Evaluation of viral contamination in a baculovirus expression system.

Insect expression systems based on baculovirus are widely used for generating recombinant proteins. Here, the infectivity of baculoviruses under the physiological stresses of 'freeze-thaw' and sonication and the baculoviral contamination of recombinant proteins after protein purification were evaluated. Our findings suggest that Nonidet P-40 (NP-40) treatment of baculoviruses completely abolishes their infectivity and that recombinant proteins purified with affinity beads do not include infectious baculoviruses. We therefore suggest that baculovirus is completely inactivated by NP-40 treatment and that recombinant proteins are unlikely to be contaminated with infectious baculoviruses after their affinity purification.