# Modulation of Immune responses to gene therapy by Creation of AAV-specific Chimeric antigen receptor regulatory T cells (CAR-Tregs)

> **NIH NIH P01** · UNIV OF MASSACHUSETTS MED SCH WORCESTER · 2021 · $544,375

## Abstract

Project 4 - Abstract
In Project 4, we will use our novel adeno-associated virus (AAV) directed chimeric antigen
receptor (CAR) T-cells and T regulatory cells (Tregs) to modulate and mitigate immune
responses to AAV gene therapy for alpha-1-antitrypsin (AAT) disease. We have shown that our
AAV CARs can clear AAV transduced cells similar to what was observed in the early
Hemophilia trials and our AAV-CAR Tregs are able to allow modulate anti- capsid and anti-
transgene immune responses allowing for stable and persistent transgene expression. We will
optimize our current AAV CAR Treg construct and protocols to make the most suppressive and
functional CAR Tregs. Then we will further characterize the suppressive function of our AAV
CAR T-regs in response to the immunogenic rh32.33 capsid in mouse models. We will further
determine if they are able to overcome pre-existing immunity to capsid which is a large issue for
clinical gene therapy due to the large number of patients who have pre-existing immunity to
AAV. And, we will study if AAV CAR T-regs can overcome pre-existing immunity to transgenes
like those involved in CRISPR genome editing, as again most patients have immune response
to CRISPR proteins causing the likelihood of survival of edited cells to be limited. We will also
determine if AAV CAR T-regs can allow for re-dosing of AAV vectors, allowing for multiple
doses of AAV gene therapy to be delivered to reach optimal therapeutic expression. In addition,
we will further characterize the modulation of the immune system to immunogenic transgenes
by AAV CAR Tregs allowing for stable immunogenic transgene expression. Finally, we will
characterize the immune responses to AAV delivery by in ferrets, a novel model in the AAV field
regarding immune responses. We will investigate how well the ferret model recapitulates the
observations in the clinic and whether capsid specific cytotoxic and/or T-regulatory cells are
generated after systemic or intramuscular injection of ferrets. Overall this project will allow us to
learn considerably about the immune responses generated after AAV gene therapy and allow
us to develop powerful tools to modulate and mitigate immune responses that are relevant for
clinical gene therapy development.

## Key facts

- **NIH application ID:** 10270095
- **Project number:** 1P01HL158506-01
- **Recipient organization:** UNIV OF MASSACHUSETTS MED SCH WORCESTER
- **Principal Investigator:** Allison May Keeler-Klunk
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $544,375
- **Award type:** 1
- **Project period:** 2021-08-09 → 2026-07-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10270095

## Citation

> US National Institutes of Health, RePORTER application 10270095, Modulation of Immune responses to gene therapy by Creation of AAV-specific Chimeric antigen receptor regulatory T cells (CAR-Tregs) (1P01HL158506-01). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10270095. Licensed CC0.

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