1. ¹Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
2. ²Department of Pediatric Surgery, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
3. ³Department of Pediatrics, Section of Pediatric Pulmonology at St. Christopher's Hospital for Children, Drexel University College of Medicine, Philadelphia, Pennsylvania 19104, USA
4. ⁴Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
5. ⁵Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
6. ⁶Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
7. ⁷Department of Comparative Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
8. ⁸Department of Pediatrics and Powell Gene Therapy Center, University of Florida, Gainesville, Florida 32611, USA

Correspondence: Anne C. Fischer or William B. Guggino, Johns Hopkins University School of Medicine, WBSB 210, 725 N. Wolfe Street, Baltimore, MD 21205, USA. Fax: (410) 955-0461. E-mail: wguggino@jhmi.edu

Received 15 July 2003; Accepted 20 August 2003.

Abstract

Bronchoscopic microspraying of recombinant adeno-associated viral (rAAV) vectors targets high doses of vector directly to pulmonary epithelium. Single-dose endobronchial gene therapy trials have been accomplished in cystic fibrosis patients; however, repeated dosing strategies are likely essential for lifetime correction. These studies address whether serial redosing with rAAV2 vectors results in an antiserotypic response and, furthermore, whether it triggers an inflammatory response prohibitive to transgene expression. Serial redosing of 9 10¹¹ infectious units of aerosolized rAAV2 vectors to rhesus macaques resulted in successful gene transfer by quantitative PCR (1.43 10⁹ copies/g tissue) and transgene expression. Additionally, confocal microscopy and immunohistochemical analysis demonstrated in situ expression localized to the pulmonary epithelium. Although serial redosing did induce a heightened anti-neutralizing antibody response in sera, gene transfer prevailed with resultant expression. This study is the first to demonstrate successful gene transfer subsequent to repeated aerosolized doses of rAAV2 in immunocompetent nonhuman primates without associated inflammatory responses prohibitive to transgene expression.