Equine herpesvirus-1 infection induces IFN-γ production by equine T lymphocyte subsets

In vitro restimulation of PBMC with EHV-1 induced IFN-γ production by a significantly higher percentage of total (CD5+) T lymphocytes, and CD4+ and CD8+ T lymphocyte subsets among post-EHV-1 infection PBMC samples compared to pre-infection samples. This response was associated with an increase in virus-specific CTL activity, a critical immune effector for the control of EHV-1 infection and disease. No significant increase in IFN-γ production by B lymphocytes was observed. These data demonstrate that EHV-1 challenge infection of ponies results in increased production of IFN-γ by virus-specific T lymphocytes, and that this response can be quantitated using flow cytometry.