Identification of Virulence Determinants within the L Genomic Segment of the Pichinde Arenavirus

• Authors: Lisa McLay, Emory University; Shuiyun Lan, Emory University; Aftab A Ansari, Emory University; Yuying Liang, University of Minnesota; Hinh Ly, University of Minnesota
• Journal Title: Journal of Virology
• Volume: Volume 87, Number 12
• Publisher: American Society for Microbiology | 2013-06-01, Pages 6635-6643
• Type of Work: Article | Final Publisher PDF
• Publisher DOI: http://doi.org/10.1128/JVI.00044-13
• Subjects: Health Sciences, Pathology; Biology, Virology
• Keywords: Science & Technology; Life Sciences & Biomedicine; Virology; LYMPHOCYTIC CHORIOMENINGITIS VIRUS; STRAIN-13 GUINEA-PIGS; RECEPTOR ALPHA-DYSTROGLYCAN; LASSA FEVER; L-PROTEIN; HEMORRHAGIC FEVERS; CELLULAR RECEPTOR; SEQUENCE-ANALYSIS; DENDRITIC CELLS; L-POLYMERASE

Abstract

Several arenaviruses are responsible for causing viral hemorrhagic fevers (VHF) in humans. Lassa virus (LASV), the causative agent of Lassa fever, is a biosafety level 4 (BSL4) pathogen that requires handling in BSL4 facilities. In contrast, the Pichinde arenavirus (PICV) is a BSL2 pathogen that can cause hemorrhagic fever-like symptoms in guinea pigs that resemble those observed in human Lassa fever. Comparative sequence analysis of the avirulent P2 strain of PICV and the virulent P18 strain shows a high degree of sequence homology in the bisegmented genome between the two strains despite the polarized clinical outcomes noted for the infected animals. Using reverse genetics systems that we have recently developed, we have mapped the sequence changes in the large (L) segment of the PICV genome that are responsible for the heightened virulence phenotype of the P18 strain. By monitoring the degree of disease severity and lethality caused by the different mutant viruses, we have identified specific residues located within the viral L polymerase gene encoded on the L segment essential for mediating disease pathogenesis. Through quantitative reverse transcription-PCR (RT-PCR) analysis, we have confirmed that the same set of residues is responsible for the increased viral replicative potential of the P18 strain and its heightened disease severity in vivo. Our laboratory findings serve to reinforce field observations that a high level of viremia often correlates with severe disease outcomes in LASV-infected patients.