A practical guide to multiplexed mass cytometry.

Recent advances in inductively coupled plasma mass spectrometry (ICP-MS) as applied in mass cytometry, enabled its broad applicability to life science research. Mass cytometry enables the high-dimensional characterization of cellular systems by simultaneously measuring dozens of metal isotope reporter labeled antibodies bound to cell components. With the ability to simultaneously interrogate an unprecedented number of molecular components on a per cell basis, it offers the possibility to gain better understanding of single cell biology in heterogeneous samples. To upscale this single cell information to screening approaches by mass cytometry, a cell-based multiplexing technique, called mass-tag cellular barcoding (MCB), was developed. MCB enables the simultaneous analysis of multiple cell samples by using n metal ion tags to multiplex up to 2 (n) samples. Different mass tag combinations are used to label individual cell samples with a unique mass barcode that allows multiple samples to be combined and immunostained together for a single analysis on the mass cytometer. Taken together, MCB enables increased sample throughput, reduces antibody consumption, and increases the overall data quality. In this chapter, we describe the MCB to array the samples in a 96-well format that allows for medium-scale profiling/screening experiments to be run on a standard mass cytometer.