| First Author | Yamamoto N | Year | 2004 |
| Journal | Microbes Infect | Volume | 6 |
| Issue | 14 | Pages | 1241-9 |
| PubMed ID | 15555529 | Mgi Jnum | J:105589 |
| Mgi Id | MGI:3615880 | Doi | 10.1016/j.micinf.2004.08.007 |
| Citation | Yamamoto N, et al. (2004) Essential role for the p40 subunit of interleukin-12 in neutrophil-mediated early host defense against pulmonary infection with Streptococcus pneumoniae: involvement of interferon-gamma. Microbes Infect 6(14):1241-9 |
| abstractText | Interleukin (IL)-12 is a critical cytokine in the T helper (Th)1 response and host defense against intracellular microorganisms, while its role in host resistance to extracellular bacteria remains elusive. In the present study, we elucidated the role of IL-12 in the early-phase host defense against acute pulmonary infection with Streptococcus pneumoniae, a typical extracellular bacterium, using IL-12p40 gene-disrupted (IL-12p40KO) mice. IL-12p40KO mice were highly susceptible to S. pneumoniae infection, as indicated by the shortened survival time, which was completely restored by the replacement therapy with recombinant (r) IL-12, and increased bacterial counts in the lung. In these mice, recruitment of neutrophils in the lung was significantly attenuated when compared to that in wild-type (WT) mice, which correlated well with the reduced production of macrophage inflammatory protein (MIP-2) and tumor necrosis factor (TNF)-alpha in the infected tissues at the early phase of infection. In vitro synthesis of both cytokines by S. pneumoniae-stimulated lung leukocytes was significantly lower in IL-12p40KO mice than in WT mice, and addition of rIL-12 or interferon (IFN)-gamma restored the reduced production of MIP-2 and TNF-alpha in IL-12p40KO mice. Neutralizing anti-IFN-gamma monoclonal antibody (mAb) significantly decreased the effect of rIL-12. Anti-IFN-gamma mAb shortened the survival time of infected mice and reduced the recruitment of neutrophils and production of MIP-2 and TNF-alpha in the lungs. Our results indicated that IL-12p40 plays a critical role in the early-phase host defense against S. pneumoniae infection by promoting the recruitment of neutrophils to the infected tissues. |
