Green E M, Armstrong S J, Dimmock N J
Department of Biological Sciences, University of Warwick, Coventry, UK.
J Gen Virol. 1992 Aug;73 ( Pt 8):1995-2001. doi: 10.1099/0022-1317-73-8-1995.
Dugbe virus is a member of the nairovirus genus of the Bunyaviridae. Purified polyclonal anti-Dugbe virus IgG, which neutralized greater than 99.5% of virus, reduced attachment of virus to BSC-1 cell monolayers by only 36%. A 100-fold lower concentration neutralized virus by 88%, and had no effect upon attachment. Neutralizing IgG did not affect the ability of Dugbe virus to be internalized by or to fuse with BSC-1 cells. This suggests that IgG neutralization occurs largely at a stage subsequent to primary uncoating. Purified polyclonal anti-Dugbe virus IgM neutralized infectivity and had no effect on the attachment of virus to cells, but inhibited internalization of virus by about 50%. Thus IgM neutralizes partly by interfering with entry of virus and partly by a post-entry event. Neutralization by intermediate concentrations of IgM was enhanced 20-fold in the presence of complement. At high concentrations of IgM, complement-dependent neutralization declined. This is probably due to IgM binding in a planar rather than crab conformation, which does not expose the complement binding sites. Aggregation occurred only at relatively low concentrations of immunoglobulin. Electron microscopy and reactivation of infectivity by vortexing suggested that aggregation makes only a minor contribution to neutralization by IgG or IgM.
杜格贝病毒是布尼亚病毒科内罗病毒属的成员。纯化的多克隆抗杜格贝病毒IgG可中和超过99.5%的病毒，但仅使病毒与BSC - 1细胞单层的附着减少36%。浓度低100倍的该抗体可中和88%的病毒，且对附着无影响。中和性IgG不影响杜格贝病毒被BSC - 1细胞内化或与之融合的能力。这表明IgG中和作用主要发生在初次脱壳后的阶段。纯化的多克隆抗杜格贝病毒IgM可中和感染性，对病毒与细胞的附着无影响，但可抑制约50%的病毒内化。因此，IgM部分通过干扰病毒进入，部分通过进入后事件发挥中和作用。在补体存在的情况下，中等浓度IgM的中和作用增强了20倍。在高浓度IgM时，补体依赖的中和作用下降。这可能是由于IgM以平面而非蟹状构象结合，从而不暴露补体结合位点。聚集仅在相对低浓度的免疫球蛋白时发生。电子显微镜检查以及通过涡旋使感染性复活表明，聚集对IgG或IgM中和作用的贡献很小。
