Immunogenicity and Protective Capacity of Sugar ABC Transporter Substrate-Binding Protein against <i>Streptococcus suis</i> Serotype 2, 7 and 9 Infection in Mice
Zujie Yan,
Ruyi Pan,
Junjie Zhang,
Jianhe Sun,
Xiaochun Ma,
Nihua Dong,
Xiaohui Yao,
Jianchao Wei,
Ke Liu,
Yafeng Qiu,
Katie Sealey,
Hester Nichols,
Michael A. Jarvis,
Mathew Upton,
Xiangdong Li,
Zhiyong Ma,
Juxiang Liu,
Beibei Li
Affiliations
Zujie Yan
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China
Ruyi Pan
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China
Junjie Zhang
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China
Jianhe Sun
Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
Xiaochun Ma
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China
Nihua Dong
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China
Xiaohui Yao
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China
Jianchao Wei
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China
Ke Liu
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China
Yafeng Qiu
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China
Katie Sealey
School of Cellular and Molecular Medicine, University of Bristol, University Walk, Bristol BS8 1TD, UK
Hester Nichols
The Vaccine Group Ltd., Plymouth PL6 8BU, UK
Michael A. Jarvis
The Vaccine Group Ltd., Plymouth PL6 8BU, UK
Mathew Upton
School of Biomedical Sciences, University of Plymouth, Plymouth PL4 8AA, UK
Xiangdong Li
School of Biomedical Sciences, University of Plymouth, Plymouth PL4 8AA, UK
Zhiyong Ma
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China
Juxiang Liu
College of Veterinary Medicine, Hebei Agricultural University, Baoding 071000, China
Beibei Li
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Science, Shanghai 200241, China
Background: Streptococcus suis (S. suis) is a Gram-positive bacterium that causes substantial disease in pigs. S. suis is also an emerging zoonoses in humans, primarily in Asia, through the consumption of undercooked pork and the handling of infected pig meat as well as carcasses. The complexity of S. suis epidemiology, characterized by the presence of multiple bacterial serotypes and strains with diverse sequence types, identifies a critical need for a universal vaccine with the ability to confer cross-protective immunity. Highly conserved immunogenic proteins are generally considered good candidate antigens for subunit universal vaccines. Methods: In this study, the cross-protection of the sugar ABC transporter substrate-binding protein (S-ABC), a surface-associated immunogenic protein of S. suis, was examined in mice for evaluation as a universal vaccine candidate. Results: S-ABC was shown to be highly conserved, with 97% amino acid sequence identity across 31 S. suis strains deposited in GenBank. Recombinantly expressed S-ABC (rS-ABC) was recognized via rabbit sera specific to S. suis serotype 2. The immunization of mice with rS-ABC induced antigen-specific antibody responses, as well as IFN-γ and IL-4, in multiple organs, including the lungs. rS-ABC immunization conferred high (87.5% and 100%) protection against challenges with S. suis serotypes 2 and 9, demonstrating high cross-protection against these serotypes. Protection, albeit lower (50%), was also observed in mice challenged with S. suis serotype 7. Conclusions: These data identify S-ABC as a promising antigenic target within a universal subunit vaccine against S. suis.
