A TNF-Regulated Recombinatorial Macrophage Immune Receptor Implicated in Granuloma Formation in Tuberculosis

Abstract

Macrophages play a central role in host defense against mycobacterial infection and anti-TNF therapy is associated with granuloma disorganization and reactivation of tuberculosis in humans. Here, we provide evidence for the presence of a T cell receptor (TCR) alpha beta based recombinatorial immune receptor in subpopulations of human and mouse monocytes and macrophages. In vitro, we find that the macrophage-TCR alpha beta induces the release of CCL2 and modulates phagocytosis. TNF blockade suppresses macrophage-TCR alpha beta expression. Infection of macrophages from healthy individuals with mycobacteria triggers formation of clusters that express restricted TCR V beta repertoires. In vivo, TCR alpha beta bearing macrophages abundantly accumulate at the inner host-pathogen contact zone of caseous granulomas from patients with lung tuberculosis. In chimeric mouse models, deletion of the variable macrophage-TCR alpha beta or TNF is associated with structurally compromised granulomas of pulmonary tuberculosis even in the presence of intact T cells. These results uncover a TNF-regulated recombinatorial immune receptor in monocytes/macrophages and demonstrate its implication in granuloma formation in tuberculosis.