Streptococcus suis surface-antigen recognition by antibodies and bacterial elimination is influenced by capsular polysaccharide structure

Front Cell Infect Microbiol. 2023 Jul 21:13:1228496. doi: 10.3389/fcimb.2023.1228496. eCollection 2023.

Abstract

Streptococcus suis is an encapsulated bacterium causing severe diseases in swine. Here, we compared the protective properties of the capsular polysaccharide (CPS) of different S. suis serotypes by using serotype-switched mutants in a mouse model of infection. CPS structure influenced bacterial survival in mice, antibody binding, and antibody-mediated bacterial killing. The CPS of serotypes 3, 4 and 14 allowed more antibody binding and bacterial elimination than the CPS of serotypes 2, 7 and 9. Results suggest that the different CPS structures of S. suis provide varying levels of protection by influencing antigen availability and elimination by the host immune system.

Keywords: Streptococcus suis; antibody; capsular polysaccharide; mouse; serotype.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antibodies
  • Antibodies, Bacterial
  • Bacterial Capsules
  • Mice
  • Polysaccharides, Bacterial
  • Serogroup
  • Streptococcal Infections* / microbiology
  • Streptococcus suis* / metabolism
  • Swine

Substances

  • Polysaccharides, Bacterial
  • Antibodies
  • Antibodies, Bacterial

Grants and funding

This work was mainly supported by the Natural Sciences and Engineering Research Council of Canada (NSERC) through grants to MS (no. 342150) and to MG (no. 04435). DD is the recipient of a Fonds de Recherche du Québec–Nature et Technologies (FRQ-NT) Doctoral Research Scholarship (#268339) and the recipient of a Swine and Poultry Infectious Disease Research Center (CRIPA) scholarship supported by the FRQNT (#RS-170946). MS is a holder of a Canada Research Chair – Tier 1.