Emerging themes in IFN-gamma-induced macrophage immunity by the p47 and p65 GTPase families.

Vertebrates have evolved complex immune specificity repertoires beyond the primordial components found in lower multi-cellular organisms to combat microbial infections. The type II interferon (IFN-gamma) pathway represents one such system, bridging innate and acquired immunity and providing host protection in a cell-autonomous manner. Recent large-scale transcriptome analyses of IFN-gamma-dependent gene expression in effector cells such as macrophages have highlighted the prominence of two families of GTPases -- p47 IRGs and p65 GBPs -- that are now beginning to emerge as major determinants of antimicrobial resistance. Here we discuss the recent clarification of known family members, their cellular biochemistry and host defense functions as a means to understanding the complex innate immune response engendered in higher vertebrates such as humans and mice.