Altered Neurovirulence of Temperature-sensitive Vesicular Stomatitis Virus Mutants in a Murine Model by Inoculation of Bombesin: a Neuropeptide. I. Clinical, Virological and Pathological Observations

Previous work in our laboratory has demonstrated that only certain temperature-sensitive (ts) mutants of vesicular stomatitis virus (VSV) appear capable of producing central nervous system (CNS) infection in a mouse model system. Considerable effort has been devoted to studies directed at unraveling the mechanisms underlying host virulence with these tsVSV mutants. With the previous demonstration that certain neuropeptides, capable of lowering body temperature, alter avirulent into virulent infection, we explored the role of one of these neuropeptides, bombesin, in CNS infection induced by normally avirulent tsG11 VSV, as well as certain tsVSV mutants derived from persistently infected (pi) carrier cultures. Our observations indicate that bombesin dramatically alters CNS infection with either tsG11 VSV as well as tsVSV mutants derived from persistent carrier cultures. When virus alone was inoculated intracerebrally, no sign of illness was observed and no animal died. When bombesin was injected along with normally avirulent tsG11 VSV, or glioma derived tsG31 VSV, 50% of mice died within 6-8 days after inoculation. Moreover, mice infected with virus and neuropeptide demonstrated striking pathological alterations in the CNS. These studies are in agreement with previously published results from others as well as our own laboratory and strongly suggest a direct correlation between CNS temperature and the capacity of certain tsVSV mutants to induce clinical and pathological disease.