Rapid In Vitro Cytotoxicity Evaluation of Jurkat Expressing Chimeric Antigen Receptor using Fluorescent Imaging

Summary

A protocol to evaluate quantitative tumor cell killing by Jurkat cells expressing chimeric antigen receptor (CAR) targeting single tumor antigen. This protocol can be used as a screening platform for rapid optimization of CAR hinge constructs prior to confirmation in peripheral blood-derived T cells.

Abstract

Chimeric antigen receptor (CAR) T cells are at the forefront of oncology. A CAR is constructed of a targeting domain (usually a single chain variable fragment, scFv), with an accompanying intra-chain linker, followed by a hinge, transmembrane, and costimulatory domain. Modification of the intra-chain linker and hinge domain can have a significant effect on CAR-mediated killing. Considering the many different options for each part of a CAR construct, there are large numbers of permutations. Making CAR-T cells is a time-consuming and expensive process, and making and testing many constructs is a heavy time and material investment. This protocol describes a platform to rapidly evaluate hinge-optimized CAR constructs in Jurkat cells (CAR-J). Jurkat cells are an immortalized T cell line with high lentivirus uptake, allowing for efficient CAR transduction. Here, we present a platform to rapidly evaluate CAR-J using a fluorescent imager, followed by confirmation of cytolysis in PBMC-derived T cells.

Introduction

CAR-T cell therapy has shown great promise in hematological malignancies, evident from the 6 FDA-approved CAR-T products since 2017, as reported by the National Cancer Institute¹. There are numerous CAR-T cells in clinical trials for targeting solid tumors. Engineering novel CAR targets and optimizing the CAR construct is vital to the efficacy of a CAR-T cell. Choosing the ideal CAR construct for each application is essential for accurate targeting of tumor associated antigens (TAA) while avoiding low levels of TAA expression in normal tissues².

A CAR construct is primarily made of five compar....

Protocol

NOTE: All cell culture work is done in a biosafety cabinet with a lab coat, gloves, and following standard aseptic techniques.

1. Generating CAR expressing Jurkats (CAR-J)

1. Purchase Jurkat cells, clone E6-1 from ATCC. Thaw 1 x 10⁶ cells in a T-75 flask and culture them in T-75 flasks. Maintain them in suspension at 0.6 x 10⁶ cells per mL using Roswell Park Memorial Institute (RPMI) media supplemented with 10% FBS in an incubator at 37 °C with 5% CO₂.
2. Plate 1 x 10⁵ Jurkat cells per well of a tissue culture treated 24 well plate in 500 µL of RPMI growt....

Discussion

Here we have proposed a rapid method to efficiently evaluate the target-specific cytolytic activity induced by CAR expression in Jurkat cells. All CAR constructs have the same scFv but different hinge and transmembrane domains which have been shown to affect CAR-T cells potency¹³. Further evaluation of non-specific killing by these CAR-J was done by culturing them with antigen knock out (KO) cells. This demonstrates that the killing is tumor antigen specific and not due to basal activation by the .......

Materials

Name	Company	Catalog Number	Comments
15 mL Conical Tube (Sterile)	Midwest Scientific	#C15B	Any similar will work
50 mL Conical Tube (Sterile)	Thermo Scientific	339652	Any similar will work
Black/Clear 96 well plate	Falcon	353219	Celligo has a list of compatible plates
Celigo 4 Channel Imaging Cytomenter	Nexcelcom Bioscience	200-BFFL-5C	Any similar will work
Celigo Software	Nexcelcom Bioscience	Version 5.3.0.0	Any similar will work
Cell Culture Incubator	Thermo Scientific	HeraCell 160i	Any similar will work
Cell Culture Treated Flasks (T75, various sizes, Sterile)	TPP	90076	Any similar will work
CFSE	Tonbo	13-0850-U500	Any similar will work
Cytek Muse Cell Analyzer	Cytek	0500-3115	Any similar will work
DMEM	Gibco	11995-040	Any similar will work
FBS	Gemini bio-products	900-108	Any similar will work
Flow Cytometer	Cytek, BD, etc	Aurora, LSR II, etc	Any similar will work
FlowJo Sortware	Becton Dickinson & Company	Version 10.7.1	Any similar will work
Fluorobrite DMEM	Gibco	A18967-01	Any similar will work
GraphPad Software	GraphPad	Version 9.3.1 (471)	Any similar will work
Multichanel Pipette	Thermo Scientific	Finnpipette F2	Any similar will work
PBS	Gibco	10010-031	Any similar will work
PenStrep	Gibco	15070-063	Any similar will work
Pipette tips (Sterile, filtered, 1 mL, Various sizes)	Pr1ma	PR-1250RK-FL, etc	Any similar will work
Pipettors	Thermo Scientific	Finnpipette F2	Any similar will work
Propidium Iodide	Invitrogen	P1304MP	Any similar will work
RPMI	Corning	10-041-cv	Any similar will work
Serological Pipette Aid	Drummond Scientific	4-000-105	Any similar will work
Serological Pipettes (Sterile, various sizes)	Pr1ma	PR-SERO-25, etc	Any similar will work
Sodium Pyruvate	Corning	25-000-CI	Any similar will work
Sterile Reservoirs	Midwest Scientific	RESE-2000	Any similar will work
Table top centrifuge	Eppendorf	5810R	Any similar will work