Gene Therapy in Action: Adeno-Associated Viral Vectors

Adeno-associated viral vectors, or AAVs, are the tiny shells of viruses. And today they are the most common vessels for delivering gene-based therapies.  In this episode, we’ll launch into the past, present, and future of AAVs. 

Imagine a rocket ship blasting off from Earth with cargo bound for a distant space station, and you have a pretty good idea what adeno-associated viral vectors are all about. But instead of ferrying hardware and supplies, AAVs carry genes.

It’s an achievement nearly six decades in the making. That might seem like a long time to tinker with something smaller than the tiniest single-celled organism. But just like building a rocket ship destined for the deep reaches of space, the development of AAV vectors required patience, persistence, and a few leaps of faith.

In the era before DNA sequencing and gene cloning, scientists in the 1960s realized that adeno-associated viral vectors could be a window into understanding genetic variations in viruses – and eventually other organisms, too.

The fact that AAVs were immunologically distinct from other viruses made them curious things.

So in the 1970s, AAV research took off in three directions. One determined that the simple AAV DNA could be rewritten and edited in a lab. The second found that although these small viruses can infect humans, they don’t replicate without a “helper virus” (such as adenovirus). In the absence of another virus, they remain latent, and appear to be of little threat to human health. The third investigated whether AAVs could become vectors for transferring genes from one organism to another. 

This all culminated in 1978, when the first cloned AAV was generated and was successfully transferred to a cell of the E. coli bacterium, where it produced 50 new colonies of AAVs.

So now we had proof that adeno-associated viruses could be artificially produced, that they

could be hollowed out and filled with other genetic material, and that they could potentially be

a vector for delivering genes without harming their new host.

By the 1980s, we had the capability to build lots of viral rocket ships and fill them with genetic cargo, we just needed a destination to send them. Enter the burgeoning field of gene therapy, with its focus on developing treatments for genetic diseases like cystic fibrosis, hemophilia B, Parkinson’s, and more.

Research has continued and today, adeno-associated viral vectors are a mainstay of gene therapy development. While progress is necessarily slow, gene therapy is a science that is aiming for the stars. And with AAV vectors, they are now within our reach.

For more education on gene therapy, visit www.genetherapynetwork.com.