Effects of temperature and shear force on infectivity of the baculovirus Autographa californica M nucleopolyhedrovirus

Virus stability and infectivity during stressful conditions was assessed to establish guidelines for future virus filtration experiments and to contribute to the body of knowledge on a widely used virus. A recombinant baculovirus of Autographa californica M nucleopolyhedrovirus (AcMNPV), vHSGFP, was incubated at 15–65 °C. A 2-log decrease in virus infectivity occurred after virus incubation above 45 °C. The activation energy of virus deactivation was circa 108 kJ/mol. Dynamic light scattering revealed an increase in apparent virus particle size from 150 ± 19 to 249 ± 13 nm at 55 °C. Protein and DNA concentrations in solution correlated well with virus aggregation as temperature was increased. Infectivity of vHSGFP stored for 5 months at 4 °C or exposed to shear stress from stirring (100 rpm, 1.02 × 10−5 psi) and pumping (50–250 ml/min, 1.45 × 10−5 to 7.25 × 10−5 psi) did not change with time. Unlike temperature variations, cold storage and shear stress appeared to have little impact on infectivity.