Development of replication-defective adenovirus serotype 5 containing the capsid and 3C protease coding regions of foot-and-mouth disease virus as a vaccine candidate

A recombinant replication-defective human adenovirus serotype 5 vector cont aining FMDV capsid, P1-2A, and viral 3C protease coding regions was constru cted. Two viral clones were isolated, Ad5-P12X3CWT, containing the wild-typ e (WT) 3C protease that processes capsid polyprotein precursor into mature capsid proteins, and Ad5-P12X3CMUT, containing a point mutation in the prot ease coding region that inhibits processing. In 293 cells infected with eit her virus, synthesis of the FMDV capsid polyprotein precursor occurred, but processing of the polyprotein into structural proteins VP0, VP3, and VP1 o ccurred only in 3CWT virus-infected cells. Immunoprecipitation with monospe cific and monoclonal antibodies indicates possible higher order structure f ormation in Ad5-P12X3CWT virus-infected cells. The viruses were used to eli cit immune responses in mice inoculated intramuscularly (im). Only virus co ntaining the 3CWT elicited a neutralizing antibody response. After boosting , this neutralizing antibody response increased. Swine inoculated im with A d5-P12X3CWT virus developed a neutralizing antibody response and were eithe r completely or partially protected from contract challenge with an animal directly inoculated with virulent FMDV. This adenovirus vector may be an ef ficient system for the delivery of FMDV cDNA into animals, leading to a hig h level of neutralizing antibody production and protection from FMDV challe nge. (C) 1999 Academic Press.