Scientists from Japan have developed a new technique for assessing whether adeno-associated virus (AAV) capsids are full or empty of their therapeutic DNA payload. The team hopes the research will help gene therapy manufacturers improve the effectiveness and quality of their products by early detection of the capsids that are empty of drug product.
According to Susumu Uchiyama, PhD, a professor of biotechnology at Osaka University, “People commonly try to reduce the population of empty capsids using chromatography and/or also centrifugation, but these have technical challenges. Instead, we’ve developed a method that quantifies full and empty capsids directly without any purification.”
Empty capsids in gene therapies are regarded as impurity, as they increase the risk of a patient’s immune reactions to the viral load without providing any therapeutic benefit.
Instead of AAV purification from culture medium or lysed cell mixture for analysis, as Uchiyama explains, the new technique observes AAV full and empty without purification using a mass photometer from Refeyn, an equipment manufacturer based in Oxford, UK. The instrument works by measuring how light is scattered when particles bind to a glass surface.
“We collect a tiny sample at the bioreactor, or culture flask, stage,” he says. “It’s part of the upstream process and much quicker than going through the entire process. We can also monitor the time course of full and empty changes.”
In gene therapies, contaminant proteins often bind permanently to the surface, but the team found that AAVs tend to repeatedly unbind and rebind over time. They were able to use the unbinding signal to quantify how many capsids were full versus empty.
The researchers now plan to incorporate their new tool into a drug development program, leading to early clinical trials.
“We originally developed this process for efficient production of AAV particles,” notes Uchiyama. “Once we’ve developed our process, we’ll pass it onto a CDMO.”
Uchiyama, who has a paper in process at the journal Analytical Chemistry, also delivered a presentation on his technique at Bioprocessing Summit Europe in March.
The post New Upstream Method for Viral Capsid Analysis Using Mass Photometry appeared first on GEN - Genetic Engineering and Biotechnology News.
According to Susumu Uchiyama, PhD, a professor of biotechnology at Osaka University, “People commonly try to reduce the population of empty capsids using chromatography and/or also centrifugation, but these have technical challenges. Instead, we’ve developed a method that quantifies full and empty capsids directly without any purification.”
Empty capsids in gene therapies are regarded as impurity, as they increase the risk of a patient’s immune reactions to the viral load without providing any therapeutic benefit.
Mass photometry
Instead of AAV purification from culture medium or lysed cell mixture for analysis, as Uchiyama explains, the new technique observes AAV full and empty without purification using a mass photometer from Refeyn, an equipment manufacturer based in Oxford, UK. The instrument works by measuring how light is scattered when particles bind to a glass surface.
“We collect a tiny sample at the bioreactor, or culture flask, stage,” he says. “It’s part of the upstream process and much quicker than going through the entire process. We can also monitor the time course of full and empty changes.”
In gene therapies, contaminant proteins often bind permanently to the surface, but the team found that AAVs tend to repeatedly unbind and rebind over time. They were able to use the unbinding signal to quantify how many capsids were full versus empty.
The researchers now plan to incorporate their new tool into a drug development program, leading to early clinical trials.
“We originally developed this process for efficient production of AAV particles,” notes Uchiyama. “Once we’ve developed our process, we’ll pass it onto a CDMO.”
Uchiyama, who has a paper in process at the journal Analytical Chemistry, also delivered a presentation on his technique at Bioprocessing Summit Europe in March.
The post New Upstream Method for Viral Capsid Analysis Using Mass Photometry appeared first on GEN - Genetic Engineering and Biotechnology News.