ALCOHOL ENHANCES TYPE 1 INTERFERON-α AND MORTALITY OF YOUNG MICE INFECTED WITH Mycobacterium tuberculosis

Abstract In the current study, we determined the effects of chronic alcohol consumption on the mortality of young and old mice and immune responses during Mycobacterium tuberculosis (Mtb) infection. Eighty percent of Mtb H37Rv infected alcohol-fed young mice died in five months compared to twenty-five percent in Mtb infected alcohol-fed old mice. There is no significant difference in lung bacterial burden of control and alcohol diet fed young and old mice. IFN-α levels were significantly higher in the lungs of Mtb infected alcohol-fed young mice and treatment with anti-IFNAR-1 antibody enhanced their survival. There are significantly higher numbers of CD11b+Ly6G+ neutrophils in the lungs of Mtb infected alcoholic young mice compared to Mtb infected alcohol-fed old mice and Mtb infected control diet-fed young mice. CD11b+Ly6G+ neutrophils are the major source of IFN-α in Mtb-infected alcohol-fed young mice and IFN-α enhanced the expression of RIP-1 and RIP-3 molecules, which are known to be involved in necroptosis. Alcohol-fed old Mtb infected mice and Mtb infected control diet-fed old and young mice expressed low level of IFN-α and RIP-1 and RIP-3 in their lungs. In response to Mtb stimulation, peripheral blood mononuclear cells (PBMC) from young healthy alcoholic individuals with latent tuberculosis infection (LTBI) produced significantly higher amounts of IFN-α compared to non-alcoholic young, alcoholic and non-alcoholic old healthy LTBI+ individuals. Our findings demonstrate that in Mtb infected young mice, alcohol enhances CD11b+Ly6G+ neutrophil infiltration in lungs and excess IFN-α production by neutrophils causes lung macrophage necroptosis and enhanced mortality.