Mayumi M, Kuritani T, Kubagawa H, Cooper M D
J Immunol. 1983 Feb;130(2):671-7.
The human IgG subclasses expressed by circulating B lymphocytes, tissue plasma cells, and plasma cells generated from B cell precursors in response to the polyclonal mitogens LPS and PWM were examined by immunofluorescence using subclass-specific monoclonal antibodies. The subclass distribution observed for circulating B lymphocytes was IgG2 (48%) greater than IgG1 (40%) greater than IgG3 (8%) greater than IgG4 (1%), while the distribution among IgG plasma cells in bone marrow, blood, spleen, and tonsils was IgG1 (64%) greater than IgG2 (26%) greater than IgG3 (8%) greater than IgG4 (1%). Multiple IgG isotypes were not observed on B cells or in plasma cells. Although IgG plasma cell responses to both LPS and PWM were T cell dependent, the distributions of IgG subclasses elicited were strikingly different. In control and LPS-stimulated cultures of blood mononuclear cells, the induced plasma cells expressed the IgG subclass distribution: IgG2 greater than 80%, IgG1 less than 20%, IgG3 less than 1%, IgG4 less than 1%. In PWM-stimulated cultures, the subclass distribution, IgG1 approximately 65%, IgG2 approximately 25%, IgG3 approximately 7%, IgG4 approximately 1%, was in perfect concordance with the in vivo subclass distribution of IgG plasma cells. Selective inhibition of suppressor T cell activity by x-irradiation and mitomycin C treatment did not alter the IgG subclass distribution pattern induced by LPS and PWM. Monoclonal antibodies were used to deplete selectively the B cell precursors bearing IgG1, IgG2, or IgG3 before PWM stimulation of blood mononuclear cells. In each instance, a reduction was observed only in the subpopulation of plasma cells producing the homologous IgG subclass. The results indicate that T cells can preferentially influence the terminal differentiation of B cells that are precommitted to different IgG subclasses.
利用亚类特异性单克隆抗体，通过免疫荧光法检测了循环B淋巴细胞、组织浆细胞以及B细胞前体在多克隆丝裂原脂多糖（LPS）和美洲商陆有丝分裂原（PWM）刺激下产生的浆细胞所表达的人IgG亚类。循环B淋巴细胞中观察到的亚类分布为IgG2（48%）＞IgG1（40%）＞IgG3（8%）＞IgG4（1%），而在骨髓、血液、脾脏和扁桃体的IgG浆细胞中的分布为IgG1（64%）＞IgG2（26%）＞IgG3（8%）＞IgG4（1%）。在B细胞或浆细胞上未观察到多种IgG同种型。尽管IgG浆细胞对LPS和PWM的反应均依赖T细胞，但所诱导的IgG亚类分布却显著不同。在血液单核细胞的对照和LPS刺激培养物中，诱导产生的浆细胞表达的IgG亚类分布为：IgG2＞80%，IgG1＜2%，IgG3＜1%，IgG4＜1%。在PWM刺激的培养物中，亚类分布为IgG1约65%，IgG2约25%，IgG3约7%，IgG4约1%，与体内IgG浆细胞的亚类分布完全一致。用X射线照射和丝裂霉素C处理选择性抑制抑制性T细胞活性，并未改变LPS和PWM诱导的IgG亚类分布模式。在对血液单核细胞进行PWM刺激之前，使用单克隆抗体选择性清除携带IgG1、IgG2或IgG3的B细胞前体。在每种情况下，仅观察到产生同源IgG亚类的浆细胞亚群减少。结果表明，T细胞可优先影响预先定向分化为不同IgG亚类的B细胞的终末分化。
