title: The influence of calcium, sodium, and the Na+/Ca2+ antiport on susceptibility to cytolysin/perforin-mediated cytolysis.
abstract: In NK cell-mediated cytolysis, the degranulation of the NK cell, and the binding and polymerization of its effector molecule cytolysin/perforin, are Ca2+ dependent. To determine if increases in the target cell free intracellular Ca2+ concentration ([Ca2+]i) are also important for cytotoxicity, we examined the effects of Ca2+ substitutes, promotors of Ca2+ influx; and inhibitors of Ca2+ efflux on the cytolysis mediated by purified cytolysin. Ca2+ promoted cytolysin-mediated cytolysis but could also inactivate cytolysin on preincubation in the absence of target cells. Ba2+ and Sr2+ could not alone promote cytolysin-mediated cytolysis but did enhance Ca2(+)-driven cytolysis. Preincubation with Ba2+ and Sr2+ did not inactivate cytolysin. One interpretation which these results suggested was that neither Ba2+ nor Sr2+ were involved in cytolysin polymerization and pore formation, but could act intracellularly as Ca2+ analogs once pore formation had occurred. The synergistic interaction of cytolysin and the Ca2+ ionophore A23187 further supported a role for increased [Ca2+]i in cytolysis. Inhibitors of Na+/Ca2+ exchange, namely low Na+ medium, ouabain, and the amiloride analogs 2',4'-dimethylbenzamil, 5-(N-4-chlorobenzyl)-2',4'dimethylbenzamil, and alpha-phenylbenzamil all markedly enhanced cytolysin-mediated cytolysis. These results support the hypothesis that the Ca2+ dependency of NK cell- and cytolysin-mediated cytolysis is related to increases in target cell [Ca2+]i. Furthermore, they indicate that Na+/Ca2+ exchange is an important counterlytic mechanism.
authors.affiliation: Manitoba Institute of Cell Biology, University of Manitoba, Winnipeg, Canada.
authors.forename: R P
authors.initials: RP
authors.lastname: Kraut
authors.forename: D
authors.initials: D
authors.lastname: Bose
authors.forename: E J
authors.initials: EJ
authors.lastname: Cragoe
authors.forename: A H
authors.initials: AH
authors.lastname: Greenberg
mesh_terms: D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001464:Barium / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D002352:Carrier Proteins / Q000502:physiology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects*; D003602:Cytotoxicity, Immunologic; D003603:Cytotoxins / Q000633:toxicity*; D007694:Killer Cells, Natural / Q000502:physiology*; D008562:Membrane Glycoproteins; D008565:Membrane Proteins / Q000502:physiology* / Q000633:toxicity*; D051379:Mice; D010042:Ouabain / Q000494:pharmacology; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D012964:Sodium / Q000494:pharmacology*; D019831:Sodium-Calcium Exchanger; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors; D013324:Strontium / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
chemical_list: D002352:Carrier Proteins; D003603:Cytotoxins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D052899:Pore Forming Cytotoxic Proteins; D019831:Sodium-Calcium Exchanger; D054353:Perforin; C053494:2',4'-dimethylbenzamil; D001464:Barium; D000001:Calcimycin; D010042:Ouabain; D000584:Amiloride; D012964:Sodium; D014700:Verapamil; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium; D013324:Strontium