has role protective antigen role protective antigen Neisseria meningitidis protein LpdA protein Allen Xiang Protegen ID: 596; NCBI Protein GI: 1017430; NCBITaxon: 487 Oliver He Sera of the challenge group immunized with CCPS-P64kR showed a three-fold higher bactericidal response than the sera of the group immunized with the plain CCPS and they were able to protect against challenge with Neisseria meningococci in the infant rat protection model [PubMed: 15039094].