Hanna E E, Watson D W
J Bacteriol. 1968 Jan;95(1):14-21. doi: 10.1128/jb.95.1.14-21.1968.
In rabbits, purified streptococcal pyrogenic exotoxin, at 0.002 of the ld(50) dose, suppressed the antibody response to injected sheep erythrocytes. The antibody suppressed was determined by density gradient ultracentrifugal analysis to be of the 19S class. Background serum antibody (50% hemolytic units), as determined photometrically, correlated well with background antibody-forming spleen cells, as determined by the hemolytic-plaque technique. The exotoxin induced neither positive nor negative changes in background antibody levels, but suppressed the early secondary response to injected antigen. A comparison and control experiment showed that purified gram-negative bacterial endotoxin at identical protocol did not induce antibody suppression, but did induce the well-known adjuvant effect. Because streptococcal pyrogenic exotoxin is known to inhibit the phagocytic function of the reticuloendothelial system (RES), these data strongly support the concept that antigen is processed by cells of the RES before it evokes a secondary immune response. The results also demonstrated that streptococcal pyrogenic exotoxin may play a unique role in lowering the acquired defense of the host against infection. If the anamnestic immune response of the host is temporarily suppressed, then the host-parasite balance would be upset in favor of the parasite.
在兔子中，纯化的链球菌致热外毒素，以半数致死量（LD50）的0.002剂量，抑制了对注射的绵羊红细胞的抗体反应。通过密度梯度超速离心分析确定被抑制的抗体为19S类。通过光度法测定的背景血清抗体（50%溶血单位），与通过溶血空斑技术测定的背景抗体形成脾细胞密切相关。外毒素既未引起背景抗体水平的正向变化，也未引起负向变化，但抑制了对注射抗原的早期二次反应。一项对比和对照实验表明，按照相同方案使用的纯化革兰氏阴性菌内毒素并未诱导抗体抑制，但确实诱导了众所周知的佐剂效应。由于已知链球菌致热外毒素会抑制网状内皮系统（RES）的吞噬功能，这些数据有力地支持了以下概念：抗原在引发二次免疫反应之前由RES细胞进行处理。结果还表明，链球菌致热外毒素可能在降低宿主对感染的后天防御方面发挥独特作用。如果宿主的回忆性免疫反应被暂时抑制，那么宿主与寄生虫之间的平衡将被打破，有利于寄生虫。
