VISTA as a ligand downregulates LPS-mediated inflammation in macrophages and neutrophils
V-domain immunoglobulin suppressor of T-cell activation (VISTA) has emerged as a unique immunoregulatory receptor on cells of the myeloid lineage. Agonizing VISTA on myeloid cells has recently been demonstrated to have a profound effect on dampening inflammatory responses. VISTA has been proposed to function both as a ligand and as a receptor. In this context, the role of VISTA as a ligand has been largely ignored. Using a high-avidity agonist of the VISTA receptor (VISTA-COMP), we investigated the effect of exogenous VISTA, as a ligand, on macrophages and neutrophil cellular pathways in an acute inflammatory setting. RNA sequencing analysis demonstrated that VISTA-COMP downregulates pro-inflammatory cytokines and chemokines and upregulates immunoregulatory genes in both LPS-stimulated macrophages and neutrophils ex vivo. Interestingly, unlike VISTA itself, the receptor is only expressed following LPS stimulation of these cell populations. Furthermore, the administration of VISTA-COMP attenuated the rise in circulating TNF levels in LPS-treated mice in vivo. These results suggest that VISTA serves a redundant role on macrophages and neutrophils acting as both a ligand and a receptor in the context of an acute inflammatory event.