Arala-Chaves M P, Santarém M M, Azevedo C, Soares J O, Granjo E
Bull Eur Physiopathol Respir. 1983 Mar-Apr;19(2):89-98.
Crude extracellular products of the Streptococcus intermedius "CEP-Si" were able to strongly decrease the in vitro proliferation of stimulated human peripheral blood mononuclear cells (HPBMC) when evaluated by (3H)-thymidine and (3H)-leucine uptake. On the other hand, CEP-Si only slightly decreased this proliferation when HPBMC were either not stimulated or cultured in poor conditions or immature cells, i.e. thymocytes were used as target instead. Also in vivo CEP-Si was ineffective when target cells were not highly reactive. Both in vivo and in vitro, the effect of CEP-Si was proportional to the time of contact with the target cells. The dynamics of the effects of CEP-Si suggest the generation of "something" ("suppressor cells") which cause an abrupt drop in the values of (3H)-thymidine uptake rather than a progressive decrease of the values, which could indicate a loss effector or helper cells. On the other hand, CEP-Si suppressed the in vitro primary immunization of human HPBMC against SRBC and, furthermore, human HPBMC incubated with CEP-Si were able to suppress the primary immune response against SRBC of, CEP-Si untreated, HPBMC. In some instances of insufficient time of contact of CEP-Si with the target cells, an enhancement of the immune response was observed both in vivo and in vitro. Moreover, the histological pattern of the spleens of C57 BL/6 mice injected with semipurified products of CEP-Si were consistent with an adjuvant-like effect. Finally, the target HPBMC for the semipurified products of CEP-Si acquired the ultrastructural and antigenic characteristics of suppressor T lymphocytes.
当通过（³H）-胸腺嘧啶核苷和（³H）-亮氨酸摄取进行评估时，中间型链球菌的粗细胞外产物“CEP-Si”能够显著降低体外刺激的人外周血单个核细胞（HPBMC）的增殖。另一方面，当HPBMC未被刺激、在不良条件下培养或使用未成熟细胞（即胸腺细胞作为靶细胞）时，CEP-Si仅轻微降低这种增殖。同样在体内，当靶细胞反应性不高时，CEP-Si也无效。在体内和体外，CEP-Si的作用均与与靶细胞的接触时间成正比。CEP-Si作用的动力学表明产生了“某种物质”（“抑制细胞”），其导致（³H）-胸腺嘧啶核苷摄取值突然下降，而不是值的逐渐降低，后者可能表明效应细胞或辅助细胞的损失。另一方面，CEP-Si抑制了人HPBMC对SRBC的体外初次免疫，此外，与CEP-Si孵育的人HPBMC能够抑制未用CEP-Si处理的HPBMC对SRBC的初次免疫反应。在某些CEP-Si与靶细胞接触时间不足的情况下，在体内和体外均观察到免疫反应增强。此外，注射CEP-Si半纯化产物的C57 BL/6小鼠脾脏的组织学模式与佐剂样作用一致。最后，CEP-Si半纯化产物的靶HPBMC获得了抑制性T淋巴细胞的超微结构和抗原特性。
