Submitted to: Virus Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/1/2003
Publication Date: 6/1/2003
Citation: WU, Q., MORAES, M.P., GRUBMAN, M.J. RECOMBINAT ADENOVIRUS CO-EXPRESSING CAPSID PROTEINS OF TWO SEROTYPES OF FOOT-AND-MOUTH DISESE VIRUS(FMDV): IN VITRO CHARACTERIZATION AND INDUCTION OF NEUTRALIZING ANTIBODIES AGAINST FMDV IN SWINE. VIRUS RESEARCH. V93(2):211-219, 2003. Interpretive Summary: Foot-and-mouth disease virus (FMDV) causes an economically devastating disease of cloven-hoofed animals. Vaccines produced by chemical inactivation of virus are available, but there are concerns about their safety because it has been demonstrated that disease outbreaks have been caused by improper inactivation and escape of infectious virus from vaccine manufacturing centers. In addition, it is difficult to distinguish serologically infected animals and animals vaccinated with chemically inactivated vaccine. A possible alternative approach to development of safe, effective FMD vaccines is to produce viral subunit vaccines, which do not contain infectious FMDV, and thus have a number of advantages over the current strategy. We have developed human adenovirus as an expression vector that contains a noninfectous portion of the FMDV genome and have demonstrated that this vector is able to induce a protective response in swine when challenged with virulent FMDV. FMDV consists of seven serotypes and infection with one serotype does not confer protection against another. Therefore, multivalent vaccine preparations have been used in vaccination programs. In this manuscript we have produced an adenovirus vector containing the viral subunits from two FMDV field strains, serotypes A24 Cruzeiro and 01 Campos. Swine inoculated with this bivalent vector developed an immune response against both FMDV serotypes.
Technical Abstract: Human adenovirus type 5 (Ad5) has been evaluated as a novel gene delivery vector for the development of live-viral vaccines for foot-and-mouth disease (FMD). In this study, we constructed an Ad5 vector co-expressing the capsid precursor proteins, P1, of FMD virus (FMDV) field strains A24 Cruzeiro and 01 Campos and examined the neutralizing antibody responses in swine after inoculation with the vector. To construct the Ad5 vector, a bicistronic expression cassette containing a cytomegalovirus promoter, the P1 coding sequence of FMDV A24, the internal ribosomal entry site (IRES) of FMDV A12, the P1 coding sequence of FMDV 01 Campos and the coding region of A12 3C protease was inserted into the E1 region of an E1/E3-deleted Ad5. The recombinant adenovirus, Ad5A24+01, was generated by transfection of 293 cells with full-length pAd5A24+01 recombinant plasmid DNA. The recombinant Ad5 co-expressed P1 of both A24 and 01 in infected 293 cells and P1 of both serotypes was processed to produce VP0, VP3 and VP1. We further demonstrated the formation of capsid protein complexes by co-precipitation of VP0, VP3, and VP1 with monoclonal antibodies against viral capsid proteins. Swine inoculated with Ad5A24+01 generated neutralizing antibodies against both A24 and 01. However, the overall neutralizing antibody response was considerably lower than that induced by a commercial FMD vaccine or a monovalent Ad5-A24 vaccine.