CS1, a novel member of the CD2 family, is homophilic and regulates NK cell function.
CS1 is a novel member of the CD2 subset of immunoglobulin superfamily (IgSF) expressed on NK, T and stimulated B cells. The cytoplasmic domain of CS1 contains immunoreceptor tyrosine-based switch motif (ITSM) which is present in 2B4, SLAM and CD84. The signaling adaptor molecule SAP/SH2D1A, the defective gene in X-linked lymphoproliferative disease (XLPD), binds to ITSM and regulates immune cell function. However, recent studies indicate that CS1 may be regulated by a SAP-independent mechanism. In this study, we have examined the ligand specificity of CS1 and the effect of CS1 interaction with its ligand on the cytolytic activity of YT, a human NK cell line. Recombinant fusion protein, CS1-Ig, containing the CS1 extracellular domain and Fc portion of the human IgG bound cells transfected with CS1. CS1-Ig did not show any binding to cells expressing other members of the CD2 family. The cytolytic activity of YT was enhanced in presence of soluble CS1-Ig fusion protein. These results demonstrate that CS1 is a self-ligand and homophilic interaction of CS1 regulates NK cell cytolytic activity.
Kumaresan
Pappanaicken R
PR
Department of Molecular Biology and Immunology, Institute for Cancer Research, University of North Texas, Health Science Center 3500, Fort Worth 76017, USA.
Lai
Wayne C
WC
Chuang
Samuel S
SS
Bennett
Michael
M
Mathew
Porunelloor A
PA
D020816:Amino Acid Motifs; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D011971:Receptors, Immunologic / Q000737:chemistry / Q000276:immunology / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D000071176:Signaling Lymphocytic Activation Molecule Family
D011971:Receptors, Immunologic; D011993:Recombinant Fusion Proteins; C448987:SLAMF7 protein, human; D000071176:Signaling Lymphocytic Activation Molecule Family