Bovine Anti- Helicobacter pylori Antibodies for Oral Immunotherapy

Abstract

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.