National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA.
J Virol. 2012 Jan;86(1):420-6. doi: 10.1128/JVI.02327-10. Epub 2011 Oct 19.
La Crosse virus (LACV) and Jamestown Canyon virus (JCV), family Bunyaviridae, are mosquito-borne viruses that are endemic in North America and recognized as etiologic agents of encephalitis in humans. Both viruses belong to the California encephalitis virus serogroup, which causes 70 to 100 cases of encephalitis a year. As a first step in creating live attenuated viral vaccine candidates for this serogroup, we have generated a recombinant LACV expressing the attachment/fusion glycoproteins of JCV. The JCV/LACV chimeric virus contains full-length S and L segments derived from LACV. For the M segment, the open reading frame (ORF) of LACV is replaced with that derived from JCV and is flanked by the untranslated regions of LACV. The resulting chimeric virus retained the same robust growth kinetics in tissue culture as observed for either parent virus, and the virus remains highly infectious and immunogenic in mice. Although both LACV and JCV are highly neurovirulent in 21 day-old mice, with 50% lethal dose (LD₅₀) values of 0.1 and 0.5 log₁₀ PFU, respectively, chimeric JCV/LACV is highly attenuated and does not cause disease even after intracerebral inoculation of 10³ PFU. Parenteral vaccination of mice with 10¹ or 10³ PFU of JCV/LACV protected against lethal challenge with LACV, JCV, and Tahyna virus (TAHV). The chimeric virus was infectious and immunogenic in rhesus monkeys and induced neutralizing antibodies to JCV, LACV, and TAHV. When vaccinated monkeys were challenged with JCV, they were protected against the development of viremia. Generation of highly attenuated yet immunogenic chimeric bunyaviruses could be an efficient general method for development of vaccines effective against these pathogenic viruses.
拉科罗拉多病毒（LACV）和詹姆士敦峡谷病毒（JCV），均属于布尼亚病毒科，是北美的地方性蚊媒病毒，被认为是人类脑炎的病原体。这两种病毒都属于加利福尼亚脑炎病毒血清群，每年导致 70 至 100 例脑炎。作为为该血清群开发活减毒病毒候选疫苗的第一步，我们生成了一种表达 JCV 附着/融合糖蛋白的重组 LACV。JCV/LACV 嵌合病毒包含源自 LACV 的全长 S 和 L 片段。对于 M 片段，LACV 的开放阅读框（ORF）被来自 JCV 的 ORF 替换，并且被 LACV 的非翻译区侧翼。所得嵌合病毒在组织培养中保持与亲本病毒相同的强大生长动力学，并且在小鼠中仍然高度感染和免疫原性。尽管 LACV 和 JCV 在 21 天大的小鼠中均具有高度神经毒力，半数致死量（LD₅₀）值分别为 0.1 和 0.5 log₁₀ PFU，但嵌合 JCV/LACV 高度减毒，即使脑内接种 10³ PFU 也不会引起疾病。用 10¹或 10³ PFU 的 JCV/LACV 对小鼠进行肠道外接种可预防致死性 LACV、JCV 和 Tahyna 病毒（TAHV）挑战。嵌合病毒在恒河猴中具有感染性和免疫原性，并诱导针对 JCV、LACV 和 TAHV 的中和抗体。当接种疫苗的猴子受到 JCV 挑战时，它们可以防止病毒血症的发展。生成高度减毒但具有免疫原性的嵌合 bunyavirus 可能是开发针对这些致病性病毒有效的疫苗的有效通用方法。
