Kozel T R, Tabuni A, Young B J, Levitz S M
Department of Microbiology and the Cell and Molecular Biology Program, University of Nevada, Reno, 89557, USA.
Infect Immun. 1996 Jun;64(6):2336-8. doi: 10.1128/iai.64.6.2336-2338.1996.
Previous studies demonstrated that, following opsonization with normal human serum (NHS), phagocytes bind greater numbers of small-capsule Cryptococcus neoformans cells than yeast cells with large capsules. The present study tested the hypothesis that suboptimal deposition of opsonic C3 fragments contributes to this disparity. C neoformans was grown under conditions promoting large or small capsules and was incubated at various concentrations in NHS. At low concentrations of yeast cells (125 cells per microl of NHS), the deposition of C3 fragments per unit of capsule volume and the binding of yeast cells to cultured human monocytes were similar for yeast cells having large and small capsules. However, at higher cell concentrations, large-capsule cells exhibited suboptimal coating with C3 fragments and markedly diminished monocyte binding compared with small-capsule cells. Thus, the inverse correlation between capsule size and phagocyte binding can be overcome by conditions promoting optimal C3 deposition.
先前的研究表明，用正常人血清（NHS）进行调理作用后，吞噬细胞结合的小荚膜新型隐球菌细胞数量比大荚膜酵母细胞更多。本研究检验了以下假设：调理素C3片段的次优沉积导致了这种差异。新型隐球菌在促进形成大或小荚膜的条件下生长，并在NHS中以不同浓度孵育。在低浓度酵母细胞（每微升NHS中有125个细胞）时，大、小荚膜酵母细胞每单位荚膜体积的C3片段沉积以及酵母细胞与培养的人单核细胞的结合情况相似。然而，在较高细胞浓度下，与小荚膜细胞相比，大荚膜细胞表现出C3片段的次优包被，且单核细胞结合明显减少。因此，通过促进最佳C3沉积的条件，可以克服荚膜大小与吞噬细胞结合之间的负相关关系。
