High-Dimensional Immunophenotyping with 37-Color Panel Using Full-Spectrum Cytometry

Immunophenotyping challenging tissue types using high-dimensional full spectrum flow cytometry

Technological advancements in fluorescence flow cytometry and an ever-expanding understanding of the complexity of the immune system, have led to the development of large flow cytometry panels, reaching up to 40 markers at the single-cell level. Full spectrum flow cytometry, that measures the full emission range of all the fluorophores present in the panel instead of only the emission peaks is now routinely used in many laboratories internationally, and the demand for this technology is rapidly increasing. With the capacity to use larger and more complex staining panels, optimized protocols are required for the best panel design, panel validation and high-dimensional data analysis outcomes. In addition, for ex vivo experiments, tissue preparation methods for single-cell analysis should also be optimized to ensure that samples are of the highest quality and are truly representative of tissues in situ. Here we provide optimized step-by-step protocols for full spectrum flow cytometry panel design, tissue digestion and panel optimization to facilitate the analysis of challenging tissue types.

Development of Spectral Imaging Cytometry

Spectral flow cytometry is a new technology that enables measurements of fluorescent spectra and light scattering properties in diverse cellular populations with high precision. Modern instruments allow simultaneous determination of up to 40+ fluorescent dyes with heavily overlapping emission spectra, discrimination of autofluorescent signals in the stained specimens, and detailed analysis of diverse autofluorescence of different cells-from mammalian to chlorophyll-containing cells like cyanobacteria. In this paper, we review the history, compare modern conventional and spectral flow cytometers, and discuss several applications of spectral flow cytometry.

Demands and technical developments of clinical flow cytometry with emphasis in quantitative, spectral, and imaging capabilities

As the gold-standard method for single-cell analysis, flow cytometry enables high-throughput and multiple-parameter characterization of individual biological cells. This review highlights the demands for clinical flow cytometry in laboratory hematology (e.g., diagnoses of minimal residual disease and various types of leukemia), summarizes state-of-the-art clinical flow cytometers (e.g., FACSLyricTM by Becton Dickinson, DxFLEX by Beckman Coulter), then considers innovative technical improvements in flow cytometry (including quantitative, spectral, and imaging approaches) to address the limitations of clinical flow cytometry in hematology diagnosis. Finally, driven by these clinical demands, future developments in clinical flow cytometry are suggested.

iCoreDrop: A robust immune monitoring spectral cytometry assay with six open channels for biomarker flexibility

Recent advances in spectral cytometry have extended our ability to monitor immune cell subsets and activation status while simultaneously improving rare population detection. However, technical challenges in reference control selection and autofluorescence extraction serve as barriers to broad application of spectral flow cytometry. Furthermore, the complexity of spectral cytometry panel development limits the adaptation of established assays. Here, we describe the development of a spectral immunophenotyping assay with robust drop-in capability to enable biomarker interrogation flexibility. The immune monitoring core (iCore), which can be used in part or total, captures broad and granular immune subsets across T cells, B cells, NK cells, monocytes, dendritic cells, and granulocytes in peripheral whole blood. Additional user-selected biomarkers can be dropped in (Drop) using channels BV421, Alexa Fluor 488, PE, PE-Cy7, APC, and APC-Cy7. A comprehensive assessment of reagent and panel performance was conducted, including reference control comparison and optimal autofluorescence (AF) extraction on the 5-laser Cytek Aurora system for healthy donor blood. Assay precision and stability analyses revealed robust intra-assay precision, with 95% of 83 distinct population gates having <20% CV. In the presence of additional drop-in markers in two different settings, a T cell module and a myeloid/B cell module, the drop-in channels themselves achieved <20% CV across 12 out of 13 additionally queried population gates. Overall, establishment of optimal unmixing practices will enable widespread adoption of spectral cytometry assays.