Article ID: JJID.2021.795
Novel immunodominant antigens are urgently required for diagnosis and vaccine of Helicobacter pylori(HP). FliD, an important colonization factor was cloned and expressed(rFliD) to evaluate the levels of specific-IgG, IgM and IgA antibodies in the serum of patients by ELISA. Rabbit anti-rFliD polyclonal antibody (pAb) was obtained by subcutaneous injections of rFliD. The rFliD-specific IFN-γ and IL-4 of peripheral blood mononuclear cells and CD4+ T cells from human were analyzed by enzyme-linked immunospot and flow cytometry. We found that the levels of rFliD-specific IgG, IgM and IgA were significantly higher in HP-infected-patients compared with healthy controls. IgG, IgM and IgA had diagnostic sensitivities of 92.6, 89.8 and 83.2%; specificities of 91.1, 88.7 and 64.6%; and areas under the receiver operating curves of 0.97, 0.96 and 0.92, respectively. Furthermore, rFliD-pAb was used in the immunohistochemical analysis of gastritis and gastric cancer tissues from patients infected with HP. The levels of rFliD-specific IFN-γ and IL-4 were significantly elevated in HP-infected patients and exhibited a T helper type 1-dominant subtype. These findings indicate that rFliD exhibits high validity as a biomarker in HP diagnosis and may also be a potent antigen for vaccine design due to its high cellular and humoral immune response.