Mass Spectrometry Goes With the Flow

Study Aim Numerous technical advances have characterized the proteomic field since it was first named in 1994.1 Some of the techniques that have driven the field, such as mass spectrometry, have undergone considerable technical development over the years. For instance, time-of-flight (TOF) mass analyzers date back to the first half of the 20th century.2 In the study described by Newell and colleagues3 a newly developed hybrid instrument, which combines a flow-cytometer with a TOF analyzer (cyTOF), was employed to characterize CD8+ T lymphocytes in humans. Notably, contrary to traditional flow-cytometry, where multiplexing (monitoring multiple analytes at the same time) is limited by the partial overlap of excitation/emission spectra of the different fluorophores, in this case the reporters that can be measured are many and more selective (little to no cross-talk). Finally, although, to my knowledge, this cutting-edge technique has not been applied yet in the cardiovascular research field, perhaps 1 application can be anticipated, in the field of cardiac regeneration. ### How Was the Aim Achieved? Newell and colleagues went about describing the heterogeneity of CD8+ T lymphocytes by enriching them from the peripheral blood of platelet aphaeresis donors. Two different approaches were employed to characterize the CD8+ population. One used mass cytometry, also referred to as cyTOF, due to the mass analyzer employed. In proteomics, TOF analyzers are associated most commonly to matrix assisted laser …