Acid Adjusted Swine Serum

1. The before or morning of: adjust the pH of the swine serum to between 4.3 and 4.5 with 1N HCl.

2. Place serum for at least 1 hour at 4°C (overnight is best).

3. Centrifuge serum at 6,000 rpm (Beckman centrifuge, 250 ml bottles) for 15 min.

4. Pull off serum by aspiration (peelet is soft and will not stick to bottle).

5. Filter serum successively through 1.2 µm, .85µm and .65 µm filters using 142 mm filter holder.

6. Adjust pH to 7.0 using 1N NaOH.

7. Heat inactivate by bringing to 56°C for 30 min.

8. Serum can be used immediately or stored at -20°C (serum is not sterile at this point!). Do not store at 4°C unless filter sterilzed.