Preliminary assessment of correlation between T-lymphocyte responses and control of porcine reproductive and respiratory syndrome virus (PRRSV) in piglets born after in-utero infection of a type 2 PRRSV

Cha, Sang-Ho; Bandaranayaka-Mudiyanselage, Carey; Bandaranayaka-Mudiyanselage, Chandima B.; Ajiththos, Dharani; Yoon, Kyoung-Jin; Gibson, Kathleen A.; Yu, Ji-Eun; Cho, In-Soo; Lee, Stephen S.; Chung, Chungwon J.

doi:2018.58.1.9

Korean J Vet Res > Volume 58(1); 2018 > Article

Original Article

Korean Journal of Veterinary Research 2018;58(1):9-16.
DOI: https://doi.org/10.14405/kjvr.2018.58.1.9 Published online May 8, 2018.

Preliminary assessment of correlation between T-lymphocyte responses and control of porcine reproductive and respiratory syndrome virus (PRRSV) in piglets born after in-utero infection of a type 2 PRRSV

Sang-Ho Cha¹, Carey Bandaranayaka-Mudiyanselage², Chandima B. Bandaranayaka-Mudiyanselage², Dharani Ajiththos³, Kyoung-Jin Yoon⁴, Kathleen A. Gibson⁴, Ji-Eun Yu¹, In-Soo Cho¹, Stephen S. Lee⁵, Chungwon J. Chung²

¹Animal and Plant Quarantine Agency
²VMRD Inc.
³Department of Veterinary Microbiology and Pathology, Washington State University
⁴Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University
⁵University of Idaho

Abstract

A preliminary study into the protective mechanisms of adaptive immunity against porcine reproductive and respiratory syndrome virus (PRRSV) in piglets (n = 9) born to a gilt challenged intranasally with a type-2 PRRSV. Immune parameters (neutralizing antibodies, $CD3^+CD4^+$, $CD3^+CD8^+$, $CD3^+CD4^+CD8^+$ T-lymphocytes, and PRRSV-specific interferon $(IFN)-{gamma}$ secreting T-lymphocytes) were compared with infection parameters (macro- and microscopic lung lesion, and PRRSV-infected porcine alveolar macrophages ($CD172{alpha}^+PRRSV-N^+;PAM$) as well as with plasma and lymphoid tissue viral loads. Percentages of three T-lymphocyte phenotypes in 14-days post-birth (dpb) peripheral blood mononuclear cell (PBMC) had significant negative correlations with percentages of $CD172{alpha}^+PRRSV-N^+;PAM$ (p < 0.05) as well as with macroscopic lung lesion (p < 0.01). Plasma and tissue viral loads had significant (p < 0.05) negative correlations with $CD3^+CD4^+CD8^+$ T-lymphocyte percentage in PBMC. Frequencies of $CD3^+CD8^+$ and $CD3^+CD4^+$ T-lymphocytes in 14-dpb PBMC had significant negative correlations with of lymph node (p = 0.04) and lung (p = 0.002) viral loads. $IFN-{gamma}$-secreting T-lymphocytes frequency had a significant negative correlation with gross lung lesion severity (p = 0.002). However, neutralizing antibody titers had no significant negative correlation (p > 0.1) with infection parameters. The results indicate that T-lymphocytes contribute to controlling PRRSV replication in young piglets born after in-utero infection.

Key Words: T-lymphocyte, neutralizing antibodies, porcine reproductive and respiratory syndrome virus