Bovine anti-Helicobacter pylori antibodies for oral immunotherapy

Background: Passive immunization with orally administered antibodies against specific pathogens has previously been successfully used therapeutically in both animal and human studies. We employed a similar strategy for experimental treatment of mice infected with the gastric pathogen Helicobacter pylori. Methods: An anti-H. pylori bovine colostral hyperimmune immunoglobulin preparation (BIC) was generated and its efficacy was tested in different in vitro experiments, such as binding to the Lewis(b) blood group antigen, inhibition of adherence of H. pylori to human gastric mucosa tissue sections in situ and in a haemagglutination assay. The BIC preparation was also given in the drinking water to H. pylori-infected mice. Results: An inhibition of 95% of the binding of H. pylori to Lewis(b) glycoconjugate was observed in vitro. Furthermore, a blocking activity of almost 90% was observed when the BIC was preincubated with H. pylori bacteria. Finally, the BIC preparation inhibited the haemagglutination of H. pylori and human red blood cells. Seven of 40 (17.5%) mice remained infected in the treatment group as compared with 25 of 45 (55.5%) in the control group. Hence, the cure rate was 66%, P = < 0.001. The mean number of colonies in the antibody-treated mice where eradication was not successful was also reduced (P < 0.05). In trials using FVB/N transgenic Lewis(b) expressing mice, a cure rate of 50%-66% was observed. Conclusion: Bovine colostral antibodies against H. pylori can be generated in high titres, inhibit binding in vitro and can eradicate or reduce the number of bacteria in infected mice.