The removal of viruses during the purification of equine antisera using filtration aids Hyflo Super-Cel and Fulmon Super A.

The manufacturing process in Australia for equine antisera against various venoms/toxins is based primarily on ammonium sulphate precipitation of pepsin-digested IgG, whereby Fc and F(ab')(2)fragments are separated. The capacity of the process to remove non-enveloped and enveloped model viruses was assessed using a scaled-down process. Each virus was added to mid-process samples from equine plasma before the material was applied to Hyflo Super-Celtrade mark filtration followed by Fulmonttrade mark Super A filtration. Samples were analysed pre- and post-filtration and the log clearance of the viruses calculated. The mean clearance factors for viral load of canine adenovirus type II (CAV(2)), poliovirus type 1 (PV1), infectious bovine rhinotracheitis virus (IBR) and canine distemper virus (CDV) were 5.3 logs, 4.2 logs, 5.7 logs and 4. 0 logs respectively. Clearance results as virus is adsorbed to the filtration aids which are removed from the process, thereby demonstrating improved viral safety of equine antisera produced by CSL.