title: Increased cell surface exposure of phosphatidylserine on propidium iodide negative thymocytes undergoing death by necrosis.
abstract: Phosphatidylserine (PS) exposure on propidium iodide negative cells using FITC labelled annexin-V has been used to quantify apoptosis in vitro and in vivo. Detection of PS within cells undergoing necrosis is also possible if labelled annexin-V specific for PS enters the cell following early membrane damage. Necrotic or late apoptotic cells can be excluded from flow cytometric analysis using propidium iodide which enters and stains cells with compromised membrane integrity. Here we show that thymocytes undergoing death exclusively by necrosis show early exposure of PS prior to loss of membrane integrity. This early exposure of PS occurs in cells treated with agents which both raise intracellular calcium levels and are also capable of interacting with protein thiol groups. We also demonstrate that PS exposure in thymocytes induced to undergo apoptosis by three different agents does not correlate with calcium rises but correlates with and precedes DNA fragmentation.
authors.affiliation: Division of Immunology and Cell Biology, John Curtin School of Medical Research, Australian National University, PO Box 334, Canberra, Australia. Paul.Waring@anu.edu.au
authors.forename: P
authors.initials: P
authors.lastname: Waring
authors.forename: D
authors.initials: D
authors.lastname: Lambert
authors.forename: A
authors.initials: A
authors.lastname: Sjaarda
authors.forename: A
authors.initials: A
authors.lastname: Hurne
authors.forename: J
authors.initials: J
authors.lastname: Beaver
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D053938:DNA Fragmentation / Q000187:drug effects; D003907:Dexamethasone / Q000494:pharmacology; D004220:Disulfides / Q000494:pharmacology; D005912:Gliotoxin / Q000494:pharmacology; D066298:In Vitro Techniques; D051379:Mice; D008807:Mice, Inbred BALB C; D009336:Necrosis; D010718:Phosphatidylserines / Q000378:metabolism*; D011419:Propidium; D011725:Pyridines / Q000494:pharmacology; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D013601:T-Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D019284:Thapsigargin / Q000494:pharmacology
chemical_list: D004220:Disulfides; D010718:Phosphatidylserines; D011725:Pyridines; D013439:Sulfhydryl Reagents; C007542:4,4'-dipyridyl disulfide; D011419:Propidium; D005912:Gliotoxin; D019284:Thapsigargin; D003907:Dexamethasone; D002118:Calcium