Equine interferon gamma synthesis in lymphocytes after in vivo infection and in vitro stimulation with EHV-1

• DOI: 10.1016/j.vaccine.2005.03.048
• Publication Date: 2005-05-15T05:27:36Z
• Authors: R. Paillot; J.M. Daly; V. Juillard; J.M. Minke; D. Hannant; J.H. Kydd
• Keywords: Cryopreservation; Male; Age Factors; Herpesviridae Infections; 04 agricultural and veterinary sciences; 3. Good health; 0403 veterinary science; Interferon-gamma; Leukocytes, Mononuclear; Animals; Horse Diseases; Horses; Lymphocytes; Herpesvirus 1, Equid; T-Lymphocytes, Cytotoxic

Equine cytotoxic T lymphocyte (CTL) responses to equine herpesvirus-1 (EHV-1) are well characterised but little is known about the cytokine response after infection or vaccination. EHV-1 is common in horses and infects lymphocytes in vivo. This virus was used as a model to measure the synthesis of interferon gamma (IFN-gamma) by equine peripheral blood mononuclear cells (PBMC) after in vivo infection and/or in vitro stimulation with EHV-1. Both flow cytometry and ELISPOT assays were used to quantify equine IFN-gamma using a mouse anti-bovine IFN-gamma monoclonal antibody (clone CC302; shown to cross-react with recombinant equine IFN-gamma) and a rabbit anti-canine IFN-gamma polyclonal antibody. The percentage of PBMC synthesising IFN-gamma after in vitro stimulation with EHV-1 increased with age. In yearlings infected experimentally with EHV-1, PBMC showed two peaks of IFN-gamma synthesis, 11 and 56 days after infection. The IFN-gamma synthesis was principally associated with CD8(+) cells. The patterns of IFN-gamma synthesis detected by intracellular IFN-gamma staining or ELISPOT were compared with CTL data and shown to be similar. These methods were also applied successfully to frozen samples of PBMC. Measurement of equine IFN-gamma using these simple techniques can now be applied to future studies on protective cellular immune responses following virus infection and/or vaccination of horses.