Abstract:
The ability of a DNA vaccine to elicit an immune response in a horse was evaluated. The outer capsid
protein VP2 of African horsesickness virus is known to elicit protective immunity in horses. Reverse
transcribed DNA of the gene encoding VP2 was placed under the transcriptional control of the
cytomegalovirus immediate-early enhancer/promoter and was injected on several occasions intramuscularly
into a horse. Low antibody levels could be detected by ELISA. Antibodies directed against
VP2 alone were shown by Western blot while low levels of neutralizing antibodies were detected by
a 50% plaque reduction assay. In contrast to a relatively poor humoral response, a significant lymphoproliferative
response in the presence of whole virus proteins, as well as a cytotoxic cellular reaction
against virus-infected syngeneic target cells was shown.
