title: Silver nanoparticles for the detection of cell surface antigens in mass cytometry.
abstract: Mass cytometry has pioneered >40-parameter single-cell analyses that allow for the characterization of complex cellular networks at unprecedented depth. Up to 135 parameters can be simultaneously detected, but limited availability of metal tags suitable for labeling of specific probes prevents optimal exploitation of the analytical capacity of mass cytometers. To this end, we here establish the application of elemental silver nanoparticles (AgNP) of different size for reporting cell surface antigens on human leukocytes in mass cytometry assays. The mass channels at 107 Da and 109 Da are uniquely occupied by silver isotopes and do not interfere with other mass cytometry reagents. Streptavidin-coated AgNP (SA-AgNP) facilitated distinct and specific detection of various antigens, such as CD8, CD244 and CD294 on peripheral blood leukocytes pre-incubated with respective biotinylated primary antibodies. Signal intensities elicited by 40 nm-sized AgNP allowed specific detection of the low abundance antigen CD25 on both, peripheral blood regulatory T cells and CD25loCD127+CD4+T cells, enabling their distinct clustering in viSNE plots. SA-AgNP were of high elemental purity, showed minor background binding to cells in immunoassays, and were compatible with previously established staining protocols for PBMC and leukocytes, facilitating their use in complex mass cytometry panels. Considering the synthesis of AgNP from isotopically purified silver, the usage of AgNP extends the analytical capacity of mass cytometry panels by one, prospectively two, additional parameters, suitable for the detection of cellular targets of low abundance. © 2016 International Society for Advancement of Cytometry.
authors.affiliation: German Rheumatism Research Center (DRFZ), a Leibniz Institute, Berlin, Germany.
authors.forename: Axel Ronald
authors.initials: AR
authors.lastname: Schulz
authors.affiliation: German Rheumatism Research Center (DRFZ), a Leibniz Institute, Berlin, Germany.
authors.forename: Silke
authors.initials: S
authors.lastname: Stanislawiak
authors.affiliation: German Rheumatism Research Center (DRFZ), a Leibniz Institute, Berlin, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Baumgart
authors.affiliation: German Rheumatism Research Center (DRFZ), a Leibniz Institute, Berlin, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Grützkau
authors.affiliation: German Rheumatism Research Center (DRFZ), a Leibniz Institute, Berlin, Germany.
authors.forename: Henrik E
authors.initials: HE
authors.lastname: Mei
mesh_terms: D000954:Antigens, Surface / Q000276:immunology / Q000302:isolation & purification*; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D053768:Metal Nanoparticles / Q000737:chemistry; D012834:Silver / Q000737:chemistry; D059010:Single-Cell Analysis
chemical_list: D000954:Antigens, Surface; D012834:Silver
keywords: CD25; CyTOF; immune monitoring; immune phenotyping; mass cytometry; silver nanoparticles