Morphological comparison of rabies viral particles before and after rejuvenation in suckling mice and morphogenesis of the rejuvenated virus in cells

Abstract:

[Objective] To observe the morphological recovery of rabies virus strain SRV 9 after rejuvenation in suckling mice and to study its morphogenesis in BHK-21 cells. [Methods] The long freeze-preserved rabies virus strain SRV 9 was rejuvenated through intracerebral inoculation of sucking mice twice, followed by propagation in BHK-21 cells. After cell culture the virus was purified through sucrose gradient density ultracentrifugation. [Results] Electromicroscopy of the purified virus showed that effective recovery of viral shape was obtained after the rejuvenation with majority of viral particles having a typical bullet-like shape and intact spikes on viral membrane. The proportion of DI particles (with short triangle and irregular shapes) in rejuvenatd virus super-natant was significantly decreased compared to un-rejuvenated virus. Viral morphogenesis in cells showed that typical virus parti-cles could form in intracytoplasm 24 hours p.i. and the number of matured viral particles in cytoplasm increased significantly as culture was prolonged from 24 hours to 96 hours p.i.. Furthermore, the rejuvenated virus was observed budding from vacuole membrane in different patterns. [Conclusion] (1) The proportion of DI particles can be significantly decreased by rejuvenated through intracerebral inoculation of sucking mice.(2) The optimal harvest opportunity of SRV9 is after being 1~2 undiluted pas-saged. (3) This research provided more information about morphogenesis of rabies virus.