CD84 (Cluster of Differentiation 84) is a human protein encoded by the CD84 gene.

This gene encodes a membrane glycoprotein that is a member of the signaling lymphocyte activation molecule (SLAM) family. This family forms a subset of the larger CD2 cell-surface receptor Ig superfamily. The encoded protein is a homophilic adhesion molecule that is expressed in numerous immune cells types and is involved in regulating receptor-mediated signaling in those cells. Alternate splicing results in multiple transcript variants. [provided by RefSeq, Oct 2011].
Function: Plays a role as adhesion receptor functioning by homophilic interactions and by clustering. Recruits SH2 domain-containing proteins SH2D1A/SAP. Increases proliferative responses of activated T-cells and SH2D1A/SAP does not seen be required for this process. Homophilic interactions enhance interferon gamma/IFNG secretion in lymphocytes and induce platelet stimulation via a SH2D1A/SAP-dependent pathway. May serve as a marker for hematopoietic progenitor cells.