Identification of equine herpesvirus-1 antigens recognized by cytotoxic T lymphocytes

• Published in: Journal of general virology Vol. 84; no. 10; pp. 2625 - 2634
• Main Authors: Soboll, Gisela, Whalley, J. Millar, Koen, Mathew T, Allen, George P, Fraser, Darrilyn G, Macklin, Michael D, Swain, William F, Lunn, D. Paul
• Format: Journal Article
• Language: English
• Published: England Soc General Microbiol 01-10-2003
• Subjects: Animals; antigens; Antigens, Viral - genetics; Antigens, Viral - immunology; Cells, Cultured; Dendritic Cells - immunology; Dendritic Cells - virology; Equine herpesvirus 1; Herpesviridae Infections - immunology; Herpesviridae Infections - veterinary; Herpesviridae Infections - virology; Herpesvirus 1, Equid - genetics; Herpesvirus 1, Equid - immunology; Horse Diseases - immunology; Horse Diseases - virology; Horses; Lymphocyte Activation; T-Lymphocytes, Cytotoxic - immunology; Transfection; Viral Proteins - genetics; Viral Proteins - immunology
• ISSN: 0022-1317; 1465-2099
• DOI: 10.1099/vir.0.19268-0

1 Department of Medical Sciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI 53706, USA
2 Department of Biological Sciences, Macquarie University, Sydney, Australia
3 Department of Veterinary Sciences, University of Kentucky, Lexington, KY 40546, USA
4 Department of Veterinary Microbiology and Immunology, Washington State University, Pullman, WA 99164, USA
5 PowderJect Vaccines Inc., 585 Science Drive, Suite C, Madison, WI 53711, USA
Correspondence Paul Lunn lunnp{at}svm.vetmed.wisc.edu
Equine herpesvirus-1 (EHV-1) causes serious disease in horses throughout the world, despite the frequent use of vaccines. CTLs are thought to be critical for protection from primary and reactivating latent EHV-1 infections. However, the antigen-specificity of EHV-1-specific CTLs is unknown. The aim of this study was to identify EHV-1 genes that encode proteins containing CTL epitopes and to determine their MHC I (or ELA-A in the horse) restriction. Equine dendritic cells, transfected with a series of EHV-1 genes, were used to stimulate autologous CTL precursor populations derived from previously infected horses. Cytotoxicity was subsequently measured against EHV-1-infected PWM lymphoblast targets. Dendritic cells were infected with EHV-1 (positive control) or transfected with plasmids encoding the gB, gC, gD, gE, gH, gI, gL, immediate-early (IE) or early protein of EHV-1 using the PowderJect XR-1 research device. Dendritic cells transfected with the IE gene induced CTL responses in four of six ponies. All four of these ponies shared a common ELA-A3.1 haplotype. Dendritic cells transfected with gC, gD, gI and gL glycoproteins induced CTLs in individual ponies. The cytotoxic activity was ELA-A-restricted, as heterologous targets from ELA-A mismatched ponies were not killed and an MHC I blocking antibody reduced EHV-1-specific killing. This is the first identification of an EHV-1 protein containing ELA-A-restricted CTL epitopes. This assay can now be used to study CTL specificity for EHV-1 proteins in horses with a broad range of ELA-A haplotypes, with the goal of developing a multi-epitope EHV-1 vaccine.