Vaccines (Mar 2024)

A <i>Streptococcus suis</i> Strain Δ<i>cps/ssna</i>-m<i>sly</i> (P353L)-SC19 Provides Cross-Protection against Serotypes 2 and 9 Strain Challenges in a Mouse Model

  • Xi Lu,
  • Lei Xu,
  • Lan Lin,
  • Liting Zhou,
  • Bingqian Dai,
  • Shuyue Cui,
  • Anding Zhang

DOI
https://doi.org/10.3390/vaccines12030283
Journal volume & issue
Vol. 12, no. 3
p. 283

Abstract

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Streptococcus suis is an important zoonotic pathogen that mainly causes meningitis, septicemia, and arthritis. Due to the limited cross-protection between numerous serotypes, the existing inactive vaccines in clinical use fail to offer sufficient protection. In this study, a gene deletion-attenuated strain Δcps/ssna-msly (P353L)-SC-19 was constructed by deleting cps and ssna genes from the epidemic strain SC-19 with a mutation of SLY (P353L). The safety of Δcps/ssna-msly (P353L)-SC-19 was confirmed in both in vitro and in vivo experiments. We further demonstrated that immunization with Δcps/ssna-msly (P353L)-SC-19 induced significant cellular immunity and humoral immunity in mice and protected against infections caused by type 2 strain SC-19 (100% protection) and type 9 strain S29 (50% protection), while also preventing meningitis induced by S29. This study highlights the potential of using CPS-deficient strains to achieve cross-protection against different Streptococcus suis serotypes and develop a promising universal live vaccine.

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