HpaA IgY prevents the infection of helicobacter pylori in vivo

Objective To prepare HpaA IgY against Helicobacter pylori from yolk of egg laid from hen immunized with recombinant protein HpaA,based on constructed gene engineering bacteria pQE30-HpaA-DH5α of Helicobacter pylori. Methods After pQE30-HpaA-DH5α was cultured,mass HpaA recombinant proteins were induced and expressed,and then purified by Ni2+-NAT chromatography. Laying hens were immunized with the fusion protein HpaA and the obtained IgY was isolated using method of the water dilution combined ammonium sulfate precipitation. The purity,titer,protein content,and specificity of IgY were detected by SDS-PAGE,ELISA,Bradford,and Western blotting,respectively. Before infection with H.pylori,Balb/c mice were administrated with different dosages of HpaA IgY by using an oral feeding needle in the prevention group. The planting of bacteria in stomach was assayed by observing bacterial culture and pathological section. Results HpaA recombinant proteins were expressed and IgY was prepared successfully. The concentration and purity of IgY were 24.6 mg/mL and 90%,respectively. The titer of IgY was 1∶12 800. The total rate of infection in the positive control was 70.4% and after 12 weeks the infection rate was raised to 88.9%. The infection rate of the prevention group was lower than that of the positive control group at the same infected period,and was negatively related to the addition of IgY. The dosage of HpaA IgY that can prevent the infection of H.pylori was 6 mg/mL. Conclusion HpaA IgY with high concentration,high purity,high titer,and specificity is successfully prepared,which is able to inhibit the adhesive attraction of H. pylori in vivo and be used to prevent H. pylori infection.