T-CELL RESPONSES TO BPV-4 E7 DURING INFECTION AND MAPPING OF T-CELL EPITOPES

Vaccination of cattle with the recombinant E7 protein of bovine papill omavirus type 4 (BPV-4) prior to BPV-LF infection has been shown to re tard development of papillomas and accelerate their regression. To und erstand the mechanism of regression we have measured proliferation of peripheral blood mononuclear cells (PBM) to E7 in vitro during the cou rse of BPV-4 infection in both vaccinated and nonvaccinated cattle. In vaccinated cattle, T cells specific for E7 could be detected al high levels shortly after challenge, whereas in nonvaccinated cattle low re sponses of E7-specific T cells could be detected in only a few animals at the late stages of papilloma development. Using short overlapping synthetic peptides corresponding to the E7 protein, three T cell epito pes have been identified. T1 (aa 31-59) was immunodominant and T2 (aa 70-88) and T3 (aa 21-40) were minor epitopes. (C) 1995 Academic Press, Inc.