Mass cytometry, driven by CyTOF® technology, uses antibodies labeled with monoisotopic metal tags, enabling high-resolution identification of discrete immune cell phenotypes and their subpopulations. The advent of the antibody labeling method for seven cadmium and four platinum isotopes has enabled mass cytometry to expand the multiparametric characterization of single cells to 57 parameters. The new possibilities afforded by these additional metal-tagged antibodies can be seen in their ability to both increase existing panel size and support new applications for innovative research discoveries. We have previously demonstrated that cadmium-labeled antibodies can effectively be used for live-cell barcoding (LCB) of human peripheral blood mononuclear cells (PBMC) with antibodies targeting the pan-leukocyte protein CD45. As LCB does not require prior fixation of cells, a major advantage of this approach is that it preserves the ability to multiplex-stain fix-sensitive epitopes.
In this study, we have expanded upon the LCB approach by combining both cadmium and platinum-labeled anti-CD45 antibodies in a 7-choose-3, 35-plex configuration to allow for added flexibility and customization of antibody panels. Furthermore, we observed similar results in LCB data quality on the new automated-acquisition CyTOF system when compared to the Helios™ mass cytometer. This enables the ability to run highly multiplexed barcoded samples for extended acquisition periods with less time needed supervising the instrument. Finally, we show the use of LCB in human whole blood samples stained with the Maxpar® Direct™ Immune Profiling Assay™. Overall, this work demonstrates added customizability and compatibility with existing workflows for live-cell barcoding, a powerful technique for improving data quality and increasing mass cytometry throughput.