Ferrante A, Rowan-Kelly B, Paton J C
Infect Immun. 1984 Nov;46(2):585-9. doi: 10.1128/iai.46.2.585-589.1984.
The effects of pneumolysin, a sulfhydryl-activated cytolytic toxin produced by Streptococcus pneumoniae, on the in vitro human lymphocyte response was examined. The toxin, at concentrations of one to five hemolytic units per ml, caused marked inhibition of the response of lymphocytes to concanavalin A, phytohemagglutinin, pokeweed mitogen, and protein A. The response was assessed by measuring both [3H]thymidine incorporation and the ability of lymphocytes to produce immunoglobulins and lymphokine activity. The effects of pneumolysin were irreversible, could be prevented by pretreatment of the toxin with cholesterol, and were not related to a direct cytotoxic effect on the lymphocytes. Pneumolysin appeared to act at the initiation phase of the immune response and had no effect on lymphocytes committed to DNA synthesis or to the synthesis and secretion of immunoglobulins. Furthermore, pneumolysin-mediated inhibition of the lymphocyte response was not due to the inhibition of binding of mitogens to leukocytes and is likely to be related to effects on membrane-mediated signals essential for lymphocyte triggering. This may be one means by which pneumolysin plays a role in the pathogenesis of pneumococcal infections.
研究了肺炎链球菌产生的一种巯基激活的溶细胞毒素——肺炎溶血素对体外人淋巴细胞反应的影响。该毒素浓度为每毫升1至5个溶血单位时，可显著抑制淋巴细胞对刀豆球蛋白A、植物血凝素、商陆有丝分裂原和蛋白A的反应。通过测量[³H]胸腺嘧啶核苷掺入以及淋巴细胞产生免疫球蛋白和淋巴因子活性的能力来评估反应。肺炎溶血素的作用是不可逆的，用胆固醇预处理毒素可防止这种作用，且其作用与对淋巴细胞的直接细胞毒性作用无关。肺炎溶血素似乎在免疫反应的起始阶段起作用，对已进行DNA合成或免疫球蛋白合成与分泌的淋巴细胞没有影响。此外，肺炎溶血素介导的淋巴细胞反应抑制并非由于有丝分裂原与白细胞结合的抑制，可能与对淋巴细胞触发所必需的膜介导信号的影响有关。这可能是肺炎溶血素在肺炎球菌感染发病机制中发挥作用的一种方式。
