Equine Arteritis Virus Has Specific Tropism for Stromal Cells and CD8+ T and CD21+ B Lymphocytes but Not for Glandular Epithelium at the Primary Site of Persistent Infection in the Stallion Reproductive Tract.
Abstract: Equine arteritis virus (EAV) has a global impact on the equine industry as the causative agent of equine viral arteritis (EVA), a respiratory, systemic, and reproductive disease of equids. A distinctive feature of EAV infection is that it establishes long-term persistent infection in 10 to 70% of infected stallions (carriers). In these stallions, EAV is detectable only in the reproductive tract, and viral persistence occurs despite the presence of high serum neutralizing antibody titers. Carrier stallions constitute the natural reservoir of the virus as they continuously shed EAV in their semen. Although the accessory sex glands have been implicated as the primary sites of EAV persistence, the viral host cell tropism and whether viral replication in carrier stallions occurs in the presence or absence of host inflammatory responses remain unknown. In this study, dual immunohistochemical and immunofluorescence techniques were employed to unequivocally demonstrate that the ampulla is the main EAV tissue reservoir rather than immunologically privileged tissues (i.e., testes). Furthermore, we demonstrate that EAV has specific tropism for stromal cells (fibrocytes and possibly tissue macrophages) and CD8+ T and CD21+ B lymphocytes but not glandular epithelium. Persistent EAV infection is associated with moderate, multifocal lymphoplasmacytic ampullitis comprising clusters of B (CD21+) lymphocytes and significant infiltration of T (CD3+, CD4+, CD8+, and CD25+) lymphocytes, tissue macrophages, and dendritic cells (Iba-1+ and CD83+), with a small number of tissue macrophages expressing CD163 and CD204 scavenger receptors. This study suggests that EAV employs complex immune evasion mechanisms that warrant further investigation.IMPORTANCE The major challenge for the worldwide control of EAV is that this virus has the distinctive ability to establish persistent infection in the stallion's reproductive tract as a mechanism to ensure its maintenance in equid populations. Therefore, the precise identification of tissue and cellular tropism of EAV is critical for understanding the molecular basis of viral persistence and for development of improved prophylactic or treatment strategies. This study significantly enhances our understanding of the EAV carrier state in stallions by unequivocally identifying the ampullae as the primary sites of viral persistence, combined with the fact that persistence involves continuous viral replication in fibrocytes (possibly including tissue macrophages) and T and B lymphocytes in the presence of detectable inflammatory responses, suggesting the involvement of complex viral mechanisms of immune evasion. Therefore, EAV persistence provides a powerful new natural animal model to study RNA virus persistence in the male reproductive tract.
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The study discusses how the Equine Arteritis Virus (EAV) uniquely affects specific cells within a stallion’s reproductive tract, establishing persistent infection despite the immune response. It provides critical insight into understanding the EAV’s carrier state in stallions and offers a natural animal model for studying RNA virus persistence in the male reproductive tract.
Research Context
This research is based on Equine Arteritis Virus (EAV), a globally recognized disease that affects horses. EAV is the cause of equine viral arteritis (EVA), a disease with respiratory, systemic, and reproductive impacts.
EAV manages to establish persistent infections in 10 to 70% of infected stallions, despite existing neutralizing antibody responses in the horses. This ability to persist makes the ‘carrier’ stallions the natural virus reservoir, as they continually shed the virus in their semen.
However, the focus of EAV persistence, as well as the specifics of its interaction with different cell types (its “tropism”), was previously unknown, driving the need for this research.
Findings and Implications
The researchers used advanced techniques to confirm that the main tissue reservoir of EAV is the ampulla within the stallion’s reproductive tract, rather than the testes which were previously suggested as possible sites.
The study found that EAV specifically targets stromal cells (like fibrocytes and possibly tissue macrophages) and two types of lymphocytes (CD8 T and CD21 B cells), but it leaves the glandular epithelium unaffected. This specific targeting is referred to as the virus’s ‘tropism’.
Persistent EAV infection was associated with observable inflammation symptoms, defined as ‘ampullitis’, which involved the aggregation of the targeted lymphocytes and infiltration of other immune cells. This could suggest a complex interplay between the virus and the host’s immune response.
Understanding EAV’s cellular tropism, persistence mechanisms, and immune system interactions can contribute to better prevention or treatment strategies against EVA.
The results also open up a new natural animal model to study RNA virus persistence in the male reproductive tract, which could be of significant use in other virology studies.
Cite This Article
APA
Carossino M, Loynachan AT, Canisso IF, Cook RF, Campos JR, Nam B, Go YY, Squires EL, Troedsson MHT, Swerczek T, Del Piero F, Bailey E, Timoney PJ, Balasuriya UBR.
(2017).
Equine Arteritis Virus Has Specific Tropism for Stromal Cells and CD8+ T and CD21+ B Lymphocytes but Not for Glandular Epithelium at the Primary Site of Persistent Infection in the Stallion Reproductive Tract.
J Virol, 91(13).
https://doi.org/10.1128/JVI.00418-17
Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.
Loynachan, Alan T
University of Kentucky Veterinary Diagnostic Laboratory, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.
Canisso, Igor F
Department of Veterinary Clinical Medicine and Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois Urbana-Champaign, Urbana, Illinois, USA.
Cook, R Frank
Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.
Campos, Juliana R
Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.
Nam, Bora
Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.
Go, Yun Young
Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.
Virus Research and Testing Group, Division of Drug Discovery Research, Korea Research Institute of Chemical Technology, Yuseong-gu, Daejeon, South Korea.
Squires, Edward L
Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.
Troedsson, Mats H T
Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.
Swerczek, Thomas
Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.
Del Piero, Fabio
Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, Louisiana, USA.
Bailey, Ernest
Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.
Timoney, Peter J
Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA.
Balasuriya, Udeni B R
Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, College of Agriculture, Food and Environment, University of Kentucky, Lexington, Kentucky, USA ubalasuriya@uky.edu.
MeSH Terms
Animals
Arterivirus Infections / veterinary
Arterivirus Infections / virology
B-Lymphocytes / virology
CD8-Positive T-Lymphocytes / virology
Epithelium / virology
Equartevirus / physiology
Fluorescent Antibody Technique
Genitalia / virology
Horse Diseases / virology
Horses
Immunohistochemistry
Male
Stromal Cells / virology
Viral Tropism
References
This article includes 119 references
Cavanagh D. Nidovirales: a new order comprising Coronaviridae and Arteriviridae. Arch Virol 142:629–633.
Balasuriya U, MacLachlan NJ. 2013. Equine viral arteritis, p 169–181. In Sellon DC, Long MT (ed), Equine infectious diseases, 2nd ed Saunders, St. Louis, MO.
Balasuriya UB, Go YY, MacLachlan NJ. Equine arteritis virus. Vet Microbiol 167:93–122.
Balasuriya UBR, Carossino M, Timoney PJ. Equine viral arteritis: a respiratory and reproductive disease of significant economic importance to the equine industry. Equine Vet Educ .
Lopez JW, del Piero F, Glaser A, Finazzi M. Immunoperoxidase histochemistry as a diagnostic tool for detection of equine arteritis virus antigen in formalin fixed tissues. Equine Vet J 28:77–79.
Campos JR. Effects on semen quality and on establishment of persistent equine arteritis virus (EAV) infection in stallions following experimental challenge with the Kentucky 84 (KY84) strain. .
Balasuriya UBR, Sarkar S, Carossino M, Go YY, Chelvarajan L, Cook RF, Loynachan AT, Timoney PJ, Bailey E. Host factors that contribute to equine arteritis virus persistence in the stallion: an update. J Equine Vet Sci 43 (Suppl):S11–S17.
Hills SL, Russell K, Hennessey M, Williams C, Oster AM, Fischer M, Mead P. Transmission of Zika virus through sexual contact with travelers to areas of ongoing transmission—continental United States, 2016. MMWR Morb Mortal Wkly Rep 65:215–216.
Barzon L, Pacenti M, Franchin E, Lavezzo E, Trevisan M, Sgarabotto D, Palu G. Infection dynamics in a traveller with persistent shedding of Zika virus RNA in semen for six months after returning from Haiti to Italy, January 2016. Euro Surveill 21:30316.
Danilenko DM, Rossitto PV, Van der Vieren M, Le Trong H, McDonough SP, Affolter VK, Moore PF. A novel canine leukointegrin, alpha d beta 2, is expressed by specific macrophage subpopulations in tissue and a minor CD8+ lymphocyte subpopulation in peripheral blood. J Immunol 155:35–44.
Ito D, Imai Y, Ohsawa K, Nakajima K, Fukuuchi Y, Kohsaka S. Microglia-specific localisation of a novel calcium binding protein, Iba1. Brain Res Mol Brain Res 57:1–9.
Ahmed Z, Shaw G, Sharma VP, Yang C, McGowan E, Dickson DW. Actin-binding proteins coronin-1a and IBA-1 are effective microglial markers for immunohistochemistry. J Histochem Cytochem 55:687–700.
Yamaguchi T, Fushida S, Yamamoto Y, Tsukada T, Kinoshita J, Oyama K, Miyashita T, Tajima H, Ninomiya I, Munesue S, Harashima A, Harada S, Yamamoto H, Ohta T. Tumor-associated macrophages of the M2 phenotype contribute to progression in gastric cancer with peritoneal dissemination. Gastric Cancer 19:1052–1065.
Rugtveit J, Scott H, Halstensen TS, Norstein J, Brandtzaeg P. Expression of the L1 antigen (calprotectin) by tissue macrophages reflects recent recruitment from peripheral blood rather than upregulation of local synthesis: implications for rejection diagnosis in formalin-fixed kidney specimens. J Pathol 180:194–199.
Alvarez B, Sanchez C, Bullido R, Marina A, Lunney J, Alonso F, Ezquerra A, Dominguez J. A porcine cell surface receptor identified by monoclonal antibodies to SWC3 is a member of the signal regulatory protein family and associates with protein-tyrosine phosphatase SHP-1. Tissue Antigens 55:342–351.
Herrmann-Hoesing LM, Noh SM, Snekvik KR, White SN, Schneider DA, Truscott T, Knowles DP. Ovine progressive pneumonia virus capsid antigen as found in CD163- and CD172a-positive alveolar macrophages of persistently infected sheep. Vet Pathol 47:518–528.
Gulbahar MY, Davis WC, Yuksel H, Cabalar M. Immunohistochemical evaluation of inflammatory infiltrate in the skin and lung of lambs naturally infected with sheeppox virus. Vet Pathol 43:67–75.
Nalubamba KS, Gossner AG, Dalziel RG, Hopkins J. Differential expression of pattern recognition receptors in sheep tissues and leukocyte subsets. Vet Immunol Immunopathol 118:252–262.
Di Carlo E, Magnasco S, D'Antuono T, Tenaglia R, Sorrentino C. The prostate-associated lymphoid tissue (PALT) is linked to the expression of homing chemokines CXCL13 and CCL21. Prostate 67:1070–1080.
Nguyen PV, Kafka JK, Ferreira VH, Roth K, Kaushic C. Innate and adaptive immune responses in male and female reproductive tracts in homeostasis and following HIV infection. Cell Mol Immunol 11:410–427.
Zaneveld LJD, Anderson DJ, Whaley KJ, Quayle AJ. 1996. Appendix D, barrier methods and mucosal immunologic approaches, p 430–473. In Harrison PF, Rosenfield A (ed), Contraceptive research and development: looking to the future. National Academies Press, Washington, DC.
Carossino M, Loynachan AT, James MacLachlan N, Drew C, Shuck KM, Timoney PJ, Del Piero F, Balasuriya UB. Detection of equine arteritis virus by two chromogenic RNA in situ hybridization assays (conventional and RNAscope (®) and assessment of their performance in tissues from aborted equine fetuses. Arch Virol 161:3125–3136.
Cecere TE, Todd SM, Leroith T. Regulatory T cells in arterivirus and coronavirus infections: do they protect against disease or enhance it?. Viruses 4:833–846.
Wongyanin P, Buranapraditkul S, Yoo D, Thanawongnuwech R, Roth JA, Suradhat S. Role of porcine reproductive and respiratory syndrome virus nucleocapsid protein in induction of interleukin-10 and regulatory T-lymphocytes (Treg). J Gen Virol 93:1236–1246.
Silva-Campa E, Mata-Haro V, Mateu E, Hernandez J. Porcine reproductive and respiratory syndrome virus induces CD4+ CD8+ CD25+ Foxp3+ regulatory T cells (Tregs). Virology 430:73–80.
Cecere TE, Meng XJ, Pelzer K, Todd SM, Beach NM, Ni YY, Leroith T. Co-infection of porcine dendritic cells with porcine circovirus type 2a (PCV2a) and genotype II porcine reproductive and respiratory syndrome virus (PRRSV) induces CD4+ CD25+ FoxP3+ T cells in vitro. Vet Microbiol 160:233–239.
Gomez-Laguna J, Rodriguez-Gomez IM, Barranco I, Pallares FJ, Salguero FJ, Carrasco L. Enhanced expression of TGFβ protein in lymphoid organs and lung, but not in serum, of pigs infected with a European field isolate of porcine reproductive and respiratory syndrome virus. Vet Microbiol 158:187–193.
Carossino M, Lee PA, Nam B, Skillman A, Shuck KM, Timoney PJ, Tsai Y, Ma L, Chang HG, Wang HT, Balasuriya UBR. Development and evaluation of a reverse transcription-insulated isothermal polymerase chain reaction (RT-iiPCR) assay for detection of equine arteritis virus in equine semen and tissue samples using the POCKIT system. J Virol Methods 234:7–15.
Pacheco JM, Smoliga GR, O'Donnell V, Brito BP, Stenfeldt C, Rodriguez LL, Arzt J. Persistent foot-and-mouth disease virus infection in the nasopharynx of cattle; tissue-specific distribution and local cytokine expression. PLoS One 10:e0125698.
Stenfeldt C, Pacheco JM, Smoliga GR, Bishop E, Pauszek SJ, Hartwig EJ, Rodriguez LL, Arzt J. Detection of foot-and-mouth disease virus RNA and capsid protein in lymphoid tissues of convalescent pigs does not indicate existence of a carrier state. Transbound Emerg Dis 63:152–164.
Prabhudas M, Bowdish D, Drickamer K, Febbraio M, Herz J, Kobzik L, Krieger M, Loike J, Means TK, Moestrup SK, Post S, Sawamura T, Silverstein S, Wang XY, El Khoury J. Standardizing scavenger receptor nomenclature. J Immunol 192:1997–2006.
Morgan AJ, Guillen C, Symon FA, Huynh TT, Berry MA, Entwisle JJ, Briskin M, Pavord ID, Wardlaw AJ. Expression of CXCR6 and its ligand CXCL16 in the lung in health and disease. Clin Exp Allergy 35:1572–1580.
Richardsen E, Ness N, Melbo-Jorgensen C, Johannesen C, Grindstad T, Nordbakken C, Al-Saad S, Andersen S, Donnem T, Nordby Y, Bremnes RM, Busund LT. The prognostic significance of CXCL16 and its receptor C-X-C chemokine receptor 6 in prostate cancer. Am J Pathol 185:2722–2730.
Nakayama T, Hieshima K, Izawa D, Tatsumi Y, Kanamaru A, Yoshie O. Cutting edge: profile of chemokine receptor expression on human plasma cells accounts for their efficient recruitment to target tissues. J Immunol 170:1136–1140.
Gunther C, Carballido-Perrig N, Kaesler S, Carballido JM, Biedermann T. CXCL16 and CXCR6 are upregulated in psoriasis and mediate cutaneous recruitment of human CD8+ T cells. J Investig Dermatol 132:626–634.
van der Voort R, van Lieshout AW, Toonen LW, Sloetjes AW, van den Berg WB, Figdor CG, Radstake TR, Adema GJ. Elevated CXCL16 expression by synovial macrophages recruits memory T cells into rheumatoid joints. Arthritis Rheum 52:1381–1391.
World Organisation for Animal Health (OIE). Equine viral arteritis, chapter 2.5.10. Manual of diagnostic tests and vaccines for terrestrial animals 7th ed, vol 2.
Gown AM, Goldstein LC, Barry TS, Kussick SJ, Kandalaft PL, Kim PM, Tse CC. High concordance between immunohistochemistry and fluorescence in situ hybridization testing for HER2 status in breast cancer requires a normalized IHC scoring system. Mod Pathol 21:1271–1277.
Boliar S, Chambers TM. A new strategy of immune evasion by influenza A virus: inhibition of monocyte differentiation into dendritic cells. Vet Immunol Immunopathol 136:201–210.
Yamate J, Yoshida H, Tsukamoto Y, Ide M, Kuwamura M, Ohashi F, Miyamoto T, Kotani T, Sakuma S, Takeya M. Distribution of cells immunopositive for AM-3K, a novel monoclonal antibody recognizing human macrophages, in normal and diseased tissues of dogs, cats, horses, cattle, pigs, and rabbits. Vet Pathol 37:168–176.
Tomokiyo R, Jinnouchi K, Honda M, Wada Y, Hanada N, Hiraoka T, Suzuki H, Kodama T, Takahashi K, Takeya M. Production, characterization, and interspecies reactivities of monoclonal antibodies against human class A macrophage scavenger receptors. Atherosclerosis 161:123–132.
Bohn W, Wiegers W, Beuttenmuller M, Traub P. Species-specific recognition patterns of monoclonal antibodies directed against vimentin. Exp Cell Res 201:1–7.
Yan B, Guo J, Lai W, Chen Y, Wang Z, Peng Y, Chang S. The multifaceted roles of ribosomal P complex in cancer. World J Surg Oncol 2025 Oct 21;23(1):388.
Durazo-Martínez K, Osorio FA, Delhon G, Hernández J, Vu HLX. New insights into the testicular tropism of porcine reproductive and respiratory syndrome virus. Microbiol Spectr 2025 Apr;13(4):e0296424.
Butler JE, Sinkora M, Wang G, Stepanova K, Li Y, Cai X. Perturbation of Thymocyte Development Underlies the PRRS Pandemic: A Testable Hypothesis. Front Immunol 2019;10:1077.