Olsen C W, McGregor M W, Cooley A J, Schantz B, Hotze B, Hinshaw V S
Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin, Madison 53706.
Am J Vet Res. 1993 Oct;54(10):1630-6.
Hemagglutinins (HA) of H1N1 swine influenza viruses isolated in the United States have remained antigenically and genetically conserved for many years. In contrast to such conservation, the HA of A/Swine/Nebraska/1/92 (Sw/Neb) could readily be distinguished from those of contemporary porcine viruses. Twenty-eight amino acid mutations differentiated the HA of Sw/Neb and A/Swine/Indiana/1726/88, the most recent H1N1 swine influenza virus for which HA sequence data were available. Among these differences were mutations at potential asparagine-linked glycosylation sites and charge changes at many residues. The Sw/Neb virus also could be differentiated from other swine influenza viruses in hemagglutination-inhibition assays with monoclonal antibodies to recent H1 swine HA. Nonetheless, overall sequence analysis of the HA and the nucleoprotein genes of Sw/Neb indicated that this virus was more closely related genetically to classic H1N1 swine influenza viruses than to H1N1 avian or human viruses. Infection of swine with Sw/Neb under experimental conditions induced clinical signs and lesions typical of swine influenza. However, affected swine in the field had high, persistent fevers, but relatively mild signs of respiratory tract disease. This study indicated that an antigenically and genetically novel variant of swine influenza virus was detected in the United States.
在美国分离出的H1N1猪流感病毒的血凝素（HA）多年来在抗原性和基因上一直保持保守。与这种保守情况形成对比的是，A/猪/内布拉斯加州/1/92（Sw/Neb）的HA很容易与当代猪病毒的HA区分开来。28个氨基酸突变使Sw/Neb的HA与A/猪/印第安纳州/1726/88的HA有所不同，A/猪/印第安纳州/1726/88是有HA序列数据的最新H1N1猪流感病毒。这些差异包括潜在的天冬酰胺连接糖基化位点的突变以及许多残基处的电荷变化。在针对近期H1猪HA的单克隆抗体的血凝抑制试验中，Sw/Neb病毒也能与其他猪流感病毒区分开来。尽管如此，对Sw/Neb的HA和核蛋白基因的整体序列分析表明，该病毒在基因上与经典H1N1猪流感病毒的关系比与H1N1禽流感或人流感病毒的关系更密切。在实验条件下用Sw/Neb感染猪会引发猪流感典型的临床症状和病变。然而，现场受感染的猪出现持续高烧，但呼吸道疾病症状相对较轻。这项研究表明，在美国检测到了一种抗原性和基因上全新的猪流感病毒变体。
