Blackstock R, McCormack J M, Hall N K
Infect Immun. 1987 Jan;55(1):233-9. doi: 10.1128/iai.55.1.233-239.1987.
Soluble extracts of Cryptococcus neoformans were examined for their ability to induce a macrophage-regulatory T-suppressor cell known to appear in the spleens of mice infected with cryptococci. Suppressor cells were induced by injection of extracts of encapsulated or thinly encapsulated strains of cryptococci. Dose-response analysis showed that as little as 25 micrograms of soluble capsular polysaccharide antigen could induce significant suppressor cell activity, with maximum suppression occurring at a dose of 100 micrograms. The suppressor cells appeared within 1 week of injection of antigen and persisted for at least 2 months. Suppressor cells were induced in animals given tolerogenic doses of levan, human gamma globulin, and soluble capsular polysaccharide antigen. When these same antigens were administered in immunogenic form, no suppressor cell activity was detected. Therefore, the suppressive mechanism was common to models of immunologic tolerance and was not unique to cryptococcal disease or cryptococcal capsular polysaccharide antigen. The phagocytosis-inhibiting lymphokine produced by the suppressor cell population completely inhibited the phagocytic activity of only a portion of peritoneal exudate cells. Other macrophages in the population were not totally inhibited but exhibited a reduction in the number of yeast cells engulfed.
对新型隐球菌的可溶性提取物进行了检测，以考察其诱导巨噬细胞调节性T抑制细胞的能力，已知这种细胞会出现在感染隐球菌的小鼠脾脏中。通过注射包膜型或薄包膜型隐球菌菌株的提取物可诱导产生抑制细胞。剂量反应分析表明，低至25微克的可溶性荚膜多糖抗原就能诱导出显著的抑制细胞活性，在100微克剂量时抑制作用达到最大。抑制细胞在注射抗原后1周内出现，并持续至少2个月。在给予致耐受性剂量的左聚糖、人γ球蛋白和可溶性荚膜多糖抗原的动物中可诱导产生抑制细胞。当以免疫原性形式给予这些相同抗原时，未检测到抑制细胞活性。因此，这种抑制机制在免疫耐受模型中很常见，并非新型隐球菌病或新型隐球菌荚膜多糖抗原所特有。抑制细胞群体产生的抑制吞噬作用的淋巴因子仅完全抑制了一部分腹腔渗出细胞的吞噬活性。群体中的其他巨噬细胞并未被完全抑制，但吞噬的酵母细胞数量有所减少。
