The 1D3/CD84 monoclonal antibody specifically recognizes CD84 which is also known as Signaling lymphocytic activation molecule 5 (SLAM family member 5 or Slamf5). CD84 is a single-pass type I transmembrane glycoprotein that is encoded by Cd84 (CD84 antigen) which belongs to the SLAM family within the CD2-subset of the immunoglobulin superfamily (IgSF) of cell surface receptors. CD84 is comprised of an extracellular region with one N-terminal Ig-like V-type (IgV) domain followed by one Ig-like C2-type (IgC2) domain. Its cytoplasmic tail contains two immunoreceptor tyrosine-based switch motifs (ITSMs) and serves as a docking site for activating adaptor molecules, SLAM-associated protein (SAP) or EWS-activated transcript 2 (EAT-2), or inhibitory SH2-binding phosphatases. CD84 is variably expressed on B cells, T cells, NK cells, monocytes, macrophages, dendritic cells, granulocytes, mast cells, hematopoietic progenitor cells, and platelets. CD84 is a homotypic adhesion molecule that can function as a coreceptor in the regulation of innate and adaptive immune responses including the enhancement of T cell proliferation and cytokine production.