Cloned bovine cytolytic T cells recognize bovine herpes virus-1 in a genetically restricted, antigen-specific manner

The inability to demonstrate bovine herpes virus-1 (BHV-1)-specific lymphocyte responses from BHV-1-infected cattle has been a major difficulty in confirming the importance of cellular effector mechanisms during BHV-1 infection. We have examined the capacity of bovine cytolytic T-cell clones to lyse BHV-1-infected, concanavalin A-stimulated blast cells. Cytolysis was as high as 58% at an effector to target (E:T) ratio of 1:1. All cytolytic T-cell clones produced were genetically restricted in killing cells of the autologous genotype. Cytotoxic T-lymphocyte (CTL) clones were specific for BHV-1 but not related herpes viruses, i.e. BHV-2 and pseudorabies virus. These results provide evidence that cytolytic T lymphocytes have an antigen-specific role in the immune response of cattle against BHV-1, and that CTL may serve as effector cells in the identification of glycoproteins useful in recombinant vaccine preparation since only determinants of BHV-1 were recognized.