Virus removal studies using nanofiltration membranes.

Nanofiltration of immunoglobulin products was investigated as a virus removal step using Planova-controlled pore size membranes. For these studies, purified preparations of an IgG and an IgM were tested with 15 nm and 35 nm Planovace nanofiltration membranes, respectively. The results of spiking studies with four model viruses indicated that both the Planova 15 and 35 membranes removed 6-7 log10 plaque or focus forming units of murine xenotropic retrovirus, simian virus 40 and pseudorabies virus. Although two tandem Planova 35 membranes were tested for clearance of poliovirus, only the Planova 15 membrane removed this virus. Nanofiltration experiments were carried out with protein concentrations up to 12 mg/ml for the IgG and 1-2 mg/ml for the IgM, and protein recovery was excellent.