Rapid screening and identification of dominant B cell epitopes of UreB protein by fluorescence polarization assay

In order to develop a new method for screening and identification of dominant B cell epitopes using UreB protein as a target antigen 11 amino acid fragments from UreB protein of Helicobacter pylori (Hp) were synthesized by Fmoc solid phase peptide synthesis strategy, and fluorescein FITC was labeled to the N-terminals of all peptides respectively. The antigenicity of synthetic peptides is determined by analyzing the recognition and combination between peptides and standard antibody samples by fluorescence polarization (FP) immunoassay. In order to screen the dominant antigenic peptides, the FP assays were carried out to investigate the antibodies against 10 UreB synthetic peptides respectively in 159 UreB antibody-positive antiserum samples. There are 10 of 11 UreB synthetic peptides have distinct antigenicity by FP assay. The results showed that 3 out of the 10 antigenic peptides may be immunodominant, for the antibodies against them existed more widely among the samples and the antibody titers were higher than those of other peptides's. The methods for predicting and identifying epitopes are useful for epitope mapping, and the fluorescence polarized method for antibody immunoassay can be widely used in the diagnosis, typing and therapy of diseases in clinic in the future.