Activation of tuberculostatic macrophage functions by gamma interferon, interleukin-4, and tumor necrosis factor

Abstract

The capacity of the cytokines gamma interferon (IFN-γ), interleukin-4 (IL-4), and tumor necrosis factor (TNF) to activate tuberculostatic functions in murine bone marrow-derived macrophages (BMMΦ) was investigated. In confirmation of earlier findings, IFN-γ rendered BMMΦ capable of inhibiting subsequent infection with Mycobacterium bovis. In contrast, IL-4 and TNF failed to inhibit mycobacterial growth. However, in already infected BMMΦ, tuberculostasis was induced by subsequent stimulation with IL-4. Although TNF alone was ineffective, it showed synergy with IFN-γ in the stimulation of tuberculostasis. Our data suggest that not only IFN-γ but also IL-4 and TNF participate in the control of mycobacterial growth.