RT info:eu-repo/semantics/article T1 CD84 Functions as a homophilic adhesion molecule and enhances IFN- g secretion:adhesion is mediated by Ig-like domain 1 A1 Martín, Margarita A1 Romero, Xavier A1 Fuente García, Miguel Ángel de la A1 Tovar, Victoria A1 Zapater, Nuria A1 Esplugues, Enric A1 Pizcueta, Pilar A1 Bosch, Jaime A1 Engel, Pablo K1 Biología molecular AB CD84 is a member of the CD2 subset of the Ig superfamily of cell surface molecules. Its cytoplasmic tail binds to Src homology 2 domain-containing protein 1A (signaling lymphocytic activation molecule-associated protein), a protein encoded by the X-linked lymphoproliferative disease gene. It is preferentially expressed on B lymphocytes, monocytes, and platelets. We show that it is also expressed on thymocytes and T cells. CD84 was positive on CD4 CD8 thymocytes, and its expression decreased with cell maturation. It is expressed on mature T cells preferentially on CD45RO . To identify the CD84 ligand, we generated a solubleIg fusion protein containing the human CD84 extracellular domains (CD84-Ig). Because receptor-ligand interactions occur between several members of this subfamily, we assayed CD84-Ig binding with all members of the CD2 family. CD84-Ig bound to CD84-transfected cells, whereas no binding was detected with cells expressing other CD2 subfamily receptors, showing that CD84 binds to itself. Anti-CD84 mAbs recognizing epitopes wholly within domain 1 of CD84 blocked the binding of the CD84-Ig fusion protein to CD84-transfected cells and platelets. Data from CD84 domain human/mouse chimeras further revealed that only the first extracellular domain of the molecule is involved in the ligand receptor recognition. The CD84-CD84 interaction was independent of its cytoplasmic tail. Finally, concurrent ligation of human CD84 with mAbs or CD84-Ig and CD3 enhanced IFN-secretion in human lymphocytes. Thus, CD84 is its own ligand and acts as a costimulatory molecule. PB American Association of Immunologists SN 0022-1767 YR 2001 FD 2001 LK http://uvadoc.uva.es/handle/10324/10152 UL http://uvadoc.uva.es/handle/10324/10152 LA eng NO The Journal of Immunology 2001, 167(7): 3668–3676. NO Producción Científica DS UVaDOC RD 26-abr-2024