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Updated: Sep 11, 2025
Manufacturing Chimeric Antigen Receptor CAR T Cells for Adoptive Immunotherapy
Published on: December 17, 2019
Pooled CAR-T screening in pig-tailed macaques identifies designs with enhanced proliferation, trafficking, and
Lucy H Maynard1,2, Eric J Cavanaugh1, Haiying Zhu3
1Translational Science and Therapeutics Division, Fred Hutchinson Cancer Center, Seattle, WA.
Abstract:
Chimeric antigen receptor T-cell (CAR-T) therapy has revolutionized the treatment of B-cell malignancies; however, >60% of patients relapse within 1 year, often due to insufficient CAR-T persistence. Although mouse and primary cell models have been instrumental in advancing CAR-T therapy, they frequently fail to predict clinical outcomes, underscoring the need for more translationally relevant models. To address this limitation, we conducted, to our knowledge, the first systematic evaluation of CAR structure-function relationships in an immunocompetent nonhuman primate (NHP) model. We engineered an array of 20 CD20-targeted CARs with distinct combinations of hinge, transmembrane, and costimulatory domains. After ex vivo characterization, we administered pooled autologous CAR-T arrays to 3 NHPs and tracked CAR abundance longitudinally using a novel digital droplet polymerase chain reaction assay. Ex vivo, CAR-T cells incorporating the MyD88-CD40 costimulatory domain exhibited markedly distinct functional profiles, including increased activation, unique cytokine secretion, tonic signaling, and resistance to exhaustion. In vivo, MyD88-CD40 CARs expanded dramatically, comprising up to 100% of peripheral CAR-T cells and significantly outperforming canonical CD28- and 4-1BB-based CARs. This expansion was associated with robust B-cell depletion across all animals. MyD88-CD40 CARs, particularly those with a CD28 hinge and transmembrane domain, demonstrated superior trafficking to secondary lymphoid tissues and persistence through study end point, unlike other CARs, which waned by day 28. Our findings highlight the value of NHP models for screening CAR designs and identify MyD88-CD40 CARs as candidates with unmatched potency. The unique functional attributes conferred by this domain may provide key insights into features that drive enhanced CAR-T activity.
Insights
New chimeric antigen receptor T (CAR-T) cell designs using the MyD88-CD40 costimulatory domain show superior persistence and potency in nonhuman primates, addressing CAR-T therapy relapse. This advance offers hope for more effective B-cell malignancy treatments.
Area of Science:
- Immunology
- Cell Therapy
- Oncology
Background:
- Chimeric antigen receptor T (CAR-T) cell therapy shows promise for B-cell malignancies but suffers from high relapse rates due to poor CAR-T cell persistence.
- Current preclinical models often fail to predict clinical CAR-T cell efficacy, necessitating more translationally relevant models.
Purpose of the Study:
- To systematically evaluate CAR structure-function relationships in an immunocompetent nonhuman primate (NHP) model.
- To identify novel CAR designs with improved persistence and anti-tumor activity for B-cell malignancies.
Main Methods:
- Engineered 20 CD20-targeted CARs with varying hinge, transmembrane, and costimulatory domains.
- Administered pooled CAR-T cell arrays to NHPs and monitored CAR abundance using digital droplet PCR.
- Assessed CAR-T cell function ex vivo and in vivo, including expansion, cytokine secretion, and tissue trafficking.
Main Results:
- CAR-T cells with the MyD88-CD40 costimulatory domain exhibited enhanced activation, unique cytokine profiles, and resistance to exhaustion ex vivo.
- In vivo, MyD88-CD40 CARs demonstrated dramatic expansion, outperforming CD28- and 4-1BB-based CARs, and achieved robust B-cell depletion.
- MyD88-CD40 CARs, especially with CD28 hinge/transmembrane domains, showed superior lymphoid tissue trafficking and prolonged persistence compared to other CAR designs.
Conclusions:
- NHP models are valuable for screening CAR designs and optimizing CAR-T cell therapy.
- MyD88-CD40 CARs represent a potent new class of CARs with enhanced functional attributes and superior in vivo performance.
- These findings offer critical insights into CAR features that drive improved CAR-T cell activity and may overcome clinical relapse challenges.
