Equine herpesvirus-1-specific interferon gamma (IFNgamma) synthesis by peripheral blood mononuclear cells in thoroughbred horses.

The research article describes an assay that measures Equine Herpesvirus-1 (EHV-1) specific immune responses in Thoroughbred horses, and explores its potential association with factors such as age, gender, living conditions, and vaccination history.

Research Objective

• The primary objective of the study was to quantify the frequency of EHV-1 specific interferon gamma (IFNgamma) synthesising peripheral blood mononuclear cells (PBMC) in a Thoroughbred horse population.
• The researchers also aimed to investigate the potential relationship of this frequency with certain variables including age, gender, premises (stud farms or training yards), and history of vaccination or field infection with EHV-1.

Research Methods

• Lymphocytes from a sample of 200 Thoroughbred horses were stimulated with EHV-1 under laboratory conditions.
• The researchers then detected IFNgamma (an indicator of cellular immunity) using a monoclonal antibody and a method called indirect immunofluorescence.
• The percentage of positive cells was then counted using a process known as flow cytometric analysis.
• Statistical analysis was then conducted to evaluate and compare the results among different groups.

Research Findings

• The study found that older horses (more than 5 years old) had a significantly higher frequency of IFNgamma+ PBMCs than younger ones (2-4 years old).
• The researchers also found higher frequencies in female horses compared to males, as well as in horses located on stud farms compared to those in training yards.
• Horses that had been vaccinated at two years old with inactivated virus also showed a higher frequency of IFNgamma+ PBMCs compared to those that had not been vaccinated.
• However, the researchers caution that age strongly influences all these associations and thus should be considered when interpreting the results.
• The study also highlights that mares which were exposed to a field infection with EHV-1 had higher frequencies of IFNgamma+ PBMC than other vaccinated horses.

Conclusion

• Overall, the researchers concluded that the frequency of EHV-1 specific lymphocytes in Thoroughbred horses producing IFNgamma was widely varied but lowest in young unvaccinated horses.
• The research also suggests that this frequency may be associated with susceptibility to EHV-1 infection in this particular population.
• Implying that this simple technique could potentially be leveraged to effectively monitor vaccine antigenicity and their capacity to stimulate cellular immunity.