Santarém M M, Porto M T, Ferreira P, Soares R, Arala-Chaves M P
Department of Immunology, Institute for Biomedical Sciences Abel Salazar, Porto, Portugal.
Scand J Immunol. 1987 Dec;26(6):755-61. doi: 10.1111/j.1365-3083.1987.tb02313.x.
Crude extracellular products of Streptococcus mutans (CEP-Sm) suppress the proliferative response to phytohaemagglutinin of human peripheral blood mononuclear cells and the primary immune response of C57BL/6 mice to sheep erythrocytes. This immunosuppressive effect favours the survival of the microorganism, and the bacteria lose the ability to secrete immunosuppressor substance if previously subcultured several times. Cells incubated with CEP-Sm and subsequently washed recover the ability to proliferate. Traces of CEP-Sm or to short a time of contact between CEP-Sm and the target immune system induced higher proliferative ratios or higher in vivo immune responses than controls, respectively. The proliferative values of cultures supplemented with CEP-Sm were parallel to the control values up to a certain time, after which they dropped abruptly. This drop is followed by a proliferation, and the higher the amount of CEP-Sm added to the cultures, the shorter the time until the proliferation. CEP-Sm was fractionated by means of ion exchange chromatography followed by double preparative isoelectrofocusing, ending in a subfraction of isoelectric point between 3.9 and 4.2, containing a heat-unstable material stainable by Coomassie blue but unstainable by periodic acid Schiff or methylene blue, and having a maximum optical density of 280 nm.
变形链球菌的粗细胞外产物（CEP-Sm）可抑制人外周血单核细胞对植物血凝素的增殖反应以及C57BL/6小鼠对绵羊红细胞的初次免疫反应。这种免疫抑制作用有利于该微生物的存活，并且如果之前多次传代培养，细菌会失去分泌免疫抑制物质的能力。用CEP-Sm孵育细胞并随后洗涤后，细胞恢复增殖能力。与对照组相比，痕量的CEP-Sm或CEP-Sm与靶免疫系统之间较短的接触时间分别诱导出更高的增殖率或更高的体内免疫反应。在一定时间之前，添加CEP-Sm的培养物的增殖值与对照值平行，之后它们会突然下降。这种下降之后会出现增殖，并且添加到培养物中的CEP-Sm量越高，直到增殖的时间越短。通过离子交换色谱法对CEP-Sm进行分级分离，然后进行两次制备性等电聚焦，最终得到一个等电点在3.9至4.2之间的亚组分，该亚组分含有一种热不稳定物质，可被考马斯亮蓝染色，但不能被过碘酸希夫试剂或亚甲蓝染色，并且在280nm处具有最大光密度。
