Association of pneumococcal protein antigen serology with age and antigenic profile of colonizing isolates

T Azarian, LR Grant, M Georgieva… - The Journal of …, 2017 - academic.oup.com
T Azarian, LR Grant, M Georgieva, LL Hammitt, R Reid, SD Bentley, D Goldblatt
The Journal of Infectious Diseases, 2017academic.oup.com
Abstract 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 …
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.
Oxford University Press