Abstract
Top of pageAbstract Background. Infection with wild-type adeno-associated virus (AAV) is common in humans. However, the biology and molecular epidemiology of AAV infection is poorly understood. Because vectors based on AAV are now being used in human gene transfer trials, a more complete characterization of wild-type AAV infection is needed. To that end, we have surveyed fresh (tonsils) and archived frozen human tissues for the presence of AAV DNA. Methods. Total genomic DNA was isolated from 175 tissue samples: tonsil (n = 101), spleen (n = 21), liver (n = 19), lung (n = 16), muscle (n = 15), and heart (n = 3). Samples were screened by degenerate PCR for the presence of AAV and human adenovirus sequences. AAV sequences were further amplified and cloned for sequence analyses. Results. AAV DNA was detected in 7 of 101 (7%) tonsil samples and 2 of 74 other tissues (1 spleen and 1 lung). Adenovirus sequences were identified in 19 of 101 (19%) tonsils, but not in any other tissues. Two tonsil samples contained both AAV and adenovirus sequences. The amount of AAV DNA in each of the positive tissues was determined by quantitative PCR; levels ranged between 76 – 15,500 AAV copies/microgram of total DNA. Complete capsid sequences were generated from all 9 AAV containing tissues. Sequence analyses showed that 8 of the capsid sequences were AAV-2 like (96 – 98% amino acid identity), while the single spleen isolate was intermediate between genotypes 2 and 3 (91% vs AAV2, 92% vs AAV3). In this particular isolate, the majority of the amino acid substitutions mapped to surface exposed hypervariable domains. Conclusions. Following natural infection, AAV DNA can be easily found in human tissues, especially at the presumed portal of entry (oropharynx). In our cohort, the most common genotype was AAV2. Interestingly, the AAV2 capsid sequences were not identical to the published AAV2 sequence. The finding of AAV DNA outside of the oropharynx suggests that wild-type AAV can and does disseminate during natural infection.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
