title: Comparison of protection provided by type 1 and type 2 porcine reproductive and respiratory syndrome field viruses against homologous and heterologous challenge.
abstract: The objective of this study was to compare protection provided by type 1 and type 2 porcine reproductive and respiratory syndrome virus (PRRSV) against homologous and heterologous challenge based on clinical, virological, immunological, and pathological analysis. At 3 and 8 weeks of age, pigs were inoculated intranasally with either 3mL of tissue culture fluid containing 10(5) TCID50/mL of type 1 PRRSV or 3mL of tissue culture fluid containing 10(5) TCID50/mL of type 2 PRRSV. The homologous challenges resulted in a significant boost of the neutralizing antibodies (NA) and interferon-γ secreting cells (IFN-γ-SC) compared to heterologous challenges. The reduction of secondary challenging PRRSV viremia coincided with the appearance of homologous PRRSV-specific NA and IFN-γ-SC. Homologous challenge reduced the severity of lung lesions and levels of PRRSV viremia significantly in pigs in comparison with heterologous challenge. The differences in homologous and heterologous NA and IFN-γ-SC response may explain the differences in protection against homologous and heterologous challenge between type 1 and type 2 PRRSV. Primary challenge (immunization) with type 1 PRRSV provided protection against the secondary homologous challenge with type 1 PRRSV but failed to provide protection against the secondary heterologous challenge of type 2 PRRSV. Primary challenge with type 2 PRRSV provided protection against both the secondary homologous challenge with type 2 PRRSV and the secondary heterologous challenge with type 1 PRRSV.
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: 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.
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. Electronic address: swine@snu.ac.kr.
authors.forename: Chanhee
authors.initials: C
authors.lastname: Chae
mesh_terms: D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood / Q000276:immunology; D056738:Cross Protection / Q000276:immunology*; D007114:Immunization / Q000592:standards / Q000662:veterinary*; D008168:Lung / Q000473:pathology; D019318:Porcine Reproductive and Respiratory Syndrome / Q000276:immunology* / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D011897:Random Allocation; D013552:Swine
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral
keywords: Genotype; Heterologous challenge; Homologous challenge; Porcine reproductive and respiratory syndrome virus