Inventors:
James W. Bloom - Richmond CA
Melvin F. Wong - San Francisco CA
Gautam Mitra - Kensington CA
International Classification:
C07K 322, C07K 1528, C07K 1500
Abstract:
Antibody preparation purified using immobilized protein A and yet substantially free of protein A that may have solubilized during the purificaiton process. The antibodies include less than 15 ng protein A per mg of antibody, preferably less than 1 ng/mg. Low protein A content is obtained by first contacting the antibodies and solubilized protein A with an ion exchange resin under conditions to adsorb both. The antibodies and protein A are then sequentially eluted under conditions of increasing ionic strength.