title: Immunization with Streptococcus suis bacterin plus recombinant Sao protein in sows conveys passive immunity to their piglets.
abstract: BACKGROUND
  Streptococcus suis (S. suis) causes arthritis, meningitis, septicemia, and sudden death in pigs and is also an zoonotic agent for humans. The present study demonstrated that immunization with recombinant Sao-L (surface antigen one-L, rSao-L) protein from a strain of S. suis serotype 2 in pigs was able to increase cross-serotype protection against S. suis serotype 1 and 2 challenge. Since weaning piglets are more susceptible to S. suis infections due to the stresses associated with weaning, prepartum immunization in sows may convey passive immunity to piglets and provide protection.
  
  
  RESULTS
  Pregnant sows were immunized with a vaccine containing inactivated S. suis serotype 2 plus rSao as the antigens. Blood samples were collected from their piglets after birth for analysis of antigen-specific antibody titers and levels of various cytokines. Results demonstrated that the titers of S. suis and rSao-specific antibodies were significantly (p < 0.05) higher in the vaccinated piglets in comparison with that of piglets in the control group. The serum levels of interferon (IFN)-γ, interleukin (IL)-4, IL-6, and IL-12 were significantly (p < 0.05) increased in piglets born from vaccinated sows when compared to piglets from unvaccinated sows. In addition, piglets were challenged by heterologous and homologous S. suis. All piglets from unvaccinated sows developed severe symptoms of bacteremia, fever, anorexia, depression, and arthritis. On the other hand, piglets from vaccinated sows had significantly (p < 0.05) reduced clinical symptoms and lesion score (by 75 and 81%).
  
  
  CONCLUSIONS
  Our results revealed that immunizing pregnant sows with the vaccine containing inactivated S. suis bacterin plus rSao as the antigens is able to enhance passive immunity against heterologous and homologous S. suis challenge in their piglets.
authors.affiliation: Department of Veterinary medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, 91201, Taiwan.|Graduate Institute of Animal Vaccine Technology, College of Veterinary Medicine, National Pingtung University of Science and Technology, 1, Shuehfu Road, Neipu, Pingtung, 91201, Taiwan.
authors.forename: Kai-Jen
authors.initials: KJ
authors.lastname: Hsueh
authors.affiliation: Graduate Institute of Animal Vaccine Technology, College of Veterinary Medicine, National Pingtung University of Science and Technology, 1, Shuehfu Road, Neipu, Pingtung, 91201, Taiwan.
authors.forename: Li-Ting
authors.initials: LT
authors.lastname: Cheng
authors.affiliation: Department of Tropical Agriculture and International Cooperation, National Pingtung University of Science and Technology, Pingtung, 91201, Taiwan.
authors.forename: Jai-Wei
authors.initials: JW
authors.lastname: Lee
authors.affiliation: Graduate Institute of Animal Vaccine Technology, College of Veterinary Medicine, National Pingtung University of Science and Technology, 1, Shuehfu Road, Neipu, Pingtung, 91201, Taiwan.
authors.forename: Yao-Chi
authors.initials: YC
authors.lastname: Chung
authors.affiliation: Department of Veterinary medicine, College of Veterinary Medicine, National Pingtung University of Science and Technology, Pingtung, 91201, Taiwan. wbchung@mail.npust.edu.tw.
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Chung
authors.affiliation: Graduate Institute of Animal Vaccine Technology, College of Veterinary Medicine, National Pingtung University of Science and Technology, 1, Shuehfu Road, Neipu, Pingtung, 91201, Taiwan. cychu@mail.npust.edu.tw.
authors.forename: Chun-Yen
authors.initials: CY
authors.lastname: Chu
mesh_terms: D000375:Aging; D000818:Animals; D001426:Bacterial Proteins / Q000276:immunology*; D001428:Bacterial Vaccines / Q000276:immunology*; D016207:Cytokines / Q000097:blood / Q000235:genetics / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology; D007112:Immunity, Maternally-Acquired; D007114:Immunization; D007116:Immunization, Passive / Q000662:veterinary; D011247:Pregnancy; D011994:Recombinant Proteins; D017011:Streptococcus suis / Q000276:immunology* / Q000378:metabolism; D013552:Swine; D013553:Swine Diseases / Q000382:microbiology / Q000517:prevention & control*
chemical_list: D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D016207:Cytokines; D011994:Recombinant Proteins
keywords: Cytokine; Passive immunity; Streptococcus suis; Vaccine; rSao