Antibody and Interleukin-12 Treatment in Murine Models of Encephalitogenic Flavivirus (St. Louis Encephalitis, Tick-Borne Encephalitis) and Alphavirus (Venezuelan Equine Encephalitis) Infection

Early and sustained treatment with interleukin-12 (IL-12) ameliorated disease in a mouse model of infection with the encephalitogenic flavivirus, St. Louis encephalitis virus (SLEV, Japanese encephalitis serogroup). However, this effect was not reproduced in murine infections with either the flavivirus tick-bore encephalitis virus (TBEV) or the alphavirus Venezuelan equine encephalitis virus (VEEV). IL-12 exacerbated TBEV disease when used in conjunction with monoclonal antibody (mAb), suggesting an enhancement of immunopathology, and was without clinical effects in VEEV infection. These data confirm the need to fully understand the pathogenesis of viral infection before cytokine intervention may be employed as a broad-spectrum antiviral therapy.