title: Evaluation of a 20year old porcine reproductive and respiratory syndrome (PRRS) modified live vaccine (Ingelvac(®) PRRS MLV) against two recent type 2 PRRS virus isolates in South Korea.
abstract: Type 2 porcine reproductive and respiratory syndrome (PRRS) virus (PRRSV) was first isolated in Korea in 1994. The commercial PRRS modified live vaccine (Ingelvac(®) PRRS MLV, Boehringer Ingelheim Vetmedica Inc., St. Joseph, Missouri, USA) based on type 2 PRRSV, was first licensed for use in 3- to 18-week-old pigs in Korea in 1996. The objective of the present study was to evaluate the efficacy of this 20year old commercial PRRS modified live vaccine (MLV) against two recent PRRSV isolates. Two genetically distant type 2 PRRSV strains (SNUVR150004 for lineage 1 and SNUVR150324 for lineage 5), isolated in 2015, were used as challenge virus. Regardless of the challenge virus, vaccination of pigs effectively reduced the level of viremia, the lung lesions, and of the PRRSV antigen within the lung lesions. The induction of virus-specific interferon-γ secreting cells by the PRRS vaccine produced a protective immune response, leading to the reduction of PRRSV viremia. There were no significant differences in efficacy against the two recently isolated viruses by the PRRS MLV based on virological results, immunological responses, and pathological outcomes. This study demonstrates that the PRRS MLV used in this study is still effective against recently isolated heterologous type 2 PRRSV strains even after 20 years of use in over 35 million pigs.
authors.affiliation: Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.
authors.forename: Jiwoon
authors.initials: J
authors.lastname: Jeong
authors.affiliation: Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.
authors.forename: Kyuhyung
authors.initials: K
authors.lastname: Choi
authors.affiliation: Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.
authors.forename: Ikjae
authors.initials: I
authors.lastname: Kang
authors.affiliation: Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea.
authors.forename: Changhoon
authors.initials: C
authors.lastname: Park
authors.affiliation: Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 151-742, Republic of Korea. Electronic address: swine@snu.ac.kr.
authors.forename: Chanhee
authors.initials: C
authors.lastname: Chae
mesh_terms: D000818:Animals; D015967:Gene Expression Regulation, Viral; D010802:Phylogeny; D019318:Porcine Reproductive and Respiratory Syndrome / Q000517:prevention & control*; D019316:Porcine respiratory and reproductive syndrome virus / Q000145:classification* / Q000235:genetics; D012367:RNA, Viral / Q000097:blood; D013552:Swine; D014759:Viral Envelope Proteins / Q000235:genetics; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D012367:RNA, Viral; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; C114789:glycoprotein 5, PRRSV
keywords: PRRSV modified live vaccine; Porcine reproductive and respiratory syndrome virus; Respiratory disease; Vaccine efficacy