An evaluation of purification methods for baculoviruses

Abstract

Procedures for the purification of virus particles and nucleocapsids of granulosis and nuclear polyhedrosis virus particles are described. Optimal recovery of virus particles occurred when inclusion bodies at 25 mg/ml were “dissolved” at a concentration of 0.05 M sodium carbonate at 30°C for 30 min to 1 hr. The dissolution mixture was diluted 10-fold with distilled water, and virus particles were sedimented at 50,000 g for 1 hr, resuspended in distilled water, and purified on 25 to 60% w/w sucrose gradients in distilled water. Purified virus particles were stored at 4°C in 0.005 M sodium carbonate. Nucleocapsids were released from enveloped virus particles by treatment with 0.2% Nonidet P-40 for 30 min, and subsequently purified on 25 to 60% w/w sucrose gradients. These procedures should provide the basis for a critical comparison of the biophysical and immunogenic properties of baculoviruses isolated from different insect species.