The role of IL-4 and IL-13 in pulmonary tuberculosis using gene-deficient mice and protective efficacy of the purine-deficient auxotroph of Mycobacterium tuberculosis

Abstract

Absence of the TH2 inducing cytokine IL-4 has been shown not to increase the TH1 response and resistance to mycobacterial infection. This study asked whether the combined absence of IL-4 and IL3, as compared to IL-4 deficiency only, would increase resistance to an aerogenic Mycobacterium tuberculosis infection. By using IL-4 gene-deficient mice, it was confirmed that endogenous IL-4 does not reduce host immunity. In contrast, IL-4Rα genedeficient mice, which lack both IL-4 and IL-13 signalling, had reduced bacterial burden in the lungs and other organs, increased survival and cellular immunity with macrophage activation. Therefore IL-4Rα gene-deficient mice have increased resistance to Mycobacterium tuberculosis infection.