Abstract
Mycobacterial infections in mice are normally characterized by a profound Th1 cell‐mediated immune response, in which T cells secrete large amounts of IFN‐γ. Recent evidence suggests that this response also includes a Th2 component. In order to investigate whether production of IL‐4, IL‐5, or IL‐10 influenced the outcome of a Mycobacterium bovis‐bacille Calmette‐Guérin (BCG) infection, we intranasally infected IL‐4, IL‐5, and IL‐10 gene‐deficient and control mice and monitored the resulting immune response and bacterial clearance. IL‐4, IL‐5, and IL‐10 deficient mice cleared the mycobacteria with the same kinetics as control mice. Furthermore, T cells of cytokine deficient and control mice produced similar levels of IFN‐γ following in vitro stimulation with purified protein derivative (PPD) from M. bovis. We conclude that the cytokines IL‐4, IL‐5 and IL‐10 are not essential for and do not negatively influence the protective immune response against M. bovis‐BCG in the lung of mice.