I am trying to extract DNA from a poxvirus in a vaccine containing aluminum hydroxide gel. I wish to purify the virus by removing it from the aluminum hydroxide gel matrix, as the gel, or a component of it, seems to be contaminating my DNA purification (260/280 spectrophotometer reading).
I have tried to centrifuge at a lower G initially to remove the gel, but the virus appears to be embedded in the gel.
I would be very grateful if someone could suggest a way to purify the viral particles from the aluminum hydroxide gel matrix.
The only method I have seen in passing is from the book Vaccine Adjuvants: Preparation Methods and Research Protocols, edited by Derek T. O'Hagan p. 76, with extra hyphens inserted from copy-paste:
"3.5.3. Dissolution of Gels to Release Antigens
Aluminum adjuvant gels are often dissolved to release antigens into solu- tion or antigens are desorbed from the gels for direct measurement of antigens adsorbed onto the gels. This is also done to establish identity of the product, which is one of the tests performed on final products as per the requirements of the regulatory agencies. Antigens can be desorbed by exposing the adsorbed preparations to high salt or phosphate concentrations and/or pH that does not support adsorption. The most commonly used procedure in the vaccine indus- try is to dissolve the gels with 5–10% sodium citrate solution (24). This proce- dure (described below) works well with aluminum phosphate gel and dissolves the gel at 37°C within 24 h, but aluminum hydroxide gel is sometimes difficult to dissolve and requires incubation of vaccine preparations at 37°C for 2–3 d.
Add 100 mg/mL (10% final concentration) of sodium citrate, granular (C6H5Na3O7.2H2O) directly to adsorbed preparation in a glass or plastic tube. A 20% solution of sodium citrate in distilled water may also be used to achieve 5–10% final concentration.
Mix the solution until all the sodium citrate granules have dissolved.
Incubate the tube at 37°C overnight or until clear. With some preparations, the
solution remains cloudy, but the toxoid is completely dissolved. "
Citation (24): World Health Organization (1977) Manual for the Production and Control of Vaccines—Tetanus Toxoid, BLG/UNDP/77.2 Rev.1.
Good luck with that. I might include a sample with 1 - 10 mM EDTA since the preparation will be at 37 for so long, but if the poxvirus is inactivated with formalin then in might be somewhat stable.
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