Evidence of partial protection against foot-and-mouth disease in cattle immunized with a recombinant adenovirus vector expressing the precursor polypeptide (P1) of foot-and-mouth disease virus capsid proteins

A recombinant live vector vaccine was produced by insertion of cDNA encodin g the structural proteins (P1) of foot-and-mouth disease virus (FMDV) into a replication-competent human adenovirus type 5 vaccine strain (Ad5 wt). Gr oups of cattle (n = 3) were immunized twice, by the subcutaneous and/or int ranasal routes, with either the Ad5 wt vaccine or with the recombinant FMDV Ad5-P1 vaccine. All animals were challenged by intranasal instillation of FMDV 4 weeks after the second immunizations. In the absence of a detectable antibody response to FMDV, significant protection against viral challenge was seen in all of the animals immunized twice by the subcutaneous route wi th the recombinant vaccine. The observed partial protection against clinica l disease was not associated with a reduction in titre of persistent FMDV i nfections in the oropharynx of challenged cattle.