title: The assessment of efficacy of porcine reproductive respiratory syndrome virus inactivated vaccine based on the viral quantity and inactivation methods.
abstract: BACKGROUND
  There have been many efforts to develop efficient vaccines for the control of porcine reproductive and respiratory syndrome virus (PRRSV). Although inactivated PRRSV vaccines are preferred for their safety, they are weak at inducing humoral immune responses and controlling field PRRSV infection, especially when heterologous viruses are involved.
  
  
  RESULTS
  In all groups, the sample to positive (S/P) ratio of IDEXX ELISA and the virus neutralization (VN) titer remained negative until challenge. While viremia did not reduce in the vaccinated groups, the IDEXX-ELISA-specific immunoglobulin G increased more rapidly and to significantly greater levels 7 days after the challenge in all the vaccinated groups compared to the non-vaccinated groups (p < 0.05). VN titer was significantly different in the 106 PFU/mL PRRSV vaccine-inoculated and binary ethylenimine (BEI)-inactivated groups 22 days after challenge (p < 0.05). Consequently, the inactivated vaccines tested in this study provided weak memory responses with sequential challenge without any obvious active immune responses in the vaccinated pigs.
  
  
  CONCLUSIONS
  The inactivated vaccine failed to show the humoral immunity, but it showed different immune response after the challenge compared to mock group. Although the 106 PFU/mL-vaccinated and BEI-inactivated groups showed significantly greater VN titers 22 days after challenge, all the groups were already negative for viremia.
authors.affiliation: Optifarm Solution Inc., 48 Songnam-ri, Seonggeo-eup, Cheonan, Korea.
authors.forename: Hyunil
authors.initials: H
authors.lastname: Kim
authors.forename: Hye Kwon
authors.initials: HK
authors.lastname: Kim
authors.forename: Jung Ho
authors.initials: JH
authors.lastname: Jung
authors.forename: Yoo Jung
authors.initials: YJ
authors.lastname: Choi
authors.forename: Jiho
authors.initials: J
authors.lastname: Kim
authors.forename: Chang Gyu
authors.initials: CG
authors.lastname: Um
authors.forename: Su Bin
authors.initials: SB
authors.lastname: Hyun
authors.forename: Sungho
authors.initials: S
authors.lastname: Shin
authors.forename: Byeongchun
authors.initials: B
authors.lastname: Lee
authors.forename: Goo
authors.initials: G
authors.lastname: Jang
authors.forename: Bo Kyu
authors.initials: BK
authors.lastname: Kang
authors.forename: Hyoung Joon
authors.initials: HJ
authors.lastname: Moon
authors.forename: Dae Sub
authors.initials: DS
authors.lastname: Song
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay; D007074:Immunoglobulin G / Q000097:blood; D007156:Immunologic Memory; D009500:Neutralization Tests; D019318:Porcine Reproductive and Respiratory Syndrome / Q000517:prevention & control*; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D013552:Swine; D015164:Vaccines, Inactivated / Q000008:administration & dosage / Q000276:immunology; D019562:Viral Load; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*; D014766:Viremia / Q000517:prevention & control
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D007074:Immunoglobulin G; D015164:Vaccines, Inactivated; D014765:Viral Vaccines