01.2018 | THE SCIENTIST 14A
h uman cell map is vital information for researchers designing
immunotherapies. To create these maps, scientists use techniques
such as flow cytometry and RNA sequencing to characterize immune
cells based on their physical properties. However, researchers have identified
numerous cells with identical surface marker phenotypes that show vast
functional diversity, highlighting a gap between the information provided by
these traditional techniques and the ability to characterize cell function.
Immune Therapy Advancement with IsoPlexis “Functional Phenotyping”
IsoPlexis’ single-cell functional proteomics platform fills this gap by providing
a more complete picture of how individual cell functionality provides critical
information missing from genotypes and marker expression through
“functional phenotyping.” The platform can identify functional differences in
phenotypically identical cells and characterize and measure cytokine secretion
in single cells. This allows scientists to uncover unique polyfunctional cellular
subsets that can produce multiple cytokines simultaneously. This technology
has advanced cancer immunology research and development of immune
therapies using T cells, CAR-T cells, TCR-T cells, NK cells, and more.
Insights into Biological Drivers of Anti-Tumor Response
Recently, IsoPlexis technology helped uncover highly polyfunctional CD4+ cell
subsets that conventional surface marker-based phenotyping techniques had
missed. In 2018, Rossi et al. published an article in the journalBlood^1 identifying
single-cell polyfunctionality as a potential predictor of patient response to
CAR-T cell therapy. By examining the CAR-T products from 20 lymphoma
patients, the researchers identified separate CD4+ and CD8+ subsets that
secreted granzyme B, IFN-γ, IL-5, IL-8, and MIP-1α in a polyfunctional manner.
In addition to these, the highly polyfunctional CD4+ cellular subset also
secreted IL-17A. Rossi et al. found that only 20% to 25% of all CAR-T product
cells were polyfunctional upon stimulation with CD19+ target cells. This range
of cytokine secretion from the rare polyfunctional CD4+ cells correlated to
driving effective and potent immune-mediated responses.
Further experiments revealed that cellular polyfunctionality associated
with clinical outcomes, including adverse effects such as cytokine release
syndrome and neurologic toxicity. This study outlined how functional
phenotyping could be a useful tool for discovering improved biomarkers of
response to treatment.
Identifying Unique Cell Subsets with Critical Roles in Immune Suppression
Immunotherapy research typically focuses on direct immune cell responses.
However, a study inBlood Cancer^2 from Chen et al. at the Mayo Clinic
explored how other cell types modulate immune cell responses. This
study used IsoPlexis’ single-cell functional proteomics technology to
study the biological and clinical relevance of signal regulatory protein-α
(SIRPα) expression in B-cell non-Hodgkin lymphoma (NHL). They found
and functionally characterized three monocyte/macrophage (Mo/MΦ)
subsets based on differences in CD14 and SIRPα expression levels. These
three subsets differed functionally in terms of cytokine secretion profiles,
phagocytosis properties, and how they regulated T cell activity. IsoPlexis’
single-cell proteomics technology revealed that the CD14+SIRPαhi subset
contained a higher number of polyfunctional cells than the other subsets.The CD14+SIRPαhi subset expressed common Mo/MΦ markers, suppressed
T cell function, and was correlated with poor prognosis in follicular
lymphoma patients. Conversely, the CD14-SIRPαlow subset expressed fewer
typical Mo/MΦ markers, stimulated T cell function, and correlated with
improved patient survival. This study identified unique Mo/MΦ subsets that
modulated cellular function and affected the immune response as a whole
based on their functional phenotypes.Powering Immune Medicine
Unable to be detected by conventional technologies, cellular functional
heterogeneity leads to differences in patient response and disease
progression. Filling this gap, IsoPlexis’ single-cell functional proteomics is
allowing researchers to characterize the range of extracellular functions (32+
cytokines) per single cell. By exploring, understanding, and characterizing
cells based on function, researchers can accelerate therapeutic development
by revealing new phenotypes that specifically correlate to individual disease
or response states.
References- J. Rossi et al., “Preinfusion polyfunctional anti-CD19 chimeric antigen receptor T cells
are associated with clinical outcomes in NHL,” Blood, 132(8):804-814, 2018. - Y. Chen et al., “SIRPα expression delineates subsets of intratumoral monocyte/
macrophages with different functional and prognostic impact in follicular lymphoma,”
Blood Cancer J, 9:84, 2019.
IsoPlexis Enables Discovery of New Cell Types
to Accelerate Cancer Immunology
SPONSORED CONTENT
IsoPlexis’ functional extracellular phenotyping is addressing urgent
challenges in cancer immunology.