Adenoviral-Mediated Interferon-γ Gene Therapy Augments Pulmonary Host Defense of Ethanol-Treated Rats.

Alcohol has long been recognized as an immunosuppressive drug and a risk factor for a spectrum of infectious diseases. Among these infections, bacterial pneumonias are most closely correlated with alcohol abuse. One potential mechanism of ethanol-induced immunosuppression is through its ability to suppress alveolar macrophage production of tumor necrosis factor (TNF-α). This defect can be reversed by priming macrophages with interferon-γ (IFN-γ). We hypothesized that macrophage priming in vivo in a model of acute ethanol intoxication could augment pulmonary host defenses. To test this hypothesis, we used adenoviral-mediated gene transfer of the IFN-γ gene. This strategy resulted in prolonged expression of IFN-γ in vivo. Moreover, in a model of acute ethanol intoxication, this vector significantly enhanced lipopolysaccharide-induced TNF-α responses and lung polymorphonuclear leukocyte recruitment. Furthermore, pulmonary host defenses against Klebsiella pneumoniae were were significantly augmented. These enhanced host defenses were not reversed with pretreatment with a polyclonal anti-TNF-α antibody, suggesting that IFN-γ's effect was through a non-TNF-α-dependent mechanism. These data demonstrate that ethanol-induced suppression of pulmonary host defenses can be reversed with IFN-γ gene therapy. [ABSTRACT FROM AUTHOR]