Study On Cross-protection Of Sera After Vaccination With Different Rabies Vaccines

Objective Rabies is a fatal disease caused by rabies virus. Vaccination is animportant means to prevent the onset of disease. There’s a variety of strain of therabies virus, The vaccine needs to stimulate the body to produce broadly neutralizingantibodies to be effective in preventing rabies. It’s important that vaccine can producecross-protection between vaccine strains and epidemic strains. In order to verify theability of cross-protection between the different strains, the neutralizing activity ofserum after immunization with different vaccines were analyzed. The different virushave different number and location of G protein glycosylation sites,and someglycosylation sites of the membrane protein of HIV-1and other enveloped virusescause the virus to escape the role of antibodies.Therefore,this study also verifiedwhether the rabies virus G protein glycosylation can produce the same effect on rabiesvirus.Methods This study uses pseudovius system to verify the ability ofcross-protection between epidemic strains and the vaccine strains of the rabies virus inChina, and verify the impact of the virus G protein glycosylation. We used four rabiesvaccines prepared from different strains to immune balb/c mice and detected theneutralizing activity of serum. Eukaryotic plasmids expressing the rabies virus Gprotein and plasmid expressing HIV gag/pol and plasmid expressing the luciferasereporter gene were co-transfected293T cells to generate pseudovirus.The pseudoviruscan infect BHK-21cells and mediate the luciferase gene expression,which is a singleround of infection. The pseudovirus infected the target cells after incubated withserum.Then we detected the antibody activity of serum according to the level ofluciferase expression. We Increased or decreased the glycosylation sites on the virusG protein by the method of site-directed mutagenesis and detected the infection ability of the mutant virus and serum neutralizing activity to virus.Results Succesfully generated CVS-11,CTN and aG strain pseudovirus carryingluciferase gene,which could infect BHK-21cells and mediate luciferaseexpression.Mices immuned with different rabies vaccine produced antibodies againstthe pseudovirus. Glycosylation of the204and247amino acids on the virus impactedthe infection ability of virus.But the glycosylated virus couldn’t escape the role ofantibodies.Conclusions We detected the cross-protection between epidemic strains andvaccine strains rabies by pseudovirus and we knew that glycosylation of the204and247animo acid on G protein couldn’t allow the virus to escpe the antibodies.Althoughdifferent vaccines made from different strains,but the vaccines can generate broadlyimmune protection. The pseudovirus can further evaluate the applicability and qualityof rabies vaccines.