Protection of mice from Mycobacterium avium infection by recombinant interleukin-12

Treatment with interleukin-12 (IL-12) significantly reduced the number of viable bacteria in mice infected with Mycobacterium avium. IL-12 itself, however, could not inhibit directly mycobacterial growth in vitro. IL-12 exerts antimycobacterial activity in vivo with a low level of toxicity, possibly by enhancing the host defense against the infection.