Murine models of M. abscessus infection also display granuloma formation in the lungs and spleen after aerosol or intravenous infection, respectively, and studies using TNF knockout (Tnf−/−) and IFN-γ knockout (Ifngr1−/− and GKO−/−) mice highlight the importance of these cytokines for maintenance of granuloma structure (Rottman et al., 2007; Ordway et al., 2008). Here, TNF is linked to infection.