Biology subjects

Maynard, L. H.

Publications and source records attributed to Maynard, L. H..

2 recordsLinked to original sources

bioRxiv2025

Pooled CAR-T screening in nonhuman primates identifies designs with enhanced proliferation, trafficking, and persistence

Chimeric antigen receptor T (CAR-T) cell therapy has revolutionized treatment for B-cell malignancies, yet over 60% of patients relapse within one year, often due to insufficient CAR-T persistence. While 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 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. Following ex vivo characterization, we administered pooled autologous CAR-T arrays to three NHPs and tracked CAR abundance longitudinally using a novel digital droplet PCR 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 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 endpoint, 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 cell activity. Key pointsO_LIWe developed the first pooled CAR-T screening platform in an immunocompetent nonhuman primate model to directly compare CAR designs. C_LIO_LIWe identified MyD88-CD40 costimulatory domain as vastly superior to conventional domains in proliferation, trafficking and persistence. C_LI

immunology↗

bioRxiv2019

Methods Matter -- Standard Production Platforms For Recombinant AAV Can Produce Chemically And Functionally Distinct Vectors

Different manufacturing approaches have been used in the production of recombinant adeno-associated virus (rAAV). The two leading approaches are transiently transfected human HEK293 cells and live baculovirus infection of Sf9 insect cells. Unexplained differences in vector performance have been seen clinically and preclinically. Thus, we performed for the first time a highly controlled comparative production analysis varying only the host cell species but keeping all other rAAV production parameters the same. We demonstrate that host cell species is critical for determining vector potency. Given these key findings, we then sought to deeply characterize differences in rAAVs when produced by these two manufacturing platforms with multiple analytical approaches including: proteomic profiling by mass spectrometry, isoelectric focusing, cryo-EM, denaturation assays, genomic and epigenomic sequencing of packaged genomes, human cytokine profiling, and comparative functional transduction assessments in vitro and in vivo, including in humanized liver mice. Using these tools weve made two major discoveries: 1) rAAV capsids have post-translational modifications (PTMs) including glycosylation, acetylation, phosphorylation, methylation and deamidation, and these PTMs differ between platforms; 2) rAAV genomes are methylated during production, and these methylation marks are also differentially deposited between platforms. In addition, our data also demonstrate that host cell protein impurities differ between platforms and can have their own PTMs including potentially immunogenic N-linked glycans. We show that human-produced rAAVs are more potent than baculovirus-Sf9 vectors in various cell types in vitro (P < 0.05-0.0001), in various mouse tissues in vivo (P < 0.03-0.0001), and in human liver in vivo (P < 0.005). Collectively, our findings were reproducible across vendors, including commercial manufacturers, academic core facilities, and individual laboratory preparations. These vector differences may have clinical implications for rAAV receptor binding, trafficking, expression kinetics, expression durability, vector immunogenicity as well as cost considerations.

molecular biology↗