title: Whole-cell MALDI-TOF MS: a new tool to assess the multifaceted activation of macrophages.
abstract: Whole-cell MALDI-TOF MS is routinely used to identify bacterial species in clinical samples. This technique has also proven to allow identification of intact mammalian cells, including macrophages. Here, we wondered whether this approach enabled the assessment human macrophages plasticity. The whole-cell MALDI-TOF spectra of macrophages stimulated with IFN-γ and IL-4, two inducers of M1 and M2 macrophage polarisation, consisted of peaks ranging from 2 to 12 kDa. The spectra of unstimulated and stimulated macrophages were clearly different. The fingerprints induced by the M1 agonists, IFN-γ, TNF, LPS and LPS+IFN-γ, and the M2 agonists, IL-4, TGF-β1 and IL-10, were specific and readily identifiable. Thus, whole-cell MALDI-TOF MS was able to characterise M1 and M2 macrophage subtypes. In addition, the fingerprints induced by extracellular (group B Streptococcus, Staphylococcus aureus) or intracellular (BCG, Orientia tsutsugamushi, Coxiella burnetii) bacteria were bacterium-specific. The whole-cell MALDI-TOF MS fingerprints therefore revealed the multifaceted activation of human macrophages. This approach opened a new avenue of studies to assess the immune response in the clinical setting, by monitoring the various activation patterns of immune cells in pathological conditions.
authors.affiliation: Unité de Recherche sur les Maladies Infectieuses Tropicales et Emergentes, Aix Marseille Université, CNRS UMR 7278, INSERM U1095, Marseille, France.
authors.forename: Richard
authors.initials: R
authors.lastname: Ouedraogo
authors.forename: Aurélie
authors.initials: A
authors.lastname: Daumas
authors.forename: Eric
authors.initials: E
authors.lastname: Ghigo
authors.forename: Christian
authors.initials: C
authors.lastname: Capo
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Mege
authors.forename: Julien
authors.initials: J
authors.lastname: Textoris
mesh_terms: D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation / Q000502:physiology*; D008264:Macrophages / Q000145:classification / Q000187:drug effects / Q000276:immunology*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D013292:Streptococcus agalactiae / Q000276:immunology; D053773:Transforming Growth Factor beta1 / Q000494:pharmacology
chemical_list: D008070:Lipopolysaccharides; D053773:Transforming Growth Factor beta1; D015847:Interleukin-4; D007371:Interferon-gamma