The importance of Helicobacter pylori's genetic variability for the construction of an efficient vaccine

Helicobacter pylori is responsible for several gastric diseases. The main constraints of vaccine trials against this pathogen are mainly due to the bacterium high antigenic variability and to down-regulation of the host immune responses. To counteract these factors we propose a DNA vaccine able to induce a balanced humoural and citotoxic specific immune responses, based on multi-antigens. The selection of the antigens NapA, HpaA, VacA and HomB were conducted based on immunoproteomic data and the protein role on infection and pathogenesis. A fragment of each target-antigen was selected by in silico methods based on the maximization of the gene conservation and antigenicity. The set of these small fragments will be presented as a vaccine based on several conserved epitopes of multi-antigenic targets, and consequently representative of the bacterium antigenic variability.