Ligation of the BT3 molecules, members of the B7 family, enhance the proinflammatory responses of human monocytes and monocyte-derived dendritic cells

BT3 is a new family of immunoreceptors belonging to the extended B7 family BT3 molecules are expressed on the surface of resting and activated monocytes and monocyte-derived dendritic cells (iDC) We show that BT3 cross-linking in the absence of other survival factors provides a survival signal for monocytes and iDC and induces up-regulation of costimulatory molecules such as CD80 and CD86 and HLA-DR. We further analyzed the effects of BT3 cross-linking on various proinflammatory responses on monocytes and iDC The results obtained showed that BT3 engagement is able to modulate the production of IL8/CXCL8 IL-1 beta and IL-12/p70 Moreover we demonstrated a synergistic effect between BT3 and Toll-like receptors ligands on both monocytes and iDC in up-regulating the production of proinflammatory cytokines Thus BT3 could be involved in the regulation of the balance between Immune activation and suppression A better understanding of its physiological role of these families of receptors awaits the precise identification of the nature origin expression and distribution of their ligands (C) 2010 Published by Elsevier Ltd