Protection of guinea pigs and swine by a recombinant adenovirus expressing O serotype of foot-and-mouth disease virus whole capsid and 3C protease

Exploring Hollow Mesoporous Silica Nanoparticles as a Nanocarrier in the Delivery of Foot-And-Mouth Disease Virus-like Particle Vaccines

Virus-like particle (VLP) vaccine is considered to be the most promising candidate alternative to the traditional inactivated vaccine for foot-and-mouth disease (FMD). To elicit a desired immune response, hollow mesoporous silica nanoparticles (HMSNs) have been synthesized and utilized as a nanocarrier for FMD VLP vaccine delivery. The as-prepared HMSNs displayed a relatively small particle size (∼260 nm), large cavity (∼150 nm), and thin wall (∼55 nm). The inherent structural superiorities make them ideal nanocarriers for the FMD VLP vaccine, which exhibited good biocompatibility, great protein-loading capacity, high antibody-response level, and protective efficiency, even comparable to commercial adjuvant ISA 206. All the results suggested that HMSNs may be a valid nanocarrier in VLP-based vaccines.

Foot-and-mouth disease vaccines: recent updates and future perspectives

Foot-and-mouth disease (FMD) is a major worldwide viral disease in animals, affecting the national and international trade of livestock and animal products and leading to high economic losses and social consequences. Effective control measures of FMD involve prevention through vaccination with inactivated vaccines. These inactivated vaccines, unfortunately, require short-term protection and cold-chain and high-containment facilities. Major advances and pursuit of hot topics in vaccinology and vectorology are ongoing, involving peptide vaccines, DNA vaccines, live vector vaccines, and novel attenuated vaccines. DIVA capability and marker vaccines are very important in differentiating infected animals from vaccinated animals. This review focuses on updating the research progress of these novel vaccines, summarizing their merits and including ideas for improvement.

A canine adenovirus type 2 vaccine vector confers protection against foot-and-mouth disease in guinea pigs

Vaccination is a key element in the control of foot-and-mouth disease (FMD). The majority of the antigenic sites that induce protective immune responses are localized on the FMD virus (FMDV) capsid that is formed by four virus-encoded structural proteins, VP1 to VP4. In the present study, recombinant canine adenovirus type 2 (CAV2)-based FMD vaccines, Cav-P1/3C R° and Cav-VP1 R°, respectively expressing the structural P1 precursor protein along with the non-structural 3C protein or expressing the structural VP1 protein of the FMDV strain O/FRA/1/2001, were evaluated as novel vaccines against FMD. A strong humoral immune response was elicited in guinea pigs (GP) following immunization with Cav-P1/3C R°, while administration of Cav-VP1 R° did not induce a satisfying antibody response in GP or mice. GP were then used as an experimental model for the determination of the protection afforded by the Cav-P1/3C R° vaccine against challenge with the FMDV strain O₁ Manisa/Turkey/1969. The Cav-P1/3C R° vaccine protected GP from generalized FMD to a similar extent as a high potency double-oil emulsion O₁ Manisa vaccine. The results of the present study show that CAV2-based vector vaccines can express immunogenic FMDV antigens and offer protection against generalized FMD in GP. This suggest that Cav-P1/3C R° FMDV vaccine may protect natural host species from FMD. In combination with an appropriate diagnostic test, the Cav-P1/3C R° FMDV vaccine may also serve as a marker vaccine to differentiate vaccinated from infected animals.

Adenovirus-vectored foot-and-mouth disease vaccine confers early and full protection against FMDV O1 Manisa in swine

A human adenovirus (Ad5) vectored foot-and-mouth disease virus (FMDV) O1-Manisa subunit vaccine (Ad5-O1Man) was engineered to deliver FMDV O1-Manisa capsid and capsid-processing proteins. Swine inoculated with Ad5-O1Man developed an FMDV-specific humoral response as compared to animals inoculated with an empty Ad5-vector. Vaccinated animals were completely protected against homologous challenge at 7 or 21 days post-vaccination. Potency studies exhibited a PD50 of about 10⁷ pfu/animal while a dose of 4×10⁷pfu/animal fully protected swine against FMDV intradermal challenge. In-vitro cross-neutralization analysis distinctly predicted that swine vaccinated with Ad5-O1Man would be protected against challenge with homologous FMDV O1Man Middle East-South Asia (ME-SA) topotype and also against recent outbreak strains of Mya-98 South East Asia (SEA) lineage including O1-UK-2001 and O1-South Korea-2010. These results indicate that recombinant Ad5-O1Man is an effective, safe and cross-reacting vaccine that could potentially be used preventively and in outbreak situations, to control FMDV O Mya-98 lineage in swine.

Construction and characterization of recombinant human adenovirus type 5 expressing foot-and-mouth disease virus capsid proteins of Indian vaccine strain, O/IND/R2/75

AIM

Generation of recombinant human adenovirus type 5 expressing foot-and-mouth disease virus (FMDV) capsid protein genes along with full-length 2B, 3B and 3C(pro) and its characterization.

MATERIALS AND METHODS

FMD viral RNA isolation, cDNA synthesis, and polymerase chain reaction were performed to synthesize expression cassettes (P1-2AB3BC(wt) and P1-2AB3BC(m)) followed by cloning in pShuttle-CMV vector. Chemically competent BJ5183-AD-1 cells were transformed with the recombinant pShuttle-CMV to produce recombinant adenoviral plasmids. HEK-293 cells were transfected with the recombinant adenoviral plasmids to generate recombinant adenoviruses (hAd5/P1-2AB3BC(wt) and hAd5/P1-2AB3BC(m)). Expression of the target proteins was analyzed by sandwich ELISA and indirect immunofluorescence assay. The recombinant adenoviruses were purified and concentrated by CsCl density gradient ultracentrifugation. Growth kinetics and thermostability of the recombinant adenoviruses were compared with that of non-recombinant replication-defective adenovirus (dAd5).

RESULTS

The recombinant adenoviruses containing capsid protein genes of the FMDV O/IND/R2/75 were generated and amplified in HEK-293 cells. The titer of the recombinant adenoviruses was approximately 10(8), 10(9.5) and 10(11) TCID50/ml in supernatant media, cell lysate and CsCl purified preparation, respectively. Expression of the FMDV capsid protein was detectable in sandwich ELISA and confirmed by immunofluorescence assay. Growth kinetics of the recombinant adenoviruses did not reveal a significant difference when compared with that of dAd5. A decrement of up to 10-fold at 4°C and 21-fold at 37°C was recorded in the virus titers during 60 h incubation period and found to be statistically significant (p<0.01).

CONCLUSION

Recombinant adenoviruses expressing capsid proteins of the FMDV O/IND/R2/75 were constructed and produced in high titers. In vitro expression of the target proteins in the adenovirus vector system was detected by sandwich ELISA and immunofluorescence assay.

Three-dimensional structure of foot-and-mouth disease virus and its biological functions

Foot-and-mouth disease (FMD), an acute, violent, infectious disease of cloven-hoofed animals, remains widespread in most parts of the world. It can lead to a major plague of livestock and an economical catastrophe. Structural studies of FMD virus (FMDV) have greatly contributed to our understanding of the virus life cycle and provided new horizons for the control and eradication of FMDV. To examine host-FMDV interactions and viral pathogenesis from a structural perspective, the structures of viral structural and non-structural proteins are reviewed in the context of their relevance for virus assembly and dissociation, formation of capsid-like particles and virus-receptor complexes, and viral penetration and uncoating. Moreover, possibilities for devising novel antiviral treatments are discussed.

Development of porcine respiratory and reproductive syndrome virus replicon vector for foot-and-mouth disease vaccine

PURPOSE

Foot-and-mouth disease (FMD) is an economically important global animal disease. To control FMD virus (FMDV) outbreaks, a lot of different novel approaches have been attempted. In this study, we proposed a novel porcine reproductive and respiratory syndrome virus (PRRSV) as a replicon vector to express FMDV structural protein.

MATERIALS AND METHODS

PRRSV infectious clone (PRRSVK418DM) was used to develop an expression vector through the reverse genetic manipulation of PRRSV; FMDVP12A3C gene of serotype O was synthesized and used for an antigen. MARC-145 cells (African green monkey kidney epithelial cell line) were used for electroporation mediated transfection. The transfection or the expression of P12A3C and N protein of PRRSV was analyzed by either replicon containing PRRSV alone or by co-infection of helper PRRSV.

RESULTS

We constructed PRRSVK418DM replicon vector containing FMDVP12A3C, and genome sequences were confirmed by subsequent sequence analysis. In vitro expression of P12A3C and PRRSV N protein was confirmed by immunofluorescence antibody assay using antibodies specific for PRRSV N protein (anti-PRRSV N MAb), FMDV-VP1 (anti-VP1 MAb).

CONCLUSION

The results indicate that PRRSV replicon vector can be a promising novel vector system to control FMDV and useful for vaccine development in the future.

Foot-and-mouth disease virus-like particles produced by a SUMO fusion protein system in Escherichia coli induce potent protective immune responses in guinea pigs, swine and cattle

Foot-and-mouth disease virus (FMDV) causes a highly contagious infection in cloven-hoofed animals. The format of FMD virus-like particles (VLP) as a non-replicating particulate vaccine candidate is a promising alternative to conventional inactivated FMDV vaccines. In this study, we explored a prokaryotic system to express and assemble the FMD VLP and validated the potential of VLP as an FMDV vaccine candidate. VLP composed entirely of FMDV (Asia1/Jiangsu/China/2005) capsid proteins (VP0, VP1 and VP3) were simultaneously produced as SUMO fusion proteins by an improved SUMO fusion protein system in E. coli. Proteolytic removal of the SUMO moiety from the fusion proteins resulted in the assembly of VLP with size and shape resembling the authentic FMDV. Immunization of guinea pigs, swine and cattle with FMD VLP by intramuscular inoculation stimulated the FMDV-specific antibody response, neutralizing antibody response, T-cell proliferation response and secretion of cytokine IFN-γ. In addition, immunization with one dose of the VLP resulted in complete protection of these animals from homologous FMDV challenge. The 50% protection dose (PD₅₀) of FMD VLP in cattle is up to 6.34. These results suggest that FMD VLP expressed in E. coli are an effective vaccine in guinea pigs, swine and cattle and support further development of these VLP as a vaccine candidate for protection against FMDV.

Adenovirus-vectored type Asia1 foot-and-mouth disease virus (FMDV) capsid proteins as a vehicle to display a conserved, neutralising epitope of type O FMDV

The objective of this study was to explore the immunogenicity of an adenovirus construction expressing a type O foot and mouth disease virus neutralising epitope (8E8) in the context of heterologous capsid proteins. Adenoviruses expressing four chimeric type Asia1 FMDV capsid proteins were constructed by inserting the type O FMDV 8E8 epitope into the G-H loop from the type Asia1 VP1 at amino acid residues 139/140, 150/151, 134/140 or at both 139/140 and 150/151. These recombinant proteins were recognised by antibodies against the type O 8E8 epitope and type Asia1 FMDV. When inoculated in mice, all of the recombinant chimeric capsid proteins for each single epitope insertion induced the production of anti-type O FMDV neutralising antibodies. The recombinant chimeric capsid proteins with a foreign insertion at position 139/140 or 150/151 induced high levels of anti-type Asia1 FMDV neutralising antibodies as the recombinant type Asia1 capsid proteins without any foreign epitope, suggesting that the foreign insertion did not affect the immunogenicity of the type Asia1 FMDV capsid proteins. This study suggests that a foreign epitope displayed on the surface of the FMDV capsid proteins could induce an epitope-specific response. Therefore, the adenovirus-vectored FMDV capsid proteins could be used as a vehicle for the development of an epitope-based vaccine.

Research in advance for FMD novel vaccines

Foot-and-Mouth Disease (FMD), as a major global animal disease, affects millions of animals worldwide and remains the main sanitary barrier to the international and national trade of animals and animal products. Inactivated vaccination is the most effective measure for prevention of FMD at present, but fail to induce long-term protection and content new requires for production of FMD vaccines. As a number of Researchers hope to obtain satisfactory novel vaccines by new bio-technology, novel vaccines have been studied for more than thirty years. Here reviews the latest research progress of new vaccines, summarizes some importance and raises several suggestions for the future of FMD vaccine.

A pseudotype baculovirus expressing the capsid protein of foot-and-mouth disease virus and a T-cell immunogen shows enhanced immunogenicity in mice

Background

Foot-and-mouth disease (FMD) is a highly contagious disease of livestock which causes severe economic loss in cloven-hoofed animals. Vaccination is still a major strategy in developing countries to control FMD. Currently, inactivated vaccine of FMDV has been used in many countries with limited success and safety concerns. Development of a novel effective vaccine is must.

Methods

In the present study, two recombinant pseudotype baculoviruses, one expressing the capsid of foot-and-mouth disease virus (FMDV) under the control of a cytomegalovirus immediate early enhancer/promoter (CMV-IE), and the other the caspid plus a T-cell immunogen coding region under a CAG promoter were constructed, and their expression was characterized in mammalian cells. In addition, their immunogenicity in a mouse model was investigated. The humoral and cell-mediated immune responses induced by pseudotype baculovirus were compared with those of inactivated vaccine.

Results

Indirect immunofluorescence assay (IFA) and indirect sandwich-ELISA (IS-ELISA) showed both recombinant baculoviruses (with or without T-cell epitopes) were transduced efficiently and expressed target proteins in BHK-21 cells. In mice, intramuscular inoculation of recombinants with 1 × 10⁹ or 1 × 10¹⁰ PFU/mouse induced the production of FMDV-specific neutralizing antibodies and gamma interferon (IFN-γ). Furthermore, recombinant baculovirus with T-cell epitopes had better immunogenicity than the recombinant without T-cell epitopes as demonstrated by significantly enhanced IFN-γ production (P < 0.01) and higher neutralizing antibody titer (P < 0.05). Although the inactivated vaccine produced the highest titer of neutralizing antibodies, a lower IFN-γ expression was observed compared to the two recombinant pseudotype baculoviruses.

Conclusions

These results indicate that pseudotype baculovirus-mediated gene delivery could be a alternative strategy to develop a new generation of vaccines against FMDV infection.

Adenovirus serotype 5-vectored foot-and-mouth disease subunit vaccines: the first decade

The results of the first decade of the development of a replication-defective human adenovirus serotype 5 (Ad5) containing the capsid- and 3C protease-coding regions of foot-and-mouth disease (FMD) virus as a vaccine candidate are presented. In proof-of-concept studies, it was demonstrated that a single inoculation with this vaccine vector containing the capsid of FMD virus A24 Cruzeiro protected both swine and cattle following homologous challenge by direct inoculation 1 week postvaccination. We have expanded these studies in cattle with larger numbers of animals and by testing the vaccine in direct-contact challenge studies, including its ability to prevent FMD virus shedding and transmission. Furthermore, we have developed manufacturing protocols to allow the scalable production of these FMD molecular vaccine products for US Department of Agriculture licensure approval and availability for inclusion in the US National Veterinary Stockpile. We have also constructed and initiated cattle efficacy testing of Ad5 vectors containing the capsid-coding regions from other FMD virus serotypes and subtypes, as well as initiated studies to improve FMD molecular vaccine potency.