Importance of ovine cytotoxic T cells in protection against bluetongue virus infection.

In sheep, bluetongue virus (BTV) was shown to induce anti-BTV cytotoxic T lymphocytes (CTL) and their effect to be maximal around 14 days post inoculation (p.i.) of virus. Using cellular adoptive transfer techniques in monozygotic sheep, such cells were shown to partially protect animals from BTV challenge. A short-lived cross-protective mechanism was identified involving thoracic duct lymphocytes (TDL) and nonneutralising antibody. These observations suggest that T lymphocytes play an important role in protection against BTV and that current vaccine design based on in vitro serological typing of BTV can be improved.