Barbosa A T, Luiz M O, Gusmão N P, Couceiro J N
Departamento de Virologia, Instituto de Microbiologia Prof. Paulo de Góes, Universidade Federal do Rio de Janeiro, Brasil.
Braz J Med Biol Res. 1997 Dec;30(12):1415-20. doi: 10.1590/s0100-879x1997001200005.
In the present investigation we studied the fusogenic process developed by influenza A, B and C viruses on cell surfaces and different factors associated with virus and cell membrane structures. The biological activity of purified virus strains was evaluated in hemagglutination, sialidase and fusion assays. Hemolysis by influenza A, B and C viruses ranging from 77.4 to 97.2%, from 20.0 to 65.0% from 0.2 to 93.7% and from 9.0 to 76.1% was observed when human, chicken, rabbit and monkey erythrocytes, respectively, were tested at pH 5.5. At this pH, low hemolysis indexes for influenza A, B and C viruses were observed if horse erythrocytes were used as target cells for the fusion process, which could be explained by an inefficient receptor binding activity of influenza on N-glycolyl sialic acids. Differences in hemagglutinin receptor binding activity due to its specificity to N-acetyl or N-glycolyl cell surface oligosaccharides, density of these cellular receptors and level of negative charges on the cell surface may possibly explain these results, showing influence on the sialidase activity and the fusogenic process. Comparative analysis showed a lack of dependence between the sialidase and fusion activities developed by influenza B viruses. Influenza A viruses at low sialidase titers (< 2) also exhibited clearly low hemolysis at pH 5.5 (15.8%), while influenza B viruses with similarly low sialidase titers showed highly variable hemolysis indexes (0.2 to 78.0%). These results support the idea that different virus and cell-associated factors such as those presented above have a significant effect on the multifactorial fusion process.
在本研究中，我们研究了甲型、乙型和丙型流感病毒在细胞表面引发的融合过程以及与病毒和细胞膜结构相关的不同因素。通过血凝、唾液酸酶和融合试验评估了纯化病毒株的生物活性。在pH 5.5条件下，分别用人、鸡、兔和猴的红细胞进行测试时，甲型、乙型和丙型流感病毒引起的溶血率分别为77.4%至97.2%、20.0%至65.0%、0.2%至93.7%和9.0%至76.1%。在此pH值下，如果将马红细胞用作融合过程的靶细胞，则观察到甲型、乙型和丙型流感病毒的溶血指数较低，这可能是由于流感病毒对N-羟乙酰神经氨酸的受体结合活性效率低下所致。血凝素受体结合活性因其对N-乙酰或N-羟乙酰细胞表面寡糖的特异性、这些细胞受体的密度以及细胞表面负电荷水平的差异，可能解释了这些结果，表明其对唾液酸酶活性和融合过程有影响。比较分析表明，乙型流感病毒的唾液酸酶活性和融合活性之间缺乏相关性。甲型流感病毒在低唾液酸酶滴度（<2）时，在pH 5.5条件下也表现出明显较低的溶血率（15.8%），而唾液酸酶滴度相似的乙型流感病毒则表现出高度可变的溶血指数（0.2%至78.0%）。这些结果支持了这样一种观点，即上述不同的病毒和细胞相关因素对多因素融合过程有显著影响。
