Vimentin expressed on Mycobacterium tuberculosis-infected human monocytes is involved in binding to the NKp46 receptor.
We previously showed that human NK cells used the NKp46 receptor to lyse Mycobacterium tuberculosis H37Ra-infected monocytes. To identify ligands on H37Ra-infected human mononuclear phagocytes, we used anti-NKp46 to immunoprecipitate NKp46 from NK cells bound to its ligand(s) on H37Ra-infected monocytes. Mass spectrometry analysis identified a 57-kDa molecule, vimentin, as a putative ligand for NKp46. Vimentin expression was significantly up-regulated on the surface of infected monocytes, compared with uninfected cells, and this was confirmed by fluorescence microscopy. Anti-vimentin antiserum inhibited NK cell lysis of infected monocytes, whereas antiserum to actin, another filamentous protein, did not. CHO-K1 cells transfected with a vimentin construct were lysed much more efficiently by NK cells than cells transfected with a control plasmid. This lysis was inhibited by mAb-mediated masking of NKp46 (on NK cells) or vimentin (on infected monocytes). ELISA and Far Western blotting showed that recombinant vimentin bound to a NKp46 fusion protein. These results indicate that vimentin is involved in binding of NKp46 to M. tuberculosis H37Ra-infected mononuclear phagocytes.
Garg
Ankita
A
Center for Pulmonary and Infectious Disease Control, University of Texas Health Center, 11937 U.S. Highway 271, Tyler, TX 75708, USA.
Barnes
Peter F
PF
Porgador
Angel
A
Roy
Sugata
S
Wu
Shiping
S
Nanda
Jagpreet S
JS
Griffith
David E
DE
Girard
William M
WM
Rawal
Nenoo
N
Shetty
Sreerama
S
Vankayalapati
Ramakrishna
R
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D026481:Blotting, Far-Western; D016466:CHO Cells; D002462:Cell Membrane / Q000737:chemistry; D006224:Cricetinae; D003412:Cricetulus; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D047468:Immunoprecipitation; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology; D008024:Ligands; D009000:Monocytes / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology*; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D055627:Natural Cytotoxicity Triggering Receptor 1; D010586:Phagocytes / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology; D010587:Phagocytosis / Q000187:drug effects; D025941:Protein Interaction Mapping; D011971:Receptors, Immunologic / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014746:Vimentin / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000378:metabolism*
D000906:Antibodies; D008024:Ligands; C112260:NCR1 protein, human; D055627:Natural Cytotoxicity Triggering Receptor 1; D011971:Receptors, Immunologic; D011993:Recombinant Fusion Proteins; D014746:Vimentin