AAV5

AAV5 refers to adeno-associated virus serotype 5, one of several naturally occurring serotypes used as a gene delivery vector. Like other AAVs, AAV5 is a small, non-enveloped, single-stranded DNA virus in the Dependoparvovirus genus. It is replication-defective in the absence of a helper virus (such as adenovirus or herpesvirus) and is typically used in research and therapeutic contexts by providing the necessary transgene cassette inside the viral genome.

The AAV5 genome is flanked by inverted terminal repeats and can accommodate a transgene of about 4.7 kilobases along with regulatory elements such as promoters and polyadenylation signals. Production relies on helper plasmids or helper systems to supply replication and packaging functions, and vector genomes are typically packaged within AAV5 capsids. Delivery vectors are commonly produced using established systems in mammalian cells or insect cell platforms.

Tissue tropism and serology for AAV5 are influenced by the capsid proteins, which interact with cell surface glycans and other receptors to determine which tissues are efficiently transduced. AAV5 is noted in some studies for relatively efficient transduction in certain tissues such as the lung, liver, and central nervous system in preclinical models, though outcomes vary by species, dose, and promoter choice. Pre-existing neutralizing antibodies against AAV5 occur in humans but generally at different frequencies than for AAV2, affecting clinical performance in some populations.

In clinical and preclinical contexts, AAV5 is explored for ocular, pulmonary, CNS, and liver-directed gene therapy applications. As with other AAV vectors, safety considerations include primarily episomal transgene expression, low-level risk of integration, and potential immune responses to capsid or transgene.