Requirements for DI Particle Prophylaxis Against Vesicular Stomatitis Virus Infection in vivo

Abstract

In contrast to biologically active DI [defective interfering] particles, neither UV-inactivated standard virus nor either of 2 different homologous UV-inactivated DI particles showed any prophylactic effect when injected intracerebrally into mice concomitantly challenged with VSV. Although UV-inactivated DI particles did not prevent death when given with the challenge virus, they did significantly lengthen the time until death occurred. Also, both UV-inactivated standard virus and DI particles protected mice against late challenge (at 3 or 10 days after treatment). Dosage titrations of preparations of 2 different active DI particles showed significant prophylaxis against simultaneous challenge with numbers of DI particles 10- to 100-fold lower than those which gave no prophylaxis when UV-inactivated. Thus, prophylaxis in this system required biologically active DI particles.