Characterization of MAX.3 antigen, a glycoprotein expressed on mature macrophages, dendritic cells and blood platelets: identity with CD84

Abstract

MAX.3 is a monoclonal antibody that preferentially reacts with mature macrophages (MAC), monocyte-derived dendritic cells, megakaryocytes and platelets. In this study, we describe the characterization, purification and identification of the MAX.3 antigen. Immunoprecipitation and SDS/PAGE revealed different molecular masses of MAX.3 antigen in MAC (60-90 kDa) and platelets (58-64 kDa), whereas a similar size (45 kDa) was observed in both cell types after digestion with N-glycosidase F. Lectin affinity and sequential treatment with different glycosidases suggests complex type glycosylation of MAX.3 antigen in MAC and hybrid type glycosylation in platelets. Amino acid sequencing led to the identification of a corresponding cDNA clone and showed its identity to the sequence of the CD84 antigen, a member of the CD2 family of cell surface molecules. MAX.3/CD84 was further studied by immunohistochemistry and a variable expression was found on tissue MAC, confirming this antigen to be mainly a marker for MAC in situ.

The CD2 Family of Natural Killer Cell Receptors

“…CD84 engages in homophilic interactions and is expressed on B cells, T cells, DCs, monocytes, platelets, and granulocytes (Krause et al 2000;Zaiss et al 2003;Romero et al 2004). CD84 expression is either very low or absent on resting human NK cells (Tangye et al 2002;Romero et al 2004).…”

Minding the gaps to promote thrombus growth and stability

“…Signaling lymphocytic activation molecule (SLAM; CD150) and CD84 are members of the CD2 family of homophilic adhesion molecules that have been studied extensively in lymphocytes, but have now been shown to be expressed in platelets as well (41)(42)(43). The members of the family are type 1 membrane glycoproteins in the Ig superfamily.…”

Platelet aggregation induces platelet aggregate stability via SLAM family receptor signaling

“…8,9 SAP/EAT-2 binding homophilic adhesion molecules of the family include SLAM (CD150, IPO-3), CD84 (Ly9B), Ly108 (NTB-A, SF2000), CRACC (CD2-like receptoractivating cytotoxic cells)/CS-1, and 2B4 (CD244, NAIL). Although CD84 was previously shown to be expressed at relatively higher levels on platelets than on T or B cells, 10 a role for SLAM family members in platelet biology has not been described.…”