Practical Mass Cytometry

On measuring photons and ions: Impact on panel design, signal detection and data quality

“Alas poor photon, ion him well.”  

10:30–11:00 am PDT

Presented By: Tim Bushnell, PhD, MBA

Flow cytometry is one of the most powerful single-cell analytical techniques. With the current generation of instruments, 30 or more parameters can be measured simultaneously. In traditional fluorescence flow cytometry, the reporter used is a fluorescent molecule that is measured using a photomultiplier tube or more recently with avalanche photodiodes. With the release of the CyTOF mass cytometer, the reporter used is a metal, and the detection system is a time-of-Flight mass cytometer. When it comes to designing a multidimensional panel, the steps involved for both technologies are similar. Due to specific issues to related measuring photons, there are additional considerations when using fluorescent reporters, adding to the complexity of panel design compared to using metal tags and mass detection. This presentation will discuss the similarities and differences in the panel design process for these two techniques, with an emphasis on how the method of detection of the reporter marker impacts these decisions.

Monitoring immunotherapy with a mass cytometry receptor occupancy assay

11:00–11:30 am PDT

Presented By: Gerd Haga Bringeland, MD, PhD

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system (CNS). Immunotherapy with the monoclonal antibody natalizumab prevents MS disease activity by binding to integrins on circulating leukocytes, thereby blocking leukocytes from entering the CNS. Receptor occupancy is a promising biomarker for monitoring and individualizing natalizumab therapy. I will present a method for accurate measurement of receptor occupancy with high-dimensional mass cytometry and show how I employed the method to study the individual efficacy of immunotherapy with natalizumab in MS patients.

Process development and clinical assessment of CAR T cell products

11:30 am–12:00 pm PDT

Presented By: Greg Hopkins, BS

CAR T cell immunotherapy is a therapeutic approach that involves genetically modifying the patient’s own immune cells ex vivo in order to direct these cells to a tumor target and eliminate tumor cells. bb21217 is a BCMA-directed investigational CAR T cell therapy being developed for the treatment of relapsed or refractory multiple myeloma. bb21217 is manufactured using a PI3K inhibitor (bb007), which is intended to increase in vivo persistence of CAR+ T cells. The safety and efficacy of bb21217 is being explored in the phase 1 CRB-402 study. Here we report the methodology for mass cytometry analyses used to identify key phenotypic features associated with bb2117 CAR+ T cells. CyTOF® uncovered key memory- and effector-associated markers and identified memory-like T cell populations in BCMA-directed CAR+ T cells manufactured in the presence of bb007. CyTOF and unsupervised clustering analysis are powerful tools to understand the biology of cellular products and potentially identify biomarkers associated with clinical outcomes in CAR T-treated patients.