Customizing Maxpar Direct Immune Profiling Assay with Additional Surface Marker and Intracellular Cytokine Staining Workflows for Expanded Mass Cytometry Panels

Mass cytometry, or cytometry by time-of-flight (the basis for Fluidigm® CyTOF® technology), is a system for single-cell detection using antibodies tagged with metal probes. Without the need for compensation, the highly parametric Helios™ mass cytometer has a detection range of 135 distinct mass channels (75-209 Da). Optimized for mass cytometry, the Maxpar® Direct™ Immune Profiling Assay™ is a dry, metal-tagged antibody cocktail for immunophenotyping 37 immune cell populations found in human peripheral blood in a single tube. The Maxpar Direct Assay utilizes 31 mass channels for marker detection and live/dead viability staining, with at least 14 additional marker channels available from the Fluidigm catalog for flexible custom panel design. Here, we describe a workflow combining the assay with additional surface and intracellular cytokine antibodies for peripheral blood mononuclear cell (PBMC) staining using lanthanide-, bismuth-, and cadmium-tagged antibodies.