title: Flow cytometry and spectral imaging multiphoton microscopy analysis of CD36 expression with quantum dots 605 of untreated and 7-ketocholesterol-treated human monocytic cells.
abstract: OBJECTIVE
  To evaluate CD36 expression with quantum dots 605 (QDs 605) on untreated and 7-ketocholesterol (7KC)-treated monocytic U937 cells by flow cytometry (FCM) and confocal and multiphoton laser scanning microscopy (CLSM).
  
  
  METHODS
  Cells were analyzed by CLSM, following flow cytometric quantification of CD36 expression and 7KC uptake. Image sequences were obtained by spectral analysis in monophoton and multiphoton CLSM and analyzed by the factor analysis of medical image sequences (FAMIS) algorithm to differentiate emission spectra. In CLSM analysis, cell deposits were screened in ultraviolet excitation modes to optimize the possibilities of QDs 605 and have the benefit of nuclei counterstaining by DAPI.
  
  
  RESULTS
  FCM and CLSM reveal the expression of CD36 by means of QDs 605. FCM provides information on 7KC uptake. CLSM provides the localization of 7KC vs. DAPI. As factor curves and images show the red, narrow emission of QDs 605 vs. violet and blue emissions of 7KC and DAPI, respectively, a reliable identification of CD36 is obtained.
  
  
  CONCLUSIONS
  QDs 605 are useful tools to perform antigenic expression in FCM and CLSM. Moreover, CLSM and subsequent spectral analysis provide a more specific characterization of QDs 605 fluorescent emission in the UV excitation mode and a simultaneous identification of 7KC.
authors.affiliation: National Institute of Health and Medical Research, U678/Mixed Research Unit S UPMC, Paris, France. kahn@imed.jussieu.fr
authors.forename: Edmond
authors.initials: E
authors.lastname: Kahn
authors.forename: Franck
authors.initials: F
authors.lastname: Ménétrier
authors.forename: Anne
authors.initials: A
authors.lastname: Vejux
authors.forename: Thomas
authors.initials: T
authors.lastname: Montange
authors.forename: Dominique
authors.initials: D
authors.lastname: Dumas
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Riedinger
authors.forename: Frédérique
authors.initials: F
authors.lastname: Frouin
authors.forename: Yves
authors.initials: Y
authors.lastname: Tourneur
authors.forename: Frédéric
authors.initials: F
authors.lastname: Brau
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Stoltz
authors.forename: Gérard
authors.initials: G
authors.lastname: Lizard
mesh_terms: D000465:Algorithms; D018955:CD36 Antigens / Q000032:analysis* / Q000378:metabolism; D002478:Cells, Cultured; D005434:Flow Cytometry; D006801:Humans; D007653:Ketocholesterols / Q000494:pharmacology*; D036641:Microscopy, Fluorescence, Multiphoton; D009000:Monocytes / Q000187:drug effects* / Q000276:immunology; D017785:Photons; D045663:Quantum Dots; D020298:U937 Cells
chemical_list: D018955:CD36 Antigens; D007653:Ketocholesterols; C003001:7-ketocholesterol