PROTEOLYTIC CLEAVAGE OF HEMAGGLUTININ POLYPEPTIDE OF INFLUENZA-VIRUS - FUNCTION OF UNCLEAVED POLYPEPTIDE HA
PROTEOLYTIC CLEAVAGE OF HEMAGGLUTININ POLYPEPTIDE OF INFLUENZA-VIRUS - FUNCTION OF UNCLEAVED POLYPEPTIDE HA
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DOI：
10.1016/0042-6822(73)90409-1
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发表时间：
1973-01-01
期刊：
影响因子：
3.7
通讯作者：
CHOPPIN, PW
中科院分区：
文献类型：
--
作者：
LAZAROWI.SG;COMPANS, RW;CHOPPIN, PW
使用在不同宿主细胞中生长的A0型流感WSN毒株和A2型流感RI/5-毒株，研究了HA多肽（流感病毒最大的糖蛋白）裂解为多肽HA1和HA2。感染性血凝病毒颗粒的组装不需要 HA 多肽的裂解。裂解既依赖于菌株又依赖于宿主细胞，并且与细胞损伤的程度相关，这表明所涉及的酶是宿主细胞特异的。在培养基中不含小牛血清的 MDBK 细胞中生长的病毒颗粒几乎完全含有未切割的 HA 多肽。当细胞病变效应广泛时，在生长周期早期收获的病毒粒子比从相同细胞后期收获的病毒粒子含有更多未切割的HA多肽。裂解的蛋白水解性质已在体外用胰蛋白酶证实。对含有不同量的未切割的HA多肽和切割产物HA1和HA2的病毒体的特异性血凝活性和感染性以及这些病毒体与可溶性糖蛋白受体物质胎球蛋白反应的能力的比较表明，未切割的HA多肽在血凝和吸附细胞和可溶性受体方面与由HA1和HA2组成的二硫键复合物具有同样的活性。因此，病毒组装或病毒体生物学特性的完全表达不需要HA多肽蛋白水解为HA1和HA2。相反，它似乎是正在经历细胞病变效应的受感染细胞中发生的事件的非本质结果。
The cleavage of the HA polypeptide, the largest glycoprotein of influenza virus, to polypeptides HA1 and HA2 has been studied using the WSN strain of influenza A0and the RI/5−strain of influenza A2grown in different host cells. Cleavage of the HA polypeptide is not required for the assembly of infectious, hemagglutinating virions. Cleavage is both strain dependent and host cell dependent, and correlates with the extent of cell damage, suggesting that the enzymes involved are host cell specified. Virions grown in MDBK cells without calf serum in the medium contain almost entirely uncleaved HA polypeptides. Virions harvested early in the growth cycle contain more uncleaved HA polypeptide than virions harvested late from the same cells when cytopathic effects are extensive. The proteolytic nature of the cleavage has been demonstratedin vitrowith trypsin. Comparison of the specific hemagglutinating activity and infectivity of virions which contain different amounts of the uncleaved HA polypeptide and the cleavage products HA1 and HA2, and of the capacity of such virions to react with the soluble glycoprotein receptor substance fetuin, have shown that uncleaved HA polypeptides are as active in hemagglutination and adsorption to cellular and soluble receptors as are the disulfide-bonded complexes composed of HA1 plus HA2. The proteolytic cleavage of the HA polypeptide to HA1 and HA2 is thus not required for virus assembly or for full expression of the biological properties of the virion. Rather, it appears to be a nonessential result of events occurring in infected cells which are undergoing cytopathic effects.