Human NK cells lyse organ-specific endothelial cells: analysis of adhesion and cytotoxic mechanisms.
Human organ-specific microvascular endothelial cells (ECs) were established and used in the present study to investigate their susceptibility to natural killer cell line (NKL)-induced lysis. Our data indicate that although IL-2-stimulated NKL (NKL2) cells adhered to the human peripheral (HPLNEC.B3), mesenteric lymph node (HMLNEC), brain (HBrMEC), and lung (HLMEC) and skin (HSkMEC.2) ECs, they significantly killed these cells quite differently. A more pronounced lysis of OSECs was also observed when IL-2-stimulated, purified peripheral blood NK cells were used as effector cells. In line with the correlation observed between adhesion pattern and the susceptibility to NKL2-mediated killing, we demonstrated using different chelators that the necessary adhesion step was governed by an Mg(2+)-dependent, but Ca(2+)-independent, mechanism as opposed to the subsequent Ca(2+)-dependent killing. To identify the cytotoxic pathway used by NKL2 cells, the involvement of the classical and alternate pathways was examined. Blocking of the Ca(2+)-dependent cytotoxicity pathway by EGTA/MgCl(2) significantly inhibited endothelial target cell killing, suggesting a predominant role for the perforin/granzyme pathway. Furthermore, using confocal microscopy, we demonstrated that the interaction between NKL2 effectors and ECs induced cytochrome c release and Bid translocation in target cells, indicating an involvement of the mitochondrial pathway in NKL2-induced EC death. In addition, although all tested cells were sensitive to the cytotoxic action of TNF, no susceptibility to TRAIL or anti-Fas mAb was observed. The present studies emphasize that human NK cell cytotoxicity toward ECs may be a potential target to block vascular injury.
Bielawska-Pohl
Aleksandra
A
Institut National de la Santé et de la Recherche Médicale, Unité 487, Institut Gustave Roussy, Villejuif, France.
Crola
Claire
C
Caignard
Anne
A
Gaudin
Catherine
C
Dus
Danuta
D
Kieda
Claudine
C
Chouaib
Salem
S
D002413:Cations, Divalent / Q000737:chemistry; D002448:Cell Adhesion / Q000276:immunology; D002450:Cell Communication / Q000276:immunology; D016923:Cell Death / Q000276:immunology; D002460:Cell Line; D018920:Coculture Techniques; D045304:Cytochromes c / Q000378:metabolism; D003601:Cytotoxicity Tests, Immunologic / Q000379:methods; D003602:Cytotoxicity, Immunologic; D042783:Endothelial Cells / Q000166:cytology* / Q000276:immunology*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000276:immunology*; D053804:Granzymes; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology*; D008024:Ligands; D008213:Lymphocyte Activation / Q000276:immunology; D008928:Mitochondria / Q000201:enzymology / Q000378:metabolism; D009928:Organ Specificity / Q000276:immunology; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism / Q000502:physiology; D012697:Serine Endopeptidases / Q000502:physiology; D033081:Shear Strength; D013314:Stress, Mechanical
D002413:Cations, Divalent; D007376:Interleukin-2; D008024:Ligands; D018124:Receptors, Tumor Necrosis Factor; D045304:Cytochromes c; C509213:GZMB protein, human; D053804:Granzymes; D012697:Serine Endopeptidases