BT3 molecules ligation enhances the proinflammatory responses of human monocytes and monocyte-derived dendritic cells

BT3, a new family of immunoreceptors, belongs to the extended B7 family. BT3 are expressed on the surface of resting and activated monocytes and monocytes-derived dendritic cells (iDC). We show that BT3 cross-linking, in the absence of other survival factors, provides a survival signal for monocytes. We further analysed the effects of BT3 cross-linking on various proinflammatory responses. Results obtained showed that BT3 engagements is able to modulate production of IL8/CXCL8, IL-I b and IL-I 2/p70. Moreover, we demostrated a co-stimulatory effect of BT3 receptors.