title: Cutting edge: NTB-A activates NK cells via homophilic interaction.
abstract: NK cells are an important component of the innate immune system. Their activity is tightly regulated by activating and inhibitory surface receptors. However, the exact functions of many activating surface receptors, as well as their ligands, still remain to be elucidated. NTB-A is a receptor on the surfaces of human NK, T, and B cells, mediating a signal whose malfunction may be involved in X-linked lymphoproliferative disease. However, the ligand of NTB-A has remained elusive so far. Using trimeric recombinant proteins, we now show that NTB-A is its own ligand. Homophilic interaction of NTB-A enhances NK cell cytotoxicity and influences NK cell proliferation and IFN-gamma secretion. We suggest that NTB-A is an interlymphocyte signaling molecule, which serves to orchestrate the activities of immune cells.
authors.affiliation: Institute for Immunology, University of Heidelberg, Heidelberg, Germany.
authors.forename: Ruediger M
authors.initials: RM
authors.lastname: Flaig
authors.forename: Sebastian
authors.initials: S
authors.lastname: Stark
authors.forename: Carsten
authors.initials: C
authors.lastname: Watzl
mesh_terms: D015703:Antigens, CD; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic; D006023:Glycoproteins / Q000502:physiology*; D006801:Humans; D007136:Immunoglobulins / Q000502:physiology*; D007371:Interferon-gamma / Q000096:biosynthesis; D007694:Killer Cells, Natural / Q000276:immunology*; D008213:Lymphocyte Activation; D011956:Receptors, Cell Surface; D000071176:Signaling Lymphocytic Activation Molecule Family; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1
chemical_list: D015703:Antigens, CD; D006023:Glycoproteins; D007136:Immunoglobulins; D011956:Receptors, Cell Surface; C000604060:SLAMF6 protein, human; D000071176:Signaling Lymphocytic Activation Molecule Family; D000071177:Signaling Lymphocytic Activation Molecule Family Member 1; D007371:Interferon-gamma