Preventive effect of anti-VacA egg yolk immunoglobulin (IgY) on Helicobacter pylori-infected mice

•Anti-VacA IgY reduced significantly serum levels of anti- H. pylori antibodies.•Anti-VacA IgY decreased eosinophilic infiltration in gastric mucosa of mice.•Anti-VacA IgY suppressed immunopositivity in gastric mucosa of mice. Helicobacter pylori, a gram-negative bacterium, is the causative agent of gastric disorders and gastric cancer in the human stomach. Vacuolating cytotoxin A (VacA) is among the multi-effect protein toxins released by H. pylori that enables its persistence in the human stomach. To evaluate the effect of anti-VacA egg yolk immunoglobulin (anti-VacA IgY) on H. pylori infection, a highly specific anti-VacA IgY was produced from egg yolks of hens immunized with a mixture of two purified recombinant VacAs. Female C57BL/6 mice were supplemented anti-VacA IgY daily with drinking water for 2 weeks before and 4 weeks after H. pylori ATCC 43504 inoculation. Anti-VacA IgY recognized both native and denatured structures of VacA by enzyme-linked immunosorbent assay and immunoblotting analyses, respectively. Oral administration of anti-VacA IgYs significantly (p