Association of Pneumococcal Protein Antigen Serology With Age and Antigenic Profile of Colonizing Isolates

J Infect Dis. 2017 Mar 1;215(5):713-722. doi: 10.1093/infdis/jiw628.


Background: Several Streptococcus pneumoniae proteins play a role in pathogenesis and are being investigated as vaccine targets. It is largely unknown whether naturally acquired antibodies reduce the risk of colonization with strains expressing a particular antigenic variant.

Methods: Serum immunoglobulin G (IgG) titers to 28 pneumococcal protein antigens were measured among 242 individuals aged <6 months-78 years in Native American communities between 2007 and 2009. Nasopharyngeal swabs were collected >- 30 days after serum collection, and the antigen variant in each pneumococcal isolate was determined using genomic data. We assessed the association between preexisting variant-specific antibody titers and subsequent carriage of pneumococcus expressing a particular antigen variant.

Results: Antibody titers often increased across pediatric groups before decreasing among adults. Individuals with low titers against group 3 pneumococcal surface protein C (PspC) variants were more likely to be colonized with pneumococci expressing those variants. For other antigens, variant-specific IgG titers do not predict colonization.

Conclusion: We observed an inverse association between variant-specific antibody concentration and homologous pneumococcal colonization for only 1 protein. Further assessment of antibody repertoires may elucidate the nature of antipneumococcal antibody-mediated mucosal immunity while informing vaccine development.

Keywords: PspA; PspC; Streptococcus pneumoniae; immunology; pilus; pneumococci; protein antigens; sera; vaccine; antibody.

Publication types

  • Observational Study

MeSH terms

  • Adolescent
  • Adult
  • Age Factors*
  • Aged
  • Antibodies, Bacterial / blood*
  • Antigens, Bacterial / blood*
  • Antigens, Bacterial / immunology
  • Bacterial Proteins / blood
  • Carrier State / immunology
  • Carrier State / microbiology
  • Child
  • Child, Preschool
  • Follow-Up Studies
  • Heat-Shock Proteins / blood
  • Humans
  • Immunoglobulin G / blood
  • Infant
  • Logistic Models
  • Longitudinal Studies
  • Middle Aged
  • Nasopharynx / microbiology
  • Pneumococcal Infections / blood*
  • Pneumococcal Infections / immunology
  • Prospective Studies
  • Young Adult


  • Antibodies, Bacterial
  • Antigens, Bacterial
  • Bacterial Proteins
  • Heat-Shock Proteins
  • Immunoglobulin G
  • SpsA protein, Streptococcus pneumoniae
  • phage shock protein, Bacteria