cells required for B lymphocyte differentiation and suggested that MMC-sensitive suppressor T cells were responsible for inhibiting the induction of antibody-secreting cells by MMC-untreated T cells stimulated with PHA. Phenotypic analysis of the T cells capable of suppressing PHA-induced B cell differentiation revealed that small numbers of either Leu-2+ or Leu-3+ T cells could profoundly suppress the B cell differentiation induced by PHA. In contrast, significant suppression of PWM-stimulated B cell differentiation was observed only with relatively large numbers of Leu-2+ T cells. These data confirm previous reports that OKT4+/Leu-3+ T cells can suppress human B cell differentiation and indicate that the difference in B cell differentiation induced by PWM and PHA with MMC-untreated T cells is largely a reflection of the relative potency of these mitogens to activate these phenotypically distinct suppressor T cell subpopulations.
人B淋巴细胞可被用美洲商陆丝裂原（PWM，一种多克隆T细胞激活剂）刺激的Leu - 3⁺ T淋巴细胞诱导分化为分泌抗体的浆细胞。相比之下，其他多克隆T细胞丝裂原，如植物血凝素（PHA），也能激活Leu - 3⁺ T细胞，但在诱导B细胞分化方面相对无效。我们进行了一系列实验来研究这一明显矛盾背后的机制。当人B细胞与未分离的T细胞以及PWM或PHA一起培养时，只有PWM能够诱导浆细胞形成和免疫球蛋白（Ig）分泌。然而，当T细胞在培养前用丝裂霉素C（MMC）处理时，PWM和PHA都能够诱导显著的B细胞分化。这些数据表明两种丝裂原都能够激活B淋巴细胞分化所需的辅助性T细胞，并提示MMC敏感的抑制性T细胞负责抑制由PHA刺激的未用MMC处理的T细胞诱导的抗体分泌细胞的产生。对能够抑制PHA诱导的B细胞分化的T细胞进行表型分析发现，少量的Leu - 2⁺或Leu - 3⁺ T细胞都能显著抑制PHA诱导的B细胞分化。相比之下，只有相对大量的Leu - 2⁺ T细胞才能观察到对PWM刺激的B细胞分化的显著抑制。这些数据证实了先前的报道，即OKT4⁺/Leu - 3⁺ T细胞可以抑制人B细胞分化，并表明PWM和PHA与未用MMC处理的T细胞诱导的B细胞分化差异在很大程度上反映了这些丝裂原激活这些表型不同的抑制性T细胞亚群的相对能力。
