FAQs

  • IsoTag™ is a single chain protein reagent that is delivered in a concentrated stock solution, similar to other protein reagents.

  • Affinity liquid phase separation (ALPS) is the term for the end-user downstream process. There are two variants of the process:

    • Affinity liquid phase separation via tangential flow filtration (ALPS-TFF)

    • Affinity liquid phase separation via centrifugation (ALPS-CF)

  • Yes. We have validated ELISA kits available (by Cygnus Technologies).

    IsoTag™ AAV ELISA Kit

    IsoTag™ LV ELISA Kit

    Residuals of IsoTag™ are <200 ng/E13 vgs in the elution buffer, as determined by beta kits.

  • IsoTag™ transition can be initiated with as little as a 0.1M change in salt concentration, but we typically recommend a 0.5M change to ensure a consistent and robust droplet formation.

  • For AAV - approximately 6mL - 7mL of formulated IsoTag™ is required per liter of harvest, using the ALPS-TFF process.

    For LV - approximately 36mL - 37mL of formulated IsoTag™ is required per liter of harvest, using the ALPS-TFF process.

  • In our benchmarking studies, we have typically seen similar or improved (>20%) recoveries from the IsoTag™ ALPS process compared to an industry standard chromatography process.

  • The ALPS-TFF process is highly effective at washing and concentrating product because of the large pore size of the filter (typically 0.2 um and 0.65 um). To enact a consistent filtration process with these open filters we recommend running at a constant flux using permeate flow control mode.

  • We expect zero toxicity of any IsoTag™ product. We have not seen any cytotoxicity of IsoTag™ in cell culture and we have injected small animal models with viral preps that contain residual amounts of IsoTag™ to no detriment. Analogous reagents have been used in human clinical trials at doses far exceeding residual quantities.

    View our non-GLP toxicology studies for IsoTag™ AAV & LV on our Resources page.

  • The IsoTag™ ALPS-CF and ALPS-TFF process is highly scalable because of the mechanism of the droplet formation - the droplets form the same size regardless of volume so whether you are trying to process 100 mL or 1000L, the droplet formation and concentration dynamics are the same.

  • In our development history of adenovirus, adeno-associated viruses and lentivirus, we have seen zero evidence of reduced viral potency that can be attributed to our purification process.

  • Low speed centrifugation and tangential flow filtration processes.

  • Our volume-based process is compatible with serum and serum free feed streams.

    Specifically, IsoTag™ AAV reagent is compatible with multiple serotypes (1,2,6,8,9,rh10 and PHP.B) and IsoTag™ LV reagent is compatible with any VSV-G pseudotyped vector.