Improvement of the resistance against early Mycobacterium tuberculosis-infection in the absence of PI3K gamma enzyme is associated with increase of CD4+IL-17+cells and neutrophils

Given the impossibility to study the lung immune response during Mycobacterium tuberculosis-latent infection, and consequently, the mechanisms that control the bacterial load, it is reasonable to determine the activation of local immunity in the early phase of the infection. The phosphatidylinositol-3-kinase gamma enzyme (PI3K gamma) is involved in the leukocyte recruitment, phagocytosis and cellular differentiation, and therefore, it is considered a promising target for the development of immunotherapies for chronic inflammatory diseases. Mice genetically deficient in PI3K gamma (PI3K gamma(-/-)) or WT (Wild Type) were evaluated 15 days post-infection. The enzyme deficiency improved the resistance against infection, increased the frequency of CD4(+)IL-17(+) cells, the production of IL-17 as well as the gene and protein expression of molecules associated with Th17 cell differentiation and neutrophil recruitment. Our findings show, for the first time, the participation of the PI3K gamma in vivo in the M. tuberculosis-infection, and suggest an association of Th17 cells with protection in the early phase of tuberculosis. (AU)