Identification of Adult Mouse Neurovirulence Determinants of the Sindbis Virus Strain AR86

Abstract

Sindbis virus infection of mice has provided valuable insight into viral and host factors that contribute to virus-induced neurologic disease. In an effort to further define the viral genetic elements that contribute to adult mouse neurovirulence, the neurovirulent Sindbis virus strain AR86 was compared to the closely related (22 single amino acid coding changes and the presence or absence of an 18-amino-acid sequence in nsP3 [positions 386 to 403]) but avirulent Girdwood strain. Initial studies using chimeric viruses demonstrated that genetic elements within the nonstructural and structural coding regions contributed to AR86 neurovirulence. Detailed mapping studies identified three major determinants in the nonstructural region, at nsP1 538 (Ile to Thr; avirulent to virulent), an 18-amino-acid deletion in nsP3 (positions 386 to 403), and nsP3 537 (opal to Cys; avirulent to virulent), as well as a single determinant in the structural genes at E2 243 (Leu to Ser; avirulent to virulent), which were essential for AR86 adult mouse neurovirulence. Replacing these codons in AR86 with those found in Girdwood resulted in the attenuation of AR86, while the four corresponding AR86 changes in the Girdwood genetic background increased virulence to the level of wild-type AR86. The attenuating mutations did not adversely affect viral replication in vitro, and the attenuated viruses established infection in the brain and spinal cord as efficiently as the virulent viruses. However, the virus containing the four virulence determinants grew to higher levels in the spinal cord at late times postinfection, suggesting that the virus containing the four attenuating determinants either failed to spread or was cleared more efficiently than the wild-type virus.

Characterization of Ross River Virus Tropism and Virus-Induced Inflammation in a Mouse Model of Viral Arthritis and Myositis

“…However, studies of adult mice have demonstrated that infection with most Sindbis group alphaviruses results in encephalitic disease (11,37). Recent work has demonstrated that Sindbis group alphaviruses, such as S.A.AR86 and TR339, replicated in bone and joint-associated tissues of adult CD-1 mice; however, virus-induced inflammation or other pathology was not observed within these tissues (15).…”

An alphavirus replicon-derived candidate vaccine against Rift Valley fever virus

“…For the Girdwood replicon system, the non-structural coding region of the genome from nucleotides 41-6463 was transferred from the full-length infectious clone pG100 [23] into the AR86-based replicon pREP89 [22], using restriction enzymes MfeI and BstBI. All non-structural coding differences between AR86 and GirdwoodS.A.…”

A Determinant of Sindbis Virus Neurovirulence Enables Efficient Disruption of Jak/STAT Signaling

“…(called Girdwood hereafter). In adult mice, a virus derived from the infectious clone of AR86 (S300) causes lethal disease following intracranial inoculation (27,28,58,60), while the closely related Girdwood virus (clone G100) is avirulent, even though both S300 and G100 replicate to similar levels within the CNS of mice at early times postinfection (60). The difference in virulence is mediated by four genetic determinants within AR86, which result in a gain of full virulence when introduced into the avirulent G100 background.…”