Virus spread, tissue inflammation and antiviral response in brains of flavivirus susceptible and resistant mice acutely infected with Murray Valley encephalitis virus

• Published in: Archives of virology 2004-03, Vol.149 (3), p.447-464
• Main Authors: SILVIA, O. J, PANTELIC, L, MACKENZIE, J. S, SHELLAM, G. R, PAPADIMITRIOU, J, UROSEVIC, N
• Format: Article
• Language: English
• Subjects: 2',5'-Oligoadenylate Synthetase - genetics; 2',5'-Oligoadenylate Synthetase - metabolism; Acute Disease; Animals; Biological and medical sciences; Brain; Brain - immunology; Brain - physiopathology; Brain - virology; Cytokines; Dengue fever; Encephalitis; Encephalitis Virus, Murray Valley - pathogenicity; Encephalitis Virus, Murray Valley - physiology; Encephalitis, Arbovirus - immunology; Encephalitis, Arbovirus - physiopathology; Encephalitis, Arbovirus - virology; Endoribonucleases - metabolism; Fundamental and applied biological sciences. Psychology; Genes; Human viral diseases; Infections; Infectious diseases; Inflammation; Inflammation - immunology; Inflammation - physiopathology; Interferon Type I - metabolism; Medical sciences; Mice; Mice, Inbred C3H; Microbiology; Miscellaneous; Murray valley encephalitis virus; RNA, Viral - isolation & purification; Viral diseases; Virology; Viruses; West Nile virus
• ISSN: 0304-8608; 1432-8798
• DOI: 10.1007/s00705-003-0238-y

Inborn resistance to flaviviruses, conferred by a single chromosome 5 locus Flv, is a genetic trait operative in wild mice and a few strains of laboratory mice. In this study we have used in situ hybridisation to trace the spread of flavivirus genomic RNA within the brains of flavivirus susceptible C3H/HeJARC and congenic resistant C3H.PRI- Flv(r) mice following infection with Murray Valley encephalitis virus (MVE) in parallel to studying a brain histopathology and induction of cellular genes involved in antiviral response. We find that in contrast to a high viral RNA content in brains of susceptible mice, viral RNA was markedly reduced in the cortex, olfactory bulb, thalamus and hypothalamus of resistant mice. Trace amounts of viral RNA were detected in the medulla oblongata while it was completely absent from the hippocampus, pons and cerebellum of resistant mice at different time points post infection. The low virus titres within brains of resistant mice coincided with a very mild inflammation, low counts of infiltrating inflammatory cells, and lower IFN I/II and TNFalpha gene induction than in susceptible mice. Furthermore, transcripts of several genes belonging to a 2',5'-oligoadenylate synthetase ( OAS) family, implicated in IFN I-inducible OAS/RNase L antiviral pathway, showed similar brain tissue induction in both strains of mice suggesting only minor contribution of this pathway to the resistance phenotype.