Induction of an antigen-specific immune response and partial protection of cattle against challenge infection with foot-and-mouth disease virus (FMDV) after lipopeptide vaccination with FMDV-specific B-cell epitopes

To evaluate the potential of chemically synthesized lipopeptides for vaccination against foot-and-mouth disease (FMD), seven lipopeptides containing the immunostimulating principle of bacterial lipoproteins and linear B-cell epitopes of FMDV strain O(1)Kaufbeuren (O(1)K) were used to immunize cattle (n=7). Animals were vaccinated once and 21 days after immunization animals were infected with the homologous virus. Four animals were protected. After vaccination, as well as after challenge infection, B- and T-cell responses were examined. Sera were tested for virus- and peptide-specific antibodies and showed after vaccination only a weak antibody response. After challenge infection, an increase in antibody titre was obvious but there was no correlation between antibody titre and protection. The reactivity of the cellular immune system was detected by analyses of PBMCs for virus- and peptide-specific T-lymphocytes. With regard to the virus-specific T-lymphocytes, a heterogeneous reactivity could be shown. No correlation between virus-specific T-cell proliferation and protection was found. Obvious was the fact that all protected animals showed after vaccination a strong T-cell response against at least one of the peptides used for immunization. These results suggest a correlation between the onset of an antigen-specific T-cell reaction and protection.