title: Fluorescence analysis of size distribution and mode of dye release from carboxyfluorescein-loaded vesicles: application to the study of complement-membrane interactions.
abstract: We wish to report a novel method for visualizing large unilamellar vesicles loaded with a fluorescent dye and for monitoring changes in the size distribution as well as state of aggregation of such dye-loaded liposomes. In addition, we demonstrate that this method can be used to distinguish between all-or-none release of dye and graded release of dye from individual vesicles. Using this technique, we have characterized complement-mediated release of carboxyfluorescein from large unilamellar vesicles and have found that C5-8 complexes mediate a graded release of dye while C5-9 complexes cause an all-or-none release. Furthermore, complement appears to preferentially attack the medium to larger-sized vesicles in our population of large unilamellar vesicles while smaller vesicles appear to be selectively spared.
authors.affiliation: Department of Biochemistry, Uniformed Services University of the Health Sciences, Bethesda, MD.
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Liu
authors.forename: R
authors.initials: R
authors.lastname: Solow
authors.forename: V W
authors.initials: VW
authors.lastname: Hu
mesh_terms: D002784:Cholesterol; D015938:Complement Membrane Attack Complex; D003165:Complement System Proteins / Q000502:physiology*; D004134:Dimyristoylphosphatidylcholine; D005452:Fluoresceins; D066298:In Vitro Techniques; D008081:Liposomes; D010539:Permeability; D013050:Spectrometry, Fluorescence
chemical_list: D015938:Complement Membrane Attack Complex; D005452:Fluoresceins; D008081:Liposomes; C024098:6-carboxyfluorescein; D003165:Complement System Proteins; D002784:Cholesterol; D004134:Dimyristoylphosphatidylcholine