2F1 antigen, the mouse homolog of the rat "mast cell function-associated antigen", is a lectin-like type II transmembrane receptor expressed by natural killer cells.
Inhibitory lectin-like receptors expressed on the surface of hematopoietic cells are critically involved in regulation of their effector functions. Here we report that a novel mAb specific for mouse NK cells, 2F1, recognizes the mouse homolog of the mast cell function-associated antigen (MAFA), an inhibitory lectin-like transmembrane receptor expressed on rat mast cells. The 2F1 antigen (2F1-Ag) and rat MAFA are structurally highly conserved and contain a cytoplasmic motif similar to the immunoreceptor tyrosine-based inhibitory motif that is presumably utilized for inhibitory signaling. We also identified a human homolog that is closely related to the rodent MAFA/2F1-Ag proteins. Like rat MAFA, 2F1-Ag is probably encoded by a single gene, which exhibits relatively little polymorphism. Strikingly, while rat MAFA is considered a mast cell antigen, we have been unable to detect cell surface expression of 2F1-Ag by mouse mast cell lines, bone marrow-derived mast cells, or peritoneal mast cells. Furthermore, mouse bone marrow-derived mast cells were devoid of 2F1-Ag mRNA. Instead, we find that approximately 40% of mouse NK cells express 2F1-Ag. Thus, MAFA/2F1-Ag may modulate immunological responses on at least two different cell types bridging the specific and innate immune system.
Hanke
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Department of Molecular and Cell Biology, University of California, Berkeley 94720-3200, USA.
Corral
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Vance
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Raulet
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D000595:Amino Acid Sequence; D000818:Animals; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D037102:Lectins; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008969:Molecular Sequence Data; D011110:Polymorphism, Genetic; D051381:Rats; D011971:Receptors, Immunologic / Q000235:genetics* / Q000276:immunology; D016415:Sequence Alignment; D017421:Sequence Analysis; D015534:Trans-Activators
C113413:KLRG1 protein, human; C451496:Klrg1 protein, mouse; C094696:Klrg1 protein, rat; D037102:Lectins; D037181:Lectins, C-Type; D008562:Membrane Glycoproteins; D011971:Receptors, Immunologic; D015534:Trans-Activators