Effects of recombinant granulocyte‐colony stimulating factor administration during Mycobacterium avium infection in mice

Granulocyte colony‐stimulating factor (G‐CSF) administration in vivo has been shown to improve the defence mechanisms against infection by different microbes. Here we evaluated a possible protective role of this molecule in a mouse model of mycobacterial infection. The administration of recombinant G‐CSF promoted an extensive blood neutrophilia but failed to improve the course of Mycobacterium avium infection in C57Bl/6 or beige mice. G‐CSF administration also failed to improve the efficacy of a triple chemotherapeutic regimen (clarithromycin + ethambutol + rifabutin). G‐CSF treatment did not protect interleukin‐10 gene disrupted mice infected with M. avium . Spleen cells from infected mice treated with G‐CSF had a decreased priming for antigen‐specific production of interferon gamma compared to control infected mice. Our data do not substantiate previous reports on the protective activity of G‐CSF in antimycobacterial immunity using mouse models.