Differing responses of hamsters to infection by vesicular stomatitis virus Indiana and New Jersey serotypes

Abstract

Intraperitoneal injection of vesicular stomatitis virus, New Jersey serotype (VSV-NJ), into inbred LSH hamsters resulted in an inapparent infection and survival of the majority of the animals. Infectivity titrations of tissues from VSV-NJ-infected hamsters showed that little or no virus was present following infection. The few animals that died from VSV-NJ succumbed to neurological disease. This is in contrast to our previous work where we found that LSH hamsters are exquisitely sensitive to i.p. infection by VSV, Indiana serotype (VSV-IND), and that large amounts of VSV-IND could be detected in tissues. The 50% lethal doses of VSV-NJ and VSV-IND for LSH hamsters are approximately 10⁷ pfu and 1 pfu, respectively. When peritoneal cells from LSH hamsters were infected in vitro with both VSV serotypes, the yields of VSV-NJ consistently were lower than yields of VSV-IND. The growth of the two serotypes in fibroblast and epithelial cell lines of hamster origin was similar. VSV-NJ was not more efficient than VSV-IND in inducing interferon in vitro or in vivo, and there appeared to be no difference in the sensitivities of the two serotypes to the antiviral activity of hamster interferon. Thus, i.p. infection with less than 10⁷ pfu of VSV-NJ is avirulent for LSH hamsters and this avirulence may be due, in part, to partial.intrinsic resistance of peritoneal macrophages to infection by VSV-NJ. When four LSH hamsters that had been immunized with VSV-NJ were challenged with 10⁶ LD₅₀ of VSV-IND, three of the four animals survived. Despite the fact that neutralizing antibodies to VSV-NJ did not cross-neutralize VSV-IND, five out of five LSH hamsters were protected by passive transfer of 1 ml of immune hamster anti-VSV-NJ antiserum prior to challenge with VSV-IND. This suggests an important role for non-neutralizing antibodies.