Bold S, Ohlin M, Garten W, Radsak K
Institut für Virologie der Philipps-Universität, Marburg, Germany.
J Gen Virol. 1996 Sep;77 ( Pt 9):2297-302. doi: 10.1099/0022-1317-77-9-2297.
A novel fusion assay was established to determine fusion activity with cocultivated human foreskin fibroblasts of stable transfectants derived from human astrocytoma cells (U373) expressing authentic or mutagenized human cytomegalovirus glycoprotein B (HCMV gB; gpUL55). Compared to transfectants expressing authentic HCMV gB, those expressing gB forms with a deletion of hydrophobic domain 1 (hd1; aa 714-747) or with deletions of specific segments in the cytoplasmic tail (aa 811-825 and 871-906) exhibited significantly reduced heterologous fusogenicity. HCMV gB-specific monoclonal antibodies (MAbs) as well as MAb against cellular annexin II prevented fusion of the transfectant expressing authentic gB. Comparable surface exposure of HCMV gB or its derivatives was demonstrated in all transfectants by FACS analysis. Our observations are compatible with the notion that indigenous fusion activity of HCMV gB depends on the extracellular hd1 domain and on the conformation of the cytoplasmic tail.
建立了一种新型融合测定法，以确定源自表达天然或诱变人巨细胞病毒糖蛋白B（HCMV gB；gpUL55）的人星形细胞瘤细胞（U373）的稳定转染子与共培养的人包皮成纤维细胞的融合活性。与表达天然HCMV gB的转染子相比，那些表达缺失疏水结构域1（hd1；氨基酸714 - 747）或细胞质尾巴特定片段缺失（氨基酸811 - 825和871 - 906）的gB形式的转染子表现出显著降低的异源融合性。HCMV gB特异性单克隆抗体（MAb）以及针对细胞膜联蛋白II的MAb可阻止表达天然gB的转染子的融合。通过流式细胞术分析在所有转染子中证实了HCMV gB或其衍生物具有相当的表面暴露。我们的观察结果与以下观点一致，即HCMV gB的固有融合活性取决于细胞外hd1结构域和细胞质尾巴的构象。
