紫色杆菌LPS对小鼠脾细胞免疫活性的抑制作用

细菌内毒素或脂多糖(LPS)是机体内强烈的免疫调节剂。天然低毒性紫色杆菌LPS 体内处理小鼠,能促进脾细胞的分化、增殖,但降低脾细胞对 Con A 和同种细菌 LPS 的反应性,抑制混合淋巴细胞反应(MLR)和自然杀伤(NK)细胞的活性。LPS 处理供体小鼠还抑制其脾细胞在 F_1 小鼠内诱导的移植物抗宿主反应。应用混合培养方法,在 Con A和 LPS 诱导的淋巴细胞转化反应中分别检测到非特异性抑制细胞活性,但在MLR和NK 活性测定中未发现抑制细胞的存在。上述结果说明 LPS体内抑制T、B 淋巴细胞功能和 NK细胞活性,而这种抑制作用除由抑制细胞介导外,还存在其它尚未明瞭的机理。

INHIBITION OF IMMUNOLOGICAL RESPONSES OF MOUSE SPLEEN CELLS BY CH. VIOLACEUM ENDOTOXIN ADMINISTERED IN VIVO

Bacterial endotoxins or lipopolysaccharides (LPS) are powerful immunoregulators. Treatment of mice with natural hypotoxic Ch. Violaceum LPS was shown to augment 3H-thymidine uptake of mouse spleen cells, but decrease their proliferative responses to LPS and Con A, and suppress unidirectional mixed lymphocyte reaction (MLR) and natural killer (NK) cell activity. Moreover, treatment of the donor mice with LPS significantly reduced the capacity of their spleen cells to induce graft vs. host reaction in a P→F1 model. In vitro experiments using mixtures of spleen cells from treated and normal mice showed that there existed nonspecific suppressor cell activity in LPS-and Con A-induced lymphocyte transformation reactions but none in MLB and NK activity assays. These results suggested that LPS treatment in vivo had inhibitory effect on B, T lymphocytes and NK cells, which was mediated by suppressor cells and other obscure suppressive mechanisms.