P49, a putative HLA-G1 specific inhibitory NK receptor belonging to the immunoglobulin Superfamily.
NK cells display several killer inhibitory receptors (KIRs) specific for different alleles of major histocompatibility complex (MHC) class I molecules. A family of KIRs are represented by type I transmembrane proteins belonging to the Immunoglobulin Superfamily (Ig-SF). In the present study we describe a cDNA, termed cl.15.212, that encodes for a type I transmembrane protein displaying approximately 50% sequence homology with other Ig-SF members. The protein encoded by cl.15.212 (termed p49 according to its apparent molecular weight of 49 kDa) is characterized by two extracellular Ig-like domains, a 115-amino acid cytoplasmic tail containing a single immuno-receptor tyrosine-based inhibitory motif (ITIM) typical of KIR. Different from the other KIRs, the cl.15.212 transcript is expressed by all NK cells and by a fraction of T-cell clones expressing KIR. To determine the specificity of the cl.15.212-encoded receptor, we generated a chimeric protein, formed by the ectodomain of p49 and the Fc portion of human IgG1 (p49-Fc). Soluble molecules bound efficiently to LCL721.221 (221) cells transfected with HLA-G1, -A3, -B46 alleles and weakly to the -B7 allele. On the other hand, they did not bind to 221 cells either untransfected or transfected with HLA-A2, -B51, -Cw3, or-Cw4.
Cantoni
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C
Istituto Scientifico Tumori and Laboratorio di Immunopatologia, Centro Biotecnologie, Genova, Italy.
Falco
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M
Pessino
A
A
Moretta
A
A
Moretta
L
L
Biassoni
R
R
D000483:Alleles; D000818:Animals; D019556:COS Cells; D015870:Gene Expression; D006801:Humans; D007136:Immunoglobulins / Q000737:chemistry; D007694:Killer Cells, Natural / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011971:Receptors, Immunologic / Q000145:classification / Q000235:genetics / Q000276:immunology*; D012995:Solubility
D007136:Immunoglobulins; C113001:P49 natural killer cell receptor; D011971:Receptors, Immunologic