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甲型流感病毒是病原因子中唯一能发生深刻突变,从而使它能逾越由原来同型病毒感染所建立的特异性免疫的一种病毒。近数年来了解到在病毒的五种或六种结构性多肽中,仅两种与外界环境接触的醣蛋白(红细胞凝集素和神经氨酸酶)能发生明显的抗原性改变。这两种蛋白质抗原的突变是单独发生的。正如人们所意料的,不同的多肽其遗传密码是由不同的基因加以控制。最明显的例子是1968年所出现的流感病毒香港变异株。这种病毒株,其红细胞血凝素与原来流感病毒亚洲甲型(H_2N_2)有
Influenza A is the only virus in the pathogen that undergoes profound mutations that allow it to surpass the specific immunity established by the original homotype. In recent years, it has been learned that only two glycoproteins (hemagglutinin and neuraminidase) which are in contact with the external environment can undergo significant antigenic changes in five or six structural polypeptides of the virus. Mutations in these two protein antigens occur separately. As one might expect, the genetic code of different polypeptides is controlled by different genes. The most obvious example is the 1968 influenza virus Hong Kong mutant. This strain of virus, the hemagglutinin and the original influenza virus Asia A (H_2N_2) have