Ben-Nun A, Yossefi S
Department of Cell Biology, Weizmann Institute of Science, Rehovot, Israel.
Eur J Immunol. 1992 Jun;22(6):1495-503. doi: 10.1002/eji.1830220623.
Staphylococcal enterotoxins have long been known to be powerful stimulators of T lymphocytes in mouse and man. In a previous study we showed that high concentrations of staphylococcal enterotoxin serotype B (SEB) failed to stimulate strong proliferative responses by Lewis rat T lymphocytes. Moreover, concentrations of SEB (10-50 micrograms/ml) that stimulated optimal mouse T lymphocyte proliferative responses suppressed a mitogen- or antigen-induced rat T lymphocytes proliferative responses. The present study shows that SEB at low concentrations (as low as 10(-3)-10(-4) micrograms/ml) and often also trace levels (about 10(-6)-10(-7) micrograms/ml) suppresses both rat and mouse T lymphocytes proliferative responses to mitogen or antigen. Furthermore, under different circumstances, SEB may have conflicting effects on the same T cells. While high concentrations (1-50 micrograms/ml) of SEB stimulate certain mouse T cell clones, low concentrations or trace levels have a potent suppressive effect on the same clones. The results indicate that the in vitro conflicting effects of SEB on the same T cells are concentration dependent and may reflect its in vivo effects on SEB-reactive T lymphocytes. The suppression of the mitogen- or antigen-induced stimulation of T cell clones by SEB was direct and did not require the agency of suppressor cells. Furthermore, the suppression by low amounts of SEB was not major histocompatibility complex restricted and affected a large proportion of both rat and mouse T lymphocyte subpopulation, regardless of their antigenic specificity. The concomitant suppressogenic and stimulatory characteristics of SEB support the conclusion that, under different conditions, SEB can be considered a "super-suppressogen" as well as a "super-antigen". Overall, the results suggest that SEB, and possibly other bacterial toxins, could be useful in immunomodulation of specific T cell responses.
长期以来，人们一直认为葡萄球菌肠毒素是小鼠和人类T淋巴细胞的强大刺激剂。在先前的一项研究中，我们发现高浓度的B型葡萄球菌肠毒素（SEB）无法刺激Lewis大鼠T淋巴细胞产生强烈的增殖反应。此外，能刺激小鼠T淋巴细胞产生最佳增殖反应的SEB浓度（10 - 50微克/毫升）会抑制有丝分裂原或抗原诱导的大鼠T淋巴细胞增殖反应。本研究表明，低浓度（低至10^(-3) - 10^(-4)微克/毫升）的SEB，而且通常痕量水平（约10^(-6) - 10^(-7)微克/毫升）也会抑制大鼠和小鼠T淋巴细胞对有丝分裂原或抗原的增殖反应。此外，在不同情况下，SEB对同一T细胞可能有相互矛盾的作用。虽然高浓度（1 - 50微克/毫升）的SEB能刺激某些小鼠T细胞克隆，但低浓度或痕量水平对同一克隆有强大的抑制作用。结果表明，SEB在体外对同一T细胞的矛盾作用是浓度依赖性的，可能反映了其在体内对SEB反应性T淋巴细胞的作用。SEB对T细胞克隆有丝分裂原或抗原诱导刺激的抑制是直接的，不需要抑制细胞的作用。此外，少量SEB的抑制作用不受主要组织相容性复合体限制，并且影响大鼠和小鼠T淋巴细胞亚群的很大一部分，无论其抗原特异性如何。SEB同时具有抑制和刺激特性，支持了以下结论：在不同条件下，SEB既可以被视为“超级抑制原”，也可以被视为“超级抗原”。总体而言，结果表明SEB以及可能的其他细菌毒素可用于特异性T细胞反应的免疫调节。
