A BAFF ligand-based CAR-T cell targeting three receptors and multiple B cell cancers

Derek P Wong,Bryan J Jones,Reshmi Parameswaran,Anusha Anukanth,Samantha Dunmire,Walker S Lahr,Nand K Roy,Branden S Moriarity,Paolo Caimi,Nicole J Shirkey-Son,Beau R Webber,Keman Zhang,Abhishek Asthana

doi:10.1038/s41467-021-27853-w

Abstract

B cell-activating factor (BAFF) binds the three receptors BAFF-R, BCMA, and TACI, predominantly expressed on mature B cells. Almost all B cell cancers are reported to express at least one of these receptors. Here we develop a BAFF ligand-based chimeric antigen receptor (CAR) and generate BAFF CAR-T cells using a non-viral gene delivery method. We show that BAFF CAR-T cells bind specifically to each of the three BAFF receptors and are effective at killing multiple B cell cancers, including mantle cell lymphoma (MCL), multiple myeloma (MM), and acute lymphoblastic leukemia (ALL), in vitro and in vivo using different xenograft models. Co-culture of BAFF CAR-T cells with these tumor cells results in induction of activation marker CD69, degranulation marker CD107a, and multiple proinflammatory cytokines. In summary, we report a ligand-based BAFF CAR-T capable of binding three different receptors, minimizing the potential for antigen escape in the treatment of B cell cancers.

Highlights

Beyond CD19, 70% of these clinically investigated CAR-T therapies are directed against just 10 antigens, reflecting a significant duplication of targets[19]
We have developed a BAFF ligand-based CAR construct and have successfully delivered it into T cells using a non-viral transposon system
BAFF CAR-T targets BAFF-R, BCMA, and TACI expressed on surface of almost all B cell cancers

Summary

Results

A BAFF ligand-based CAR-T developed using non-viral gene delivery. We designed the BAFF ligand-based CAR construct using intracellular CD28, OX40/CD134 costimulatory domains, and the CD3ζ signaling domain, as well as the CD28 transmembrane domain (Fig. 1a). We utilize a non-viral genetic engineering approach to stably integrate the BAFF-CAR into T cells using the TcB transposon system. A modified pLVX expression vector was used (Supplementary Fig. 1a) Both lentiviral and TcB-based delivery resulted in stable BAFF-CAR expression, as evidenced by the detection of BAFF ligand on the T cell surface via flow cytometry (Fig. 1c). BAFF CAR-T cells produced using the TcB transposon method were assessed for stable expression of BAFF-CAR. BAFF CAR-T cells exhibited significantly higher cytotoxicity than both unmodified and no-BAFF control T cells, while no-BAFF control T cell cytotoxicity was not significantly different from that of unmodified T cells (Fig. 1d) This confirms that our BAFF-CAR construct is functional and that the presence of BAFF at the N-terminus is necessary for cytotoxic function.

Electroporation of TcBuster platform

Discussion

60 Control-T

Methods