Phenotypic and genotypic analyses of an attenuated porcine reproductive and respiratory syndrome virus strain after serial passages in cultured porcine alveolar macrophages
10.4142/jvs.2018.19.3.358
- Author:
Seung Chul LEE
1
;
Sunhee LEE
;
Gun Woo YOO
;
Hwan Won CHOI
;
Yun Hee NOH
;
Chang Eon PARK
;
Jae Ho SHIN
;
In Joong YOON
;
Shien Young KANG
;
Changhee LEE
Author Information
1. Choongang Vaccine Laboratory, Daejeon 34055, Korea.
- Publication Type:Original Article
- Keywords:
attenuated vaccines;
macrophage tropism;
porcine reproductive and respiratory syndrome virus;
virulence;
whole genome sequencing
- MeSH:
Animals;
Antibody Formation;
Body Temperature;
Genetic Drift;
Humans;
Kinetics;
Macrophages;
Macrophages, Alveolar;
Parents;
Phenotype;
Porcine Reproductive and Respiratory Syndrome;
Porcine respiratory and reproductive syndrome virus;
Swine;
Tropism;
Vaccines, Attenuated;
Viremia;
Virulence;
Weight Gain
- From:Journal of Veterinary Science
2018;19(3):358-367
- CountryRepublic of Korea
- Language:English
-
Abstract:
The porcine reproductive and respiratory syndrome virus (PRRSV) is a globally ubiquitous swine viral pathogen that causes major economic losses worldwide. We previously reported an over-attenuated phenotype of cell-adapted PRRSV strain CA-2-P100 in vivo. In the present study, CA-2-P100 was serially propagated in cultured porcine alveolar macrophage (PAM) cells for up to 20 passages to obtain the derivative strain CA-2-MP120. Animal inoculation studies revealed that both CA-2-P100 and CA-2-MP120 had decreased virulence, eliciting weight gains, body temperatures, and histopathologic lesions similar to those in the negative control group. However, compared to CA-2-P100 infection, CA-2-MP120 yielded consistently higher viremia kinetics and enhanced antibody responses in pigs. All pigs inoculated with CA-2-MP120 developed viremia and seroconverted to PRRSV. During 20 passages in PAM cells, CA-2-MP120 acquired 15 amino acid changes that were mostly distributed in nsp2 and minor structural protein-coding regions. Among these changes, 6 mutations represented reversions to the sequences of the reference CA-2 and parental CA-2-P20 strains. These genetic drifts may be hypothetical molecular markers associated with PRRSV macrophage tropism and virulence. Our results indicate that the PAM-passaged CA-2-MP120 strain is a potential candidate for developing a live, attenuated PRRSV vaccine.
