MMP9 and infection: The increased transcription of Ifnb1 (Figure 4C) and Il1a, Il1b, Cd36, Mmp9 and Mmp12 (data not shown) by 4 hrs post Δ-mce1 H37Rv-infection, in combination with the lack of IL-13 induced immune response support previous findings that, upon an encounter with the Δ-mce1 H37Rv, the macrophage initiates an immunological response which is less able to control bacterial replication leading to more immunopathology than the response induced by the H37Rv wild-type strain.