Ikeda R, Shinoda T, Kagaya K, Fukazawa Y
Microbiol Immunol. 1984;28(1):51-61. doi: 10.1111/j.1348-0421.1984.tb02946.x.
We investigated the opsonic activity of the serum factors affecting phagocytosis of Cryptococcus neoformans in vitro to elucidate the role of humoral factors in the host defense mechanisms against cryptococcosis. Two strains of C. neoformans, one heavily and one weakly encapsulated, were used. Guinea pig peripheral blood leukocytes (PBLs) were used for phagocytosis. The viable weakly encapsulated cells were ingested effectively by PBLs, in the presence of guinea pig normal fresh serum, while the heavily encapsulated cells were not ingested. Neither immune serum, its IgG fraction alone, nor heated serum promoted the phagocytosis of either the weakly or heavily encapsulated strain. On the other hand, immune serum promoted adherence of PBLs to viable cells of the heavily encapsulated strain, forming rosettes in the presence of fresh serum. A substantial amount of C3b component was detected on yeast cells when weakly encapsulated cells were incubated with human fresh serum, or heavily encapsulated cells were incubated with rabbit immune serum together with human fresh serum. Serum chelation experiments also indicated that the factors involved in the alternative complement pathway are opsonins for the weakly encapsulated strain. These results suggest that the alternative pathway plays an important normal opsonic role for weakly encapsulated strains and that specific antibody plays an immune opsonic role for heavily encapsulated strains of C. neoformans via the classical pathway of complement activation.
我们研究了影响新型隐球菌体外吞噬作用的血清因子的调理活性，以阐明体液因子在宿主抗隐球菌病防御机制中的作用。使用了两株新型隐球菌，一株为厚荚膜菌株，一株为薄荚膜菌株。豚鼠外周血白细胞（PBLs）用于吞噬作用实验。在豚鼠正常新鲜血清存在的情况下，薄荚膜活细胞能被PBLs有效吞噬，而厚荚膜细胞则不被吞噬。免疫血清、其单独的IgG组分或加热血清均不能促进薄荚膜或厚荚膜菌株的吞噬作用。另一方面，免疫血清可促进PBLs与厚荚膜菌株活细胞的黏附，在新鲜血清存在的情况下形成花环。当薄荚膜细胞与人新鲜血清孵育，或厚荚膜细胞与兔免疫血清及人新鲜血清一起孵育时，在酵母细胞上检测到大量C3b成分。血清螯合实验还表明，参与替代补体途径的因子是薄荚膜菌株的调理素。这些结果表明，替代途径对薄荚膜菌株起着重要的正常调理作用，而特异性抗体通过补体激活的经典途径对新型隐球菌厚荚膜菌株起着免疫调理作用。
