Gonçalves, Lídia M. D.Almeida, António J.Calado, Cecília2024-11-042024-11-042024-09GONÇALVES, Lídia M. D.; ALMEIDA, António J.; CALADO, Cecília R. C. – Impact of neutrophil-activating protein conservation on diagnostic tests and vaccine design. Journal of Chemical Technology and Biotechnology. eISSN 1097-4660. (2024), https://doi.org/10.1002/jctb.7755http://hdl.handle.net/10400.21/17824BACKGROUND: The neutrophil activating protein (NAP) is a highly immunogenic and virulence factor of Helicobacter pylori, pre-senting inflammatory and immunomodulatory activity. Consequently, NAP has been explored as a diagnostic and therapeutictarget. However, when evaluating a target protein to design diagnostic methods or vaccines, it is critical to determine the pro-tein conservation among the bacterial population, as well the impact of alterations of amino acid residues on the protein anti-genic profile. RESULTS: In the present work, NAP conservation and theoretical antigenicity were determined among 51 sequences fromH. pylori isolated from patients worldwide. A high NAP conservation (83%) was observed, where 17 amino acid residues, amongthe 144 residues of the protein, were polymorphic. Alterations at these polymorphic sites had a theoretically low impact on pre-dicted antigenicity, where only 5 NAPs out of 51 NAPs presented a slightly different antigenic profile in relation to the consen-sus sequence. According to that, it was possible to recognize in western blotting 93% of NAP from different bacteria (n = 15) using polyclonal antibodies developed against a specific NAP. CONCLUSIONS: It was predicted that when working with polyclonal antibodies or large NAP fragments for diagnostic and vaccine design, slight variation in protein sequence will have a minimal impact on NAP recognition. However, if a NAP monoclonal antibody or small NAP epitopes are considered, it is critical to select the most conserved and antigenic NAP regions, to maximize the coverage of NAP variants.engHelicobacter pyloriNAPimmunogenicgenetic variabilityneutrophil-activating proteinimmunovariabilityjournal article10.1002/jctb.77551097-4660