# Tolerization of dystrophin and adeno-associated virus immunity

> **NIH NIH R21** · UNIVERSITY OF CALIFORNIA-IRVINE · 2020 · $431,375

## Abstract

Project Summary/Abstract.
Adeno-associated virus (AAV) micro-dystrophin (µdys) gene therapy shows great promise to cure Duchenne
muscular dystrophy (DMD). Recent studies have shown that DMD patients have a pre-existing immunity or
develop immunity against the AAV-µdys gene therapy after administration. Although early trial data indicate that
systemic gene therapy leads to widespread expression of µdystrophin in muscle, the long-term consequence of
AAV and dystrophin immunity on the efficacy and stability of gene therapy in not known. Our long-term goal is
to determine the role of immunity in AAV-µdys gene therapy and define the regulatory mechanisms constraining
these immune responses. These discoveries will determine if AAV- and dystrophin-specific immune responses
impede on the success of gene therapy and will facilitate the design of potential therapies that mitigate these
responses. The objective of the current study is to specifically define whether AAV capsid- and dystrophin-
specific T cells limit the efficacy and stability of AAV µdys gene therapy, and determine if regulatory T cells
(Tregs) mitigate these immune responses in the mdx mouse model of Duchenne muscular dystrophy (DMD).
We will test the central hypothesis that Tregs suppress AAV- and dystrophin-specific T cells, which we predict
limit the efficiency of myofiber transduction and immunologically ‘attack’ µdystrophin+ myofibers. The premise for
the proposed studies is supported by several reported lines of evidence, including that 50% of DMD patients
harbor dystrophin-specific T cells, humans develop AAV-specific immunity (humeral and cellular) upon exposure,
and Tregs are elevated in dystrophic muscle and suppress antigen-specific T cells. Our hypothesis will be tested
by addressing two specific aims: (aim 1) determine the function of AAV- and dystrophin-specific T cells, and (aim
2) determine whether Tregs suppress AAV- and dystrophin-specific T cells. Our proposed study is significant as
it will define the functional role of immunity in AAV-µdys gene therapy and provide critical insight that will
positively impact the design of future gene therapy trials in DMD. The proposed research is also innovative
because we will investigate the capacity of Tregs to suppress AAV and dystrophin immunity, a previously-
unexamined process. Moreover, we will test the capacity of a humanized IL-2/anti-IL-2 antibody complex (hIL-
2c) to expand Tregs in vivo, and determine its effect on suppressing immunity and the efficacy of AAV µdys gene
therapy. Insight into Treg-mediated control of AAV- and dystrophin-specific T cells is impactful as it may be
leveraged as a unique therapeutic avenue to inhibit AAV- and dystrophin-specific T cells and induce long-term
tolerance to AAV or dystrophin.

## Key facts

- **NIH application ID:** 9876887
- **Project number:** 1R21NS114918-01
- **Recipient organization:** UNIVERSITY OF CALIFORNIA-IRVINE
- **Principal Investigator:** Sergio Armando Villalta
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $431,375
- **Award type:** 1
- **Project period:** 2020-04-01 → 2023-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9876887

## Citation

> US National Institutes of Health, RePORTER application 9876887, Tolerization of dystrophin and adeno-associated virus immunity (1R21NS114918-01). Retrieved via AI Analytics 2026-06-12 from https://api.ai-analytics.org/grant/nih/9876887. Licensed CC0.

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