IsoPlexis: Leader in Single Cell Proteomics
IsoPlexis is the latest in a series of tools for use in biosciences, offering Single Cell functional proteomics analysis. The technology consists of three elements: chips, hardware and analysis software. As simplistic as this sounds, the device is capable of analysing Functional Immune Landscape (Single Cell Secretome), Intracellular Omics (Single Cell intracellular signalling/metabolome) and highly multiplexed Bulk ELISA on biofluids. These assays are performed fully automated from the point of chip loading until end of assay, and additionally, IsoSpeak software will process raw date into analysed and publishable graphs.
To illustrate the power of IsoPlexis technology, a recent publication in Nature Medicine (https://www.nature.com/articles/s41591-021-01436-0) can be illustrated. Utilising the IsoLight platform to analyse single cells, the researchers obtained PSI (Polyfunctional Strength Index) results utilising IsoPlexis’ IsoSpeak software, creating the published graph as is presented in Fig. 4j. All of these processes require no external analysis from other departments, optimising resources.
The aim of the Phase 1 trial was to assay the effects of a CD19/22 bi-specific CAR in prognosis by where CD19 depletion occurs in vivo, leading to diminished complete remission. One of the assays performed was stimulation of NALM6 (CD19, CD22 or CD19/22 double knockout) B cell leukemia precursor cell line by either purified CD4+ or CD8+ CAR-T cells (bi-specific CD19/22 or mono-specific CD22 CAR) to detect variations in single cell PSI.
It is clear that polyfunctionality of NALM6 cells was lower in the bi-specific CD19/22 CAR when compared to monospecific CD22 CAR-T stimulation of CD22 knockout NALM6 in both CD4+ and CD8+ purified CAR-T conditions. Furthermore, TNFα and IL2 were more potently secreted in CD22 competent NALM6 exposed to mono-specific CD22 CAR-T compared to the bi-specific.
This raises the question of potency vs redundancy of bi-specific vs mono-specific CAR-T, in which mono-specific had a more potent PSI, however upon depletion of target, PSI showed a strongly reduced secretory profile, which when compared to bi-specific CD19/22 CAR-T stimulation could maintain polyfunctionality in NALM6 with either CD19 or CD22 depletion. Furthermore, the researchers with regards to utilising IsoPlexis technology in CAR engineering state:
“engineering iterations should be guided by careful studies of single-cell CAR polyfunctionality incorporating cytokine production as a critical quality attribute”