VirusTech News and Updates

We have recently purchased the newest model from the Optima X Series, the Optima XE-90, and several rotors to fit different volumens and sample amount. Thus, the core will ensure the rapid and effective production, purification and concentration of our virus sortiment. This Ultracentrifuge will also allow us to increase volumes and/or number of samples that may be processed at a given time and speeding up the delivery or our services.

Updates

New services available from the core

• Check out the new publication list in our website. The core is happy to announce its contribution to some of the research work made in KI. We work everyday to help you and your research to move forward.

• No reporter --> No problem.

We have developed a lenti/retroviral titration method measuring transducing units, or number of proviral copies in the infected cells. If your transgene has no reporter the only available option for you to titer your viruses was by analysing the number of RNA copies (physical titration). This method usually overestimates the actual number functional viral particles in a 100-150 fold (Geraerts et al., 2006 and based in our own analyses), when compared to functional titration or expression of reporter genes in the infected cells upon FACS analysis. Therefore, we offer a new titration method based in the integration of the provirus by analysing the number of copies of provirus integrated in the transduced cells and normalizing to a house keeping gene. In our hands the values obtained by this method compared to the FACS functional methods were comparable, thus presenting a viable titration method when no reporter is present in the trangene.

Purification and concentration of viruses: We used precipitation/concentration and ultracentrifugation to ensure an almost 99,6% of purificed viruses in our products. We offer several services of virus media concentration depending on the necessities of our customers:

• 100 KDa Centricon Plus-70 Centrifugal Filter: This is our standard method to concentrate supernatants. Pros: the concentrated product is ready to use, fast and reliable. Cons: Limited virus media volumen per prep.
• PEG precipitation: An alternative method of virus precipitation. Pros: Higher volumes of viral supernatant per prep, PEG reduces the inmunoresponse when viral vectors are applied in vivo, viruses titer lost upon thawing and freezing cycles is dramatically reduced (25% of titer lost reported against a 3% in our experiments). Cons: PEG precipitates other impurities, so ultracentrifugation is needed as a further purification step.

New family of AAVs come to stay at the VirusTech Core

The facility has recently acquired the plasmids necessary for the production of the new variations of the AAV9 pseudotype viruses. These viruses designated AAV-PHP.eB and AAV-PHP.S are powerful tools that allow the users to label the different cell types in the central or the peripheral  nervous system respectively, avoiding invasive methods like direct injection in the nervous system. These new viruses can be produced at really high titers which brings the possibility of systemic injections via IP and yet retain the specificity for the Nervous system cells (Chan et al., 2017; Deverman et al., 2016).

Check our AAV page to find out more.