ROLE OF INTERLEUKIN-12 IN PRIMARY INFLUENZA-VIRUS INFECTION

The effect of endogenous interleukin-12 (IL-12) on the influenza virus immune response in BALB/c mice was evaluated. Following primary influ enza virus infection, IL-12 mRNA and protein are detected in the lung, with live virus being required for cytokine induction. Endogenous IL- 12 contributes to early NK cell-dependent gamma interferon (IFN-gamma) production (days 3 and 5) but not late T-cell-dependent IFN-gamma sec retion (day 7). IL-12 contributes to the inhibition of early virus rep lication but is not required for virus clearance. IL-12 also modestly contributes to the activation of cytotoxic T lymphocytes. Thus, in thi s model of experimental influenza virus infection, endogenous IL-12 co ntributes primarily to the early development and activation of the inn ate immune response.