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.
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.
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.
Serum immunoglobulin G (IgG) titers to 28 pneumococcal protein antigens were measured among 242 individuals aged - 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.
Azarian T, Grant LR, Georgieva M, Hammitt LL, Reid R, Bentley SD, Goldblatt D, Santosham M, Weatherholtz R, Burbidge P, Goklish N, Thompson CM, Hanage WP, O'Brien KL, Lipsitch M. (2017). Association of Pneumococcal Protein Antigen Serology With Age and Antigenic Profile of Colonizing Isolates. The Journal of infectious diseases, 215(5)