Ochs H D, Wedgwood R J, Frank M M, Heller S R, Hosea S W
Clin Exp Immunol. 1983 Jul;53(1):208-16.
To determine the effect of complement on the normal antibody response to T cell-dependent antigens, we immunized normal and C4 deficient guinea-pigs with bacteriophage phi X 174. Following primary immunization with a standard dose (2 X 10(9) PFU/Kg) given intravenously. C4 deficient guinea-pigs produced less antibody than normal guinea-pigs and were unable to maintain measurable antibody levels. Following secondary immunization, antigen clearance of C4 deficient guinea-pigs was delayed and the subsequent antibody response was identical to their primary response without amplification or isotype switch. Increased antigen dose and administration of antigen in adjuvants into footpads improved the responses but did not make them normal. The primary and secondary responses became essentially normal, however, when small amounts of normal guinea-pig serum were given to the deficient animals at the time of the primary (but not the secondary) immunization. We postulate that the contribution of complement to the mature humoral immune response is related to activation of C3. Our data show that antigen initiates a primary immune response. The resultant antigen-antibody complexes interact with complement and are then non-specifically trapped by C3 receptors on dendritic cells, B cells and macrophages. Thus, antigen is selectively accumulated within the lymphoid organs and in turn 'captures' antigen specific B cells by interaction of the trapped antigen with antigen specific sIg. The approximation of specific lymphoid cells, macrophages and antigen permits generation of specific memory cells and ensures prompt, mature antibody response on subsequent antigen exposure.
为了确定补体对针对T细胞依赖性抗原的正常抗体反应的影响，我们用噬菌体φX 174免疫正常和C4缺陷型豚鼠。静脉注射标准剂量（2×10⁹ PFU/Kg）进行初次免疫后，C4缺陷型豚鼠产生的抗体比正常豚鼠少，且无法维持可测量的抗体水平。二次免疫后，C4缺陷型豚鼠的抗原清除延迟，随后的抗体反应与其初次反应相同，没有扩增或同种型转换。增加抗原剂量以及将抗原与佐剂一起注射到脚垫中可改善反应，但未使其恢复正常。然而，在初次（而非二次）免疫时给缺陷动物注射少量正常豚鼠血清后，初次和二次反应基本恢复正常。我们推测补体对成熟体液免疫反应的贡献与C3的激活有关。我们的数据表明，抗原引发初次免疫反应。产生的抗原 - 抗体复合物与补体相互作用，然后被树突状细胞、B细胞和巨噬细胞上的C3受体非特异性捕获。因此，抗原选择性地在淋巴器官内积聚，进而通过捕获的抗原与抗原特异性表面免疫球蛋白的相互作用“捕获”抗原特异性B细胞。特异性淋巴细胞、巨噬细胞和抗原的接近允许产生特异性记忆细胞，并确保在随后接触抗原时迅速产生成熟的抗体反应。
