Human Treg responses allow sustained recombinant adeno-associated virus–mediated transgene expression

• Published in: The Journal of clinical investigation Vol. 123; no. 12; pp. 5310 - 5318
• Main Authors: Mueller, Christian, Chulay, Jeffrey D., Trapnell, Bruce C., Humphries, Margaret, Carey, Brenna, Sandhaus, Robert A., McElvaney, Noel G., Messina, Louis, Tang, Qiushi, Rouhani, Farshid N., Campbell-Thompson, Martha, Fu, Ann Dongtao, Yachnis, Anthony, Knop, David R., Ye, Guo-jie, Brantly, Mark, Calcedo, Roberto, Somanathan, Suryanarayan, Richman, Lee P., Vonderheide, Robert H., Hulme, Maigan A., Brusko, Todd M., Wilson, James M., Flotte, Terence R.
• Format: Journal Article
• Language: English
• Published: United States American Society for Clinical Investigation 01.12.2013
• Subjects: Adeno-associated virus; alpha 1-Antitrypsin - biosynthesis; alpha 1-Antitrypsin - genetics; alpha 1-Antitrypsin - immunology; alpha 1-Antitrypsin Deficiency - therapy; Biomedical research; Biopsy; Capsid - immunology; Clinical trials; Clone Cells - chemistry; Deoxyribonucleic acid; Dependovirus - genetics; Dependovirus - immunology; DNA; Drug dosages; Gene Expression Regulation - immunology; Gene Rearrangement, beta-Chain T-Cell Antigen Receptor; Genetic Therapy; Genetic Vectors - immunology; Genetic Vectors - therapeutic use; Humans; Injections, Intramuscular; Lymphocyte Activation; Lymphocytes; Muscle, Skeletal - chemistry; Muscle, Skeletal - immunology; Muscle, Skeletal - pathology; Muscle, Skeletal - virology; Receptors, Antigen, T-Cell, alpha-beta - genetics; Recombinant Fusion Proteins - biosynthesis; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - immunology; Rodents; Studies; T-Lymphocytes, Regulatory - immunology; Transgenes - immunology
• ISSN: 0021-9738; 1558-8238; 1558-8238
• DOI: 10.1172/JCI70314

Recombinant adeno-associated virus (rAAV) vectors have shown promise for the treatment of several diseases; however, immune-mediated elimination of transduced cells has been suggested to limit and account for a loss of efficacy. To determine whether rAAV vector expression can persist long term, we administered rAAV vectors expressing normal, M-type α-1 antitrypsin (M-AAT) to AAT-deficient subjects at various doses by multiple i.m. injections. M-specific AAT expression was observed in all subjects in a dose-dependent manner and was sustained for more than 1 year in the absence of immune suppression. Muscle biopsies at 1 year had sustained AAT expression and a reduction of inflammatory cells compared with 3 month biopsies. Deep sequencing of the TCR Vβ region from muscle biopsies demonstrated a limited number of T cell clones that emerged at 3 months after vector administration and persisted for 1 year. In situ immunophenotyping revealed a substantial Treg population in muscle biopsy samples containing AAT-expressing myofibers. Approximately 10% of all T cells in muscle were natural Tregs, which were activated in response to AAV capsid. These results suggest that i.m. delivery of rAAV type 1-AAT (rAAV1-AAT) induces a T regulatory response that allows ongoing transgene expression and indicates that immunomodulatory treatments may not be necessary for rAAV-mediated gene therapy.