UNSPECIFIED. (1993) PROTECTION OF 3 STRAINS OF MICE AGAINST LETHAL INFLUENZA IN-VIVO BY DEFECTIVE INTERFERING VIRUS. VIRUS RESEARCH, 29 (2). pp. 179-193. ISSN 0168-1702

Abstract

This report examines the protective effects of defective interfering (DI) WSN on three strains of mice (C3H/He-mg (H-2k), C57BL/6 (H-2b) and BALB/c (H-2d)) infected with various doses of A/WSN influenza virus. All three strains were protected in terms of morbidity and mortality, to varying extents. DI WSN protected optimally against a low but lethal dose of A/WSN in C3H/He-mg mice, but also protected this and other strains against very high doses of A/WSN. Intermediate sized inocula gave little, if any, protection. In all cases protection required an active DI genome since inactivation with beta-propiolactone abrogated any sparing effect. Consolidation of the lungs was reduced by treatment with active DI virus, but at some doses of inoculum there was reduction in lung pathology without reduction of mortality. Treatment of infected mice with DI virus did not reduce the lung virus titre, but in C3H/He-mg mice resulted in recovery of infectious virus from other tissues, notably the heart, where it was not normally found. No infectivity was recovered from brain, liver or serum. Haemagglutination-inhibiting (HI) antibody could not be detected in the lungs of any of the infected mice co-inoculated with the control BPL-inactivated DI WSN but was present in considerable amounts in all three strains when these were co-inoculated with DI virus. These and previous data (Morgan and Dimmock, 1992) suggested that influenza virus was immunosuppressive and that active DI virus abrogated these suppressive effects. However, these effects are selective as we found that lung NK cell activity was not suppressed during lethal infection and was unaffected when mice were coinoculated with DI virus. The UV target size of the DI virus genome which protected C3H/He-mg mice and interfered with viral c.p.e. in MDCK cells was found to be 350 and 407 nucleotides respectively.

Data sourced from Thomson Reuters' Web of Knowledge

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