Proteome-wide screening of the European porcine reproductive and respiratory syndrome virus reveals a broad range of T cell antigen reactivity.
The porcine reproductive and respiratory syndrome virus (PRRSV) is a rapidly evolving and diversifying pathogen necessitating the development of improved vaccines. Immunity to PRRSV is not well understood although there are data suggesting that virus-specific T cell IFN-γ responses play an important role. We therefore aimed to better characterise the T cell response to genotype 1 (European) PRRSV by utilising a synthetic peptide library spanning the entire proteome and a small cohort of pigs rendered immune to PRRSV-1 Olot/91 by repeated experimental infection. Using an IFN-γ ELISpot assay as a read-out, we were able to identify 9 antigenic regions on 5 of the viral proteins and determine the corresponding responder T cell phenotype. The diversity of the IFN-γ response to PRRSV proteins suggests that antigenic regions are scattered throughout the proteome and no one single antigen dominates the T cell response. To address the identification of well-conserved T cell antigens, we subsequently screened groups of pigs infected with a closely related avirulent PRRSV-1 strain (Lelystad) and a divergent virulent subtype 3 strain (SU1-Bel). Whilst T cell responses from both groups were observed against many of the antigens identified in the first study, animals infected with the SU1-Bel strain showed the greatest response against peptides representing the non-structural protein 5. The proteome-wide peptide library screening method used here, as well as the antigens identified, warrant further evaluation in the context of next generation vaccine development.
Virology Department, Animal Health and Veterinary Laboratories Agency (AHVLA), Addlestone KT15 3NB, UK; Department of Microbial & Cellular Sciences, University of Surrey, Guildford GU2 7XH, UK.
Helen
H
Mokhtar
Institute of Virology and Immunology (IVI), Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Switzerland.
Melanie
M
Eck
Virology Department, Animal Health and Veterinary Laboratories Agency (AHVLA), Addlestone KT15 3NB, UK.
Sophie B
SB
Morgan
Department of Pathobiology, Institute of Immunology, University of Veterinary Medicine Vienna, Veterinaerplatz 1, Vienna A-1210, Austria.
Sabine E
SE
Essler
Virology Department, Animal Health and Veterinary Laboratories Agency (AHVLA), Addlestone KT15 3NB, UK.
Jean-Pierre
JP
Frossard
Institute of Virology and Immunology (IVI), Sensemattstrasse 293, CH-3147 Mittelhäusern, Switzerland.
Nicolas
N
Ruggli
Virology Department, Animal Health and Veterinary Laboratories Agency (AHVLA), Addlestone KT15 3NB, UK. Electronic address: simon.graham@ahvla.gsi.gov.uk.
Simon P
SP
Graham
D000818:Animals; D000956:Antigens, Viral / Q000276:immunology*; D058501:Enzyme-Linked Immunospot Assay; D007371:Interferon-gamma / Q000378:metabolism; D019316:Porcine respiratory and reproductive syndrome virus / Q000276:immunology*; D020543:Proteome / Q000276:immunology*; D013552:Swine; D013601:T-Lymphocytes / Q000276:immunology*; D014764:Viral Proteins / Q000276:immunology*
D000956:Antigens, Viral; D020543:Proteome; D014764:Viral Proteins; D007371:Interferon-gamma
Antigen identification; ELISpot assay; IFN-γ; Porcine; Porcine reproductive and respiratory syndrome virus; T cell