Immunologic properties and therapeutic efficacy of a multivalent epitope‐based vaccine against four <i>Helicobacter pylori</i> adhesins (urease, Lpp20, HpaA, and CagL) in <i>Mongolian gerbils</i>

Abstract

Abstract Background Therapeutic vaccination is a desirable alternative for controlling Helicobacter pylori ( H. pylori ) infection. Attachment to the gastric mucosa is the first step in establishing bacterial colonization, and adhesins, which are on the surface of H. pylori , play a pivotal role in binding to human gastric mucosa. Materials and Methods In the present study, we constructed a multivalent epitope‐based vaccine named CFA dE with seven carefully selected antigenic fragments from four H. pylori adhesins (urease, Lpp20, HpaA and CagL). The specificity, immunogenicity and ability to produce neutralizing antibodies of CFA dE were evaluated in BALB /c mice. After that, its therapeutic efficacy and protective immune mechanisms were explored in H. pylori ‐infected Mongolian gerbils. Results The results indicated that CFA dE could induce comparatively high levels of specific antibodies against urease, Lpp20, HpaA and CagL. Additionally, oral therapeutic immunization with CFA dE plus polysaccharide adjuvant ( PA ) significantly decreased H. pylori colonization compared with oral immunization with urease plus PA , and the protection was correlated with IgG and sIgA antibody and antigen‐specific CD 4 + T cells. Conclusions This study indicated that the multivalent epitope‐based vaccine, which targeted multiple adhesins in adherence of H. pylori to the gastric mucosa, is more effective than the univalent vaccine targeting urease only. This multivalent epitope‐based vaccine may be a promising therapeutic candidate vaccine against H. pylori infection.