Detection And Immunogenicity Of Porcine Rotavirus Protein Expressed By Cordyceps Militaris

Rotavirus is one of the main causes of acute gastroenteritis in infants and young animals all over the world.Because there is no specific treatment for diarrhea caused by rotavirus,vaccines play an important role in the prevention and treatment of rotavirus.Traditional vaccines have some disadvantages,such as high cost and intussusception.Therefore,it is a challenge for people to develop new and safer vaccines.Porcine rotavirus VP4 and VP7 are viral coat proteins and play important roles in viral clearance and immune protection.VP7 protein,as the most important component of rotavirus shell,can induce neutralizing antibodies.VP4 protein is located on the surface of virus particles and forms ridges.Under the action of trypsinase,VP4 protein can be cleaved into VP8* and VP5*.VP8* is highly conservative among the same serotypes and can stimμLate homotypic protection.In this study,Cordyceps militaris strains which successfμLly transformed VP7,VP8*,VP7-8* genes of rotavirus were used as materials to verify the expression of VP7,VP8*,VP7-8* proteins.The immunogenicity of VP7,VP8*,VP7-8* proteins was analyzed by immunizing mice and suckling mice.The conclusions are as follows:1.The expression of target protein of recombinant VP7 Cordyceps militaris strain,VP8* Cordyceps militaris strain and VP7-8* Cordyceps militaris strain was detected by ELISA.The target protein VP7-VP8* accounted for 0.035‰ of Cordyceps militaris freeze-dried powder,the target protein VP7 accounted for 0.0174‰ of Cordyceps militaris freeze-dried powder,and the target protein VP8* accounted for 0.016‰.2.The mice were immunized with recombinant VP7 Cordyceps militaris strain,VP8 Cordyceps militaris strain and VP7-8 Cordyceps militaris strain freeze-dried powder orally.The mice in the immunized group coμLd produce saliva,feces,intestinal mucosa IgA antibody and serum IgG antibody.The mice in the VP7-8* group produced saliva,feces,intestinal mucosa IgA antibody and serum IgG antibody higher than those in the VP7 and VP8* groups,with significant differences.3.The serum antibodies of mice immunized with VP7,VP8* and VP7-8* had viral neutralization ability.The viral neutralization ability of mice immunized with VP7-8* Cordyceps militaris was higher than that of mice immunized with VP7 and VP8* Cordyceps militaris.4.The effect of neutralizing virus in VP7-8* group was the best.This study selected this group to continue the suckling experiment.The mice immunized with VP7-8* group coμLd passively immunize offspring mice,and the offspring of mice immunized with VP7-8* group had antiviral ability and mild diarrhea symptoms.5.This study laid the foundation for vaccine production in bacterial bioreactor and provided a new production mode for the research of rotavirus vaccine.