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A novel surface molecule homologous to the p58/p50 family of receptors is selectively expressed on a subset of human natural killer cells and induces both triggering of cell functions and proliferation
Author(s) -
Bottino Cristina,
Sivori Simona,
Vitale Massimo,
Cantoni Claudia,
Falco Michela,
Pende Daniela,
Morelli Luigia,
Augugliaro Raffaella,
Semenzato Gianpietro,
Biassoni Roberto,
Moretta Lorenzo,
Moretta Alessandro
Publication year - 1996
Publication title -
european journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 201
eISSN - 1521-4141
pISSN - 0014-2980
DOI - 10.1002/eji.1830260823
Subject(s) - biology , receptor , microbiology and biotechnology , monoclonal antibody , antibody , immunology , genetics
Abstract Human natural killer (NK) cells express inhibitory (p58) or activatory (p50) receptors for HLA‐C alleles. Here, we describe a novel member of the p58/p50 family that is expressed by a subset of NK cells in about one third of donors. This molecule, termed p50.3, mediates NK cell triggering as revealed by the induction of intracellular free calcium mobilization, cytokine release and cytotoxicity. In addition, anti‐p50.3 monoclonal antibody (mAb) induced a selective, strong proliferation of p50.3 + NK cells in peripheral blood lymphocytes. Although p50.3 molecules do not appear to display an obvious HLA class I specificity, they are usually coexpressed with known inhibitory receptors for HLA class I alleles. mAb‐mediated cross‐linking of these receptors leads to inhibition of the anti‐p50.3 mAb‐induced NK cell activation and proliferation. Surface p50.3 molecules are glycoproteins of ∼ 55–58 kDa which, upon deglycosylation, display a relative molecular mass of 36 kDa, similar to that of deglycosylated (activatory) p50 receptors. Analysis of the two‐dimensional peptide maps of the 50.3 molecules revealed a high homology with the other HLA‐C‐specific p58/p50 receptors. The use of a set of oligodeoxynucleotide primers, previously shown to amplify the activatory (p50) forms of HLA‐C‐specific receptors, consistently amplified in p50.3 + clones a cDNA sequence termed KKA3. This sequence belongs to the p58/p50 multigene family, that encodes for a transmembrane protein specifically stained by anti‐p50.3 mAb in cell transfectants. Similar to p50 molecules, the KKA3‐encoded molecules are characterized by two extracellular immunoglobulin‐like domains, by the presence of a lysine in the transmembrane region and a short (39 amino acids) cytoplasmic tail which does not contain immune receptor tyrosine‐based activation motifs (ITAM)‐like sequences.