title: Novel interaction between proliferating cell nuclear antigen and HLA I on the surface of tumor cells inhibits NK cell function through NKp44.
abstract: NK cell function is closely regulated by numerous inhibitory and activating receptors binding corresponding ligands on the surface of target cells, providing vital first line defenses against infections and cancer. NKp44, originally discovered as an activating NK cell receptor, was recently found to elicit inhibitory effects on NK cell effector function through recognition of cell surface PCNA. Other reports have pointed to potential associations between NKp44 and HLA I molecules, as well as HLA I and Damage Associated Molecular Pattern molecules (DAMPs) on the surface of tumor cells. In this report, we have identified novel interaction between HLA I and PCNA on the surface of human tumor cells by confocal microscopy and immunoprecipitation. In addition to previous reports, we show PCNA on the cell surface where novel association with HLA I does not require the presence of NKp44 expressing NK cells and occurs with endogenous PCNA. The association of HLA I and PCNA forms the inhibitory ligand for NKp44, resulting in inhibition of NK cell cytotoxicity. We further postulate NCR ligands are composed of DAMP molecules localized to the cell surface, colocalizing with HLA I, and potentially heparin sulfate proteoglycans.
authors.affiliation: Department of Molecular Biology and Immunology and Institute for Cancer Research, University of North Texas Health Science Center, Fort Worth, Texas, United States of America.
authors.forename: Nathan C
authors.initials: NC
authors.lastname: Horton
authors.forename: Stephen O
authors.initials: SO
authors.lastname: Mathew
authors.forename: Porunelloor A
authors.initials: PA
authors.lastname: Mathew
mesh_terms: D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism*; D002860:Chromium Radioisotopes / Q000378:metabolism; D017931:DNA Primers / Q000235:genetics; D005434:Flow Cytometry; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D007694:Killer Cells, Natural / Q000276:immunology*; D018613:Microscopy, Confocal; D055629:Natural Cytotoxicity Triggering Receptor 2 / Q000378:metabolism*; D009369:Neoplasms / Q000276:immunology* / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*
chemical_list: D002860:Chromium Radioisotopes; D017931:DNA Primers; D015395:Histocompatibility Antigens Class I; C112837:NCR2 protein, human; D055629:Natural Cytotoxicity Triggering Receptor 2; D018809:Proliferating Cell Nuclear Antigen