A preliminary study on the application of PspA as a carrier for group A meningococcal polysaccharide

PLoS One. 2019 Jul 10;14(7):e0218427. doi: 10.1371/journal.pone.0218427. eCollection 2019.

Abstract

This study aimed to explore the feasibility of pneumococcal surface protein A (PspA) as a carrier protein. Three recombinant pneumococcal surface proteins from three different clades were expressed by the prokaryotic expression system and conjugated to group A meningococcal polysaccharide (GAMP) to generate three polysaccharide-protein conjugates. The conjugates, unconjugated proteins, GAMP, and GAMP-TT vaccine bulk (used as positive control) were immunized into mice, and their immune effects were assessed by the methods of enzyme-linked immunosorbent assay (ELISA), flow cytometry (FCM), and serum bactericidal assay (SBA). The results showed that the polysaccharide-protein conjugates could produce higher levels of anti-GAMP IgG titers (P < 0.05), higher ratios of Th1/Th2 (P < 0.05), and higher levels of serum bactericidal activity (P < 0.05), compared with the unconjugated GAMP. The conjugation of PspAs to GAMP also enhanced the anti-PspA responses compared with unconjugated PspAs except for PspA3. In conclusion, the results indicated that the three PspAs were appropriate carrier proteins, as demonstrated by the characteristics of T-cell dependent responses to the GAMP, and might protect against group A of epidemic cerebrospinal meningitis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies, Bacterial / immunology
  • Bacterial Proteins / immunology
  • Bacterial Proteins / pharmacology*
  • Female
  • Immunoglobulin G / immunology
  • Meningococcal Infections / immunology*
  • Meningococcal Infections / prevention & control
  • Meningococcal Vaccines / immunology
  • Meningococcal Vaccines / pharmacology*
  • Mice
  • Mice, Inbred BALB C
  • Neisseria meningitidis / immunology
  • Polysaccharides, Bacterial / immunology
  • Polysaccharides, Bacterial / pharmacology*
  • Preliminary Data
  • Vaccines, Conjugate / immunology
  • Vaccines, Conjugate / pharmacology

Substances

  • Antibodies, Bacterial
  • Bacterial Proteins
  • Immunoglobulin G
  • Meningococcal Vaccines
  • Polysaccharides, Bacterial
  • Vaccines, Conjugate
  • meningococcal group A polysaccharide
  • pneumococcal surface protein A

Grants and funding

This research was provided financial support by National high-tech research and development plan (project 863), project number: 2012AA02A402. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.