Instrumentation

Helios uses CyTOF® technology to enable deep profiling of translational and clinical research samples across a range of cell surface and intracellular markers. CyTOF® is a variation of flow cytometry in which antibodies are labeled with heavy metal ion tags rather than fluorochromes.  

Since its invention, flow cytometry has become the method of choice for providing multidimension cell expression data at single-cell resolution by utilizing antibodies conjugated to fluorescent tags. Technological advancements, including additional lasers, fluorochromes, detection and analysis methods, flow panels are generally limited to <30 markers. Compensation matrices account for the overlap in the emissions spectra of each fluorochrome and with each additional parameter these matrices increase in complexity, reducing resolution and potentially excluding some events.

Mass cytometry is the fusion of flow cytometry and mass spectrometry, replacing fluorescent tags with metal isotopes and essentially eliminated the need for compensation while increasing the number of targets to 45+. Metal-conjugated antibodies provide the same resolution and sensitivity of flow cytometry, while nearly eliminating the need for compensation. Additionally, metal-conjugated antibodies are often more stable than their fluorescent counterparts, particularly tandem dyes.

As a developing field, standardization of experimental controls and data analysis are still being established. The number of available metal isotopes used for detection continues to increase, and currently mass cytometry is the first technology capable of 50-plex cytometry panels.

Hyperion Imaging System™ for Imaging Mass Cytometry is a highly multiplexed, antibody-based imaging system, that combines the spatial resolution of IHC with the multiplex aspects of flow cytometry. Coupled with a laser ablation unit, IMC allows for the analysis of 35+ targets in a single tissue sample, with subcellular resolution.

Most previous studies aiming at the characterization of the cellular composition and interactions with and within the immune microenvironment (IME) have used methods such as immunohistochemistry (IHC), flow cytometry and gene expression analysis. These methods have several limitations ranging from impaired reproducibility to the limited number of markers that can be assessed simultaneously. While IHC or immunofluorescence-based techniques can be used to study tissue architecture, multiplex experiments beyond 6-8 markers are not routinely feasible. Flow cytometry is capable of a higher degree of multiplexing; however, it sacrifices spatial information. RNA expression is unable to provide cellular level resolution and single cell RNA sequencing does not provide spatial information. Imaging mass cytometry (IMC) uses metal-tagged antibodies to label proteins of interest in a tissue sample. The metal tags allow for detection of labeled material using mass cytometry.