Comparison of Two Commercial Type 1 Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) Modified Live Vaccines against Heterologous Type 1 and Type 2 PRRSV Challenge in Growing Pigs

• Published in: Clinical and vaccine immunology 2015-06, Vol.22 (6), p.631-640
• Main Authors: Kim, Taeyeon, Park, Changhoon, Choi, Kyuhyung, Jeong, Jiwoon, Kang, Ikjae, Park, Su-Jin, Chae, Chanhee
• Format: Article
• Language: English
• Subjects: Animals; Cross Protection; Interferon-gamma - secretion; Interleukin-10 - blood; Leukocytes, Mononuclear - immunology; Lung - pathology; Porcine Reproductive and Respiratory Syndrome - immunology; Porcine Reproductive and Respiratory Syndrome - prevention & control; Porcine respiratory and reproductive syndrome virus; Porcine respiratory and reproductive syndrome virus - genetics; Porcine respiratory and reproductive syndrome virus - immunology; Swine; Vaccines; Vaccines, Attenuated - administration & dosage; Vaccines, Attenuated - genetics; Vaccines, Attenuated - immunology; Vaccines, Synthetic - administration & dosage; Vaccines, Synthetic - genetics; Vaccines, Synthetic - immunology; Viral Vaccines - administration & dosage; Viral Vaccines - genetics; Viral Vaccines - immunology; Viremia - prevention & control
• ISSN: 1556-6811; 1556-679X
• DOI: 10.1128/CVI.00001-15

The objective of the present study was to compare the efficacy of two commercial type 1 porcine reproductive and respiratory syndrome virus (PRRSV) modified live vaccines against heterologous type 1 and type 2 PRRSV challenge in growing pigs. Vaccination with a type 1 PRRSV vaccine reduced the level of viremia after type 1 PRRSV challenge but did not reduce the level of viremia after the type 2 PRRSV challenge in pigs. Increased levels of interleukin-10 (IL-10) stimulated by type 2 PRRSV coincided with the low numbers of type 2 PRRSV-specific interferon gamma-secreting cells (IFN-γ-SC) in vaccinated pigs after type 2 PRRSV challenge, whereas low levels of IL-10 stimulated by type 1 PRRSV coincided with high numbers of type 1 PRRSV-specific IFN-γ-SC in vaccinated pigs after type 1 PRRSV challenge. Additionally, vaccination with the type 1 PRRSV vaccine effectively reduced the lung lesions and type 1 PRRSV nucleic acids in type 1 PRRSV-challenged pigs but did not reduce lung lesions and type 2 PRRSV nucleic acids in type 2 PRRSV-challenged pigs. There were no significant differences between two commercial type 1 PRRSV vaccines against type 1 and type 2 PRRSV challenge based on virological results, immunological responses, and pathological outcomes. This study demonstrates that vaccinating pigs with the type 1 PRRSV vaccine provides partial protection against respiratory disease with heterologous type 1 PRRSV challenge but no protection with heterologous type 2 PRRSV challenge.