Scientists from Korea use single-cell RNA analysis to reveal key immune mechanisms in lungs of swine infected with PRRSV

Understanding the immune responses triggered upon infection with porcine reproductive and respiratory syndrome virus (PRRSV) will facilitate vaccine development and disease management, protecting the swine industry and associated economy. Scientists in Korea reveal changes in immune cell composition in lungs during infection with PRRSV of varying severity. They identified regulators of cell death in severe infections, and protective immune cells in infection with virus of intermediate strength, paving the way for targeted disease management.

Image title: Bacterial epidermitis induced by opportunistic infection in PRRSV-infected pigs.

Image caption: PRRSV infection in growing pigs is a significant drawback for the swine industry. The study findings reveal that differing virulence of PRRSV triggers distinct immune responses in the lungs of the infected animal. Improved understanding of immune mechanisms will aid in efficient disease management and development of vaccines and targeted therapeutics.

Image credit: College of Veterinary Medicine, Jeonbuk National University

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Porcine reproductive and respiratory syndrome virus (PRRSV) infection in pigs is economically devastating for the global swine industry. The viral infection leads to reproductive disorder in sows and respiratory problems in infected newborn and growing pigs. Unfortunately, high genetic variability of the virus and differing disease-causing strength or virulence hinders vaccine development and complicates disease management. Not much is known of the factors contributing to viral disease severity or the anti-viral immune responses.

Dr. Jun-Mo Kim, Associate Professor at the Department of Animal Science and Technology, Chung-Ang University, Korea has focused his research efforts on filling this gap in understanding. “Using a PRRSV infection model, our goal is to advance the comprehensive understanding of the infection and response mechanism in order to minimize industrial damage,” shared Dr. Kim. Recently, his group analyzed protein-coding RNA transcripts isolated from single cells and fluid collected from lungs of PRRSV-infected pigs. They monitored immune cell alterations triggered by PRRSV strains of varying virulence. This paper was made available online on January 28, 2025 and was published in Volume 16 Issue 1 of Nature Communications.

The study shows that high virulence PRRSV strain triggered early, severe lung damage and overall immune imbalance marked by significant reduction in macrophages. In contrast, PRRSV strain of intermediate strength led to delayed lung damage with fewer immune alterations. Importantly, higher numbers of protective anti-inflammatory M2-like macrophages (SPP1-CXCL14high) were observed in less virulent infections, suggesting a potential role in promoting lung healing.

While fewer than 5% of macrophages were directly infected by virus, cell death and immune responses were widespread indicating that extracellular vesicles or exosomes containing microRNAs released from the PRRSV-infected cells likely contributed to pathogenesis and cell death in non-infected bystander cells.

“Our study findings will aid the development of innovative therapeutic strategies with the potential to mitigate severe lung damage and promote efficient recovery in PRRSV-infected animals, paving the way for effective viral disease management,” explains Dr. Kim, elaborating on the long-term implications of their findings. In addition to the obvious impact on livestock health, global food security, and in securing the economy of the swine industry, the findings from this study may find a parallel in other human respiratory viruses and therapeutic strategies are likely to be applicable and effective broadly.

With these insights, researchers are one step closer to turning scientific discovery into real-world solutions that safeguard both animal and human health.

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About Chung-Ang University

Chung-Ang University is a private comprehensive research university located in Seoul, South Korea. It was started as a kindergarten in 1916 and attained university status in 1953. It is fully accredited by the Ministry of Education of Korea. Chung-Ang University conducts research activities under the slogan of “Justice and Truth” Its new vision for completing 100 years is “The Global Creative Leader” Chung-Ang University offers undergraduate, postgraduate, and doctoral programs, which encompass a law school, management program, and medical school; it has 16 undergraduate and graduate schools each. Chung-Ang University’s culture and arts programs are considered the best in Korea.

Website: https://neweng.cau.ac.kr/index.do

About Dr. Jun-Mo Kim

Dr. Jun-Mo Kim is Associate Professor at the Department of Animal Science and Technology, Chung-Ang University, Korea. His research focuses on holistic approaches to identify biological mechanisms and biomarkers in animal and veterinary medicine. Dr. Kim and his team employ systems biology and integration of multi-omics data to understand livestock genomics. In 2011, Dr. Kim received his PhD degree in Animal Molecular Biology from Korea University. Prior to joining Chung-Ang University, he completed postdoctoral training at National Institute of Animal Science, University of Queensland, and University of Sheffield. He has over 105 publications to his credit with significant editorial contributions.

Website: https://scholarworks.bwise.kr/cau/researcher-profile?ep=1063