Effect of Interferon-γ Treatment on the Course of a Burn Wound Infection

Interferon-γ (IFN-γ) has been shown to have immunoregulatory properties and is able to modulate resistance to several microbial infections. This study was designed to determine the efficacy of IFN-γ treatment in a murine burn wound infection model. Bacterial challenge consisted of Klebsiella pneumoniae (10⁸ organisms/ml) or Pseudomonas aeruginosa (10^s organisms/ml), applied topically immediately after burning. Groups of CBA/J mice received either IFN-γ or RPMI-1640 medium (controls) subcutaneously. IFN-γ was administered daily at a dose of 7,500 units for 5 days prior to bacterial challenge. Burn without bacterial challenge produced no mortality. Mice treated with IFN-γ survived significantly longer than controls when the bacterial challenge was K. pneumoniae. There was no difference in survival when bacterial challenge was P. aeruginosa. The la antigen expression of peripheral blood mononuclear cells was severely reduced for 3 days post-burn. This drop was prevented on day 3 post-burn in mice treated with IFN-γ. These data indicate that interferon was effective treatment in a murine model of Klebsiella burn wound infection and was associated with maintenance of la antigen expression that may have contributed to the action of the IFN-γ.