title: Efficacy of commercial genotype 1 porcine reproductive and respiratory syndrome virus (PRRSV) vaccine against field isolate of genotype 2 PRRSV.
abstract: Although several recent studies have found that type 1 porcine reproductive and respiratory syndrome virus (PRRSV) modified live virus (MLV) vaccine showed appreciable levels of cross-protection against type 2 PRRSV infection, the possibility of cross-protection between two genotype of PRRSV is still controversial. To determine potential protective efficacy against hetero-genotype field strain of PRRSV and to improve understandings of the mechanisms underlying performance improvement after infection in vaccinated animals, piglets were vaccinated with type 1 PRRSV MLV vaccine and challenged with type 2 field strain of PRRSV. As a result, vaccinated animals gained on average 8.45 kg in comparison to 4.77 kg measured in non-vaccinated animals during a 3-week period after viral challenge, which shows using a certain PRRSV vaccine could be clinically effective against heterologous genotypic virus challenge. In vaccinated animals, viremia was reduced and cleared rapidly, whilst viral load was much higher and reduced more slowly, indicating rebound viremia in non-vaccinated animals. The titers of neutralizing antibody against the type 2 PRRSV did not exceed the protective level in any animal from both vaccinated and control groups. Instead, antibody avidity of vaccinated animals was much higher than in the control group clearly. Furthermore, a strong negative correlation between antibody avidity and viremia was noted in 80% of vaccinated animals. Through those results from tests evaluating degree of antibody maturation and its relevance with clearing viremia, it could be suggested that non-neutralizing antibodies induced by vaccination prior to challenge might play a key role in protection against PRRSV infection, especially in early time course.
authors.affiliation: Department of Immunopathology, College of Veterinary Medicine, Konkuk University, Neung-dong Street 120, Gwangjin-ku, Seuol, South Korea.
authors.forename: Seong-sik
authors.initials: SS
authors.lastname: Ko
authors.affiliation: Department of Immunopathology, College of Veterinary Medicine, Konkuk University, Neung-dong Street 120, Gwangjin-ku, Seuol, South Korea.
authors.forename: Sang-won
authors.initials: SW
authors.lastname: Seo
authors.affiliation: Department of Immunopathology, College of Veterinary Medicine, Konkuk University, Neung-dong Street 120, Gwangjin-ku, Seuol, South Korea.
authors.forename: Sun-young
authors.initials: SY
authors.lastname: Sunwoo
authors.affiliation: Department of Immunopathology, College of Veterinary Medicine, Konkuk University, Neung-dong Street 120, Gwangjin-ku, Seuol, South Korea.
authors.forename: Sung J
authors.initials: SJ
authors.lastname: Yoo
authors.affiliation: Hipra Korea, Inc., Jeongjail-ro 177, Bundang-gu, Seongnam-si, Gyeonggi-do, South Korea.
authors.forename: Myung-hyee
authors.initials: MH
authors.lastname: Kim
authors.affiliation: Department of Immunopathology, College of Veterinary Medicine, Konkuk University, Neung-dong Street 120, Gwangjin-ku, Seuol, South Korea. Electronic address: lyoo@konkuk.ac.kr.
authors.forename: Young S
authors.initials: YS
authors.lastname: Lyoo
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000276:immunology; D000914:Antibodies, Viral / Q000276:immunology; D016207:Cytokines / Q000097:blood; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005838:Genotype; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology / Q000517:prevention & control*; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D013047:Specific Pathogen-Free Organisms; D013552:Swine; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D016207:Cytokines; D014765:Viral Vaccines
keywords: Avidity; Challenge; Immunity; Porcine reproductive and respiratory syndrome virus; Vaccine