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Function of neisserial outer membrane phospholipase a in autolysis and assessment of its vaccine potential

Martine P Bos1, Boris Tefsen, Pierre Voet

  • 1Department of Molecular Microbiology and Institute for Biomembranes, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands. m.p.bos@bio.uu.nl

Infection and Immunity
|March 24, 2005
PubMed

Insights

Outer membrane phospholipase A (OMPLA) is present in many pathogenic bacteria, including Neisseria meningitidis. However, OMPLA showed limited vaccine potential due to poor immunogenicity in mice and humans.

Area of Science:

  • Microbiology
  • Enzymology
  • Vaccinology

Background:

  • Outer membrane phospholipase A (OMPLA) is an enzyme found in many Gram-negative bacteria, contributing to pathogen virulence.
  • Its role in the human pathogen Neisseria meningitidis, particularly its function and vaccine potential, required investigation.

Purpose of the Study:

  • To determine the presence and expression of OMPLA in Neisseria meningitidis.
  • To characterize the enzymatic function and autolytic activity of OMPLA.
  • To evaluate the vaccine potential of OMPLA against Neisseria meningitidis.

Main Methods:

  • Immunoblot analysis to detect OMPLA presence in various Neisseria strains.
  • Phenotypic analysis of isogenic strains with varying OMPLA expression levels.
  • Immunization of mice with recombinant OMPLA and assessment of antibody responses, bactericidal activity, and protection.

Main Results:

  • OMPLA was detected in most Neisseria meningitidis strains, with variations in expression. OMPLA was also found in Neisseria gonorrhoeae but less so in commensal Neisseria species.
  • OMPLA demonstrated phospholipase activity against endogenous phospholipids and acted as an autolysin under specific conditions.
  • While immunization generated high antibody titers in mice, these antibodies were not bactericidal or protective. Anti-OMPLA antibodies were also not detected in convalescent patients or vaccinees.

Conclusions:

  • OMPLA is expressed by pathogenic Neisseria species and possesses enzymatic and autolytic functions.
  • The protein's limited immunogenicity suggests it may not be a suitable candidate for inclusion in a Neisseria meningitidis vaccine.

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