Abstract: Macrophage phenotypic adaptation critically regulates inflammatory balance during infection; however, progress in equine immunology has been limited by a lack of specific tools for standardized identification. To address this gap, we established a reliable, antibody-based detection method for characterizing equine macrophage M1-like and M2-like marker profiles. After initially validating canonical marker genes via qPCR, we developed specific monoclonal antibodies targeting the differentially expressed surface proteins CD80 (M1-like) and CD163 (M2-like). These novel antibodies enabled the creation of a multi-modal detection approach combining flow cytometry, western blotting, and qPCR. Applying this methodology revealed distinct pathogen-specific marker profiles: , equine herpesvirus (EHV-1), and equine arteritis virus (EAV) promoted an early M1-like profile, whereas an attenuated equine infectious anemia virus (EIAV) strain drove an M2-like phenotype. Ultimately, this work provides a validated detection system for equine macrophage phenotyping, establishing a critical foundation for future research into host-pathogen interactions and targeted therapeutics.IMPORTANCEMacrophage phenotypic adaptation plays a critical role in infectious diseases, as pathogens often manipulate these states to evade immune responses or drive damaging inflammation. Accurately monitoring these functional shifts is vital for guiding disease treatment and evaluating vaccines. However, standardized detection tools for equine macrophages have been lacking. In this study, we established a reliable, antibody-based method utilizing novel monoclonal antibodies against equine CD80 and CD163 to identify M1-like and M2-like marker profiles. This straightforward and highly specific approach overcomes the limitations of previous indirect methods, providing a critical, accessible tool for assessing macrophage responses to equine pathogens and advancing veterinary immunology.
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Overview
This research developed and validated specific antibody-based methods to accurately detect and distinguish different functional states (M1-like and M2-like) of equine macrophages.
The new detection system enables better understanding of how equine macrophages respond to various pathogenic infections, facilitating improved studies and therapeutic strategies.
Introduction and Background
Macrophages are immune cells that adapt their functional phenotype in response to infection and inflammation.
The two main activation states—M1-like (pro-inflammatory) and M2-like (anti-inflammatory or tissue repair)—critically regulate immune balance.
Pathogens often manipulate macrophage polarization to evade immune defenses or promote damaging inflammation.
Despite their importance, progress in studying equine macrophages has been hampered by a lack of specific, standardized detection methods for these phenotypes.
To create tools capable of distinguishing M1-like and M2-like macrophages using surface proteins rather than indirect gene expression alone.
To apply these new tools in experiments with different equine pathogens to observe resultant macrophage phenotype changes.
Methodological Approach
Validated known macrophage polarization markers (canonical genes) using quantitative PCR (qPCR).
Developed monoclonal antibodies targeting key surface proteins:
CD80 as a marker for M1-like macrophages
CD163 as a marker for M2-like macrophages
Combined these specific antibody tools into a multi-modal detection system including flow cytometry, western blotting, and qPCR.
Key Findings
The new monoclonal antibodies efficiently and specifically identified M1-like and M2-like equine macrophage populations.
Different equine pathogens induced distinct macrophage polarization profiles:
Equine herpesvirus 1 (EHV-1) and equine arteritis virus (EAV) triggered an early M1-like, pro-inflammatory phenotype.
An attenuated strain of equine infectious anemia virus (EIAV) promoted an M2-like, anti-inflammatory phenotype.
These results demonstrate that macrophage phenotypes can be pathogen-specific and dynamically regulated during infection.
Significance and Implications
This work fills a critical gap in equine immunology by providing standardized, validated tools to detect and monitor macrophage polarization states.
The antibody-based approach is straightforward, specific, and applicable in multiple laboratory assays, improving accuracy over previous indirect detection methods.
Having reliable detection of macrophage states is essential to investigate host-pathogen interactions in horses, guiding the development of targeted immunotherapies and better vaccine evaluations.
The methodology can accelerate research into how equine macrophages respond to infection, inflammation, and potentially other disease contexts beyond infectious agents.
Conclusions
The study successfully established novel monoclonal antibodies against equine CD80 and CD163 as markers of macrophage polarization.
Implementing a multi-modal detection framework enabled clear identification of distinct M1-like and M2-like macrophages in horses.
These tools revealed differential macrophage activation profiles depending on the infectious pathogen, highlighting their biological relevance.
This validated detection system constitutes a foundational resource to standardize equine macrophage research and facilitate improved immunological investigations in veterinary medicine.
Cite This Article
APA
Chen K, Du C, Duan Y, Guo K, Liu D, Wang F, Wang X, Wen Y.
(2026).
Systematic establishment of approaches to the detection of equine macrophage polarization and their application in pathogenic infection.
Microbiol Spectr, 14(8), e0291625.
https://doi.org/10.1128/spectrum.02916-25
Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases of Ministry of Agriculture, College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, China.
State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
Du, Cheng
State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
Duan, Yingyi
State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
Guo, Kui
State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
Liu, Diqiu
State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
Wang, Fengxue
Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases of Ministry of Agriculture, College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, China.
Wang, Xiaojun
State Key Laboratory of Animal Disease Control and Prevention, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
Wen, Yongjun
Key Laboratory for Clinical Diagnosis and Treatment of Animal Diseases of Ministry of Agriculture, College of Veterinary Medicine, Inner Mongolia Agricultural University, Hohhot, China.
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