In mycobacterial infections of mice there is a chronic, immune-mediated mobilization of neutrophils to the infectious site. In this study we evaluated the role played by cytokines in the chronic peritoneal neutrophilia which occurs in mice intraperitoneally infected with Mycobacterium bovis BCG or M. avium. Antibodies to IFN-gamma and to MIP-1 and -2 were effective in reducing peritoneal neutrophilia when given during the infection. Whereas the former antibody was only effective when given early, the latter two were effective when administered late in infection, suggesting the MIPs were direct mediators of neutrophil recruitment. Recombinant IFN-gamma given intraperitoneally induced the accumulation of neutrophils and primed the peritoneal cells for an enhanced recruitment of neutrophils. Our data show that chronic neutrophilia during mycobacterial infection is regulated by different cytokines acting at different stages and levels of neutrophil recruitment.