| Rabies, induced by rabies virus, mainly induced encephalomyelitis, is a kind ofneuroinvasive infectious disease. The virus invaded the host by bruised skin ormucosa, after that rabies virus enter the central nervous system (CNS) via nerveterminal.Rabies has been part of the history of civilization for several millennia, rooted inits enzootic environment (animal host) and causing severe threats to public health.The number of human deaths and the circumstances, with over95%of rabies victimsreported residing in Asia and Africa and nearly all victims of a rabid animal bite.Rabies and the symptoms it presents can hardly be ignored, yet it appears to be undulyneglected in some parts of the world, notably in Asia and Africa, where the spread ofcanine rabies is not under control and is far from being eliminated. To control rabiesincidence, an effective way is enhance the immunization rate of cats or canines byrabies vaccine, and the best way to immunize animals is oral rabies vaccination.However, there are various problems with commercial vaccines that they can’t bepractically used till now. Thus, there is a need to develop a novel vaccines withhigh-efficiency, available oral vaccination and low-cost rabies vaccine.Live vaccines based on recombinant viruses have played an important role in thedevelopment of new vaccines. Live attenuated pseudorabies virus (PRV) has beenproven as an excellent vector for expression and delivery of heterologous antigens inthe development of recombinant vaccines against infectious diseases in the last30years due to a number of advantageous characteristics. Besides swains, PRV alsoinfected dogs and cats, and replicated in vivo. An observed role in the nasal mucosa isthe character of PRV, and its role is clear now. A notably well-studied strain,Bartha-K61strain, was widely used in the past, and it has the potential to be a safetyvaccine vector for its marked genome background.Since the G is the only surface-exposed viral coat protein, it is capable ofeliciting synthesis of neutralization antibody. To construct a recombinant virusexpressing G gene of Rabies virus, we constructed a recombinant pseudorabies viruswith the G gene and LacZ cassette, avoiding the correct folding of the glycoprotein. By homologous recombination, a new recombinant virus was generated andnamed as rPRV-LacZ-G. After purification by blue-plaque, its biological characterswere invested. Using electron microscopy analysis, it is indicated recombinant PRVassembly in the BHK-21cells with virion. The virus titer was slightly decented whileits reproductive cycle was remaining, comparing to Bartha-K61. In vitro, therecombinant virus (rPRV-LacZ-G) can express glycoprotein of rabies virus effectively.To test the protective immunity, mice and cats were inoculated by oral orintramscular injection. A specific band correlating with the glycoprotein of rabiesvirus was detected in infected hosts’ blood serum by Western blot analysis. Futher, wealso tested the effect of different administration routes on immunization by thefluorescent antibody virus neutralization (FAVN) test. Oral immunization elicitedlower immune response against the foreign antigen than intramuscular inoculation.In this research, the recombinant virus rPRV-LacZ-G expressing the foreignantigen (glycoprotein of rabies virus) could induce the synthesis of neutralizationantibody against rabies virus after intramuscular injection or oral immunization washarvest, which paved way for the development of a novel rabies vaccine in the nearfuture. |
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