Rapid Engineering of Foot-and-Mouth Disease Vaccine and Challenge Viruses.

There are seven antigenically distinct serotypes of foot-and-mouth disease virus (FMDV), each of which has intratypic variants. In the present study, we have developed methods to efficiently generate promising vaccines against seven serotypes or subtypes. The capsid-encoding gene (P1) of the vaccine strain O1/Manisa/Turkey/69 was replaced with the amplified or synthetic genes from the O, A, Asia1, C, SAT1, SAT2, and SAT3 serotypes. Viruses of the seven serotype were rescued successfully. Each chimeric FMDV with a replacement of P1 showed serotype-specific antigenicity and varied in terms of pathogenesis in pigs and mice. Vaccination of pigs with an experimental trivalent vaccine containing the inactivated recombinants based on the main serotypes O, A, and Asia1 effectively protected them from virus challenge. This technology could be a potential strategy for a customized vaccine with challenge tools to protect against epizootic disease caused by specific serotypes or subtypes of FMDV.IMPORTANCE Foot-and-mouth disease (FMD) virus (FMDV) causes significant economic losses. For vaccine preparation, the selection of vaccine strains was complicated by high antigenic variation. In the present study, we suggested an effective strategy to rapidly prepare and evaluate mass-produced customized vaccines against epidemic strains. The P1 gene encoding the structural proteins of the well-known vaccine virus was replaced by the synthetic or amplified genes of viruses of seven representative serotypes. These chimeric viruses generally replicated readily in cell culture and had a particle size similar to that of the original vaccine strain. Their antigenicity mirrored that of the original serotype from which their P1 gene was derived. Animal infection experiments revealed that the recombinants varied in terms of pathogenicity. This strategy will be a useful tool for rapidly generating customized FMD vaccines or challenge viruses for all serotypes, especially for FMD-free countries, which have prohibited the import of FMDVs.

Construction of stabilized and tagged foot-and-mouth disease virus.

Foot-and-mouth disease (FMD) is a highly contagious and economically devastating disease that affects cloven-hoofed animals worldwide. Construction and purification of stable antigen for vaccine are necessary but technically difficult and laborious. Here, we have tried to investigate an alternative method by inserting a hexa-histidine tag (6xHIS) in the VP1 C-terminal for easy purification and replacing two amino acids of VP1/VP2 to enhance the stability of the capsid of the FMD virus (FMDV) Asia1/MOG/05. In addition, infectious 6xHIS-tagged stable (S/T) FMDVs were maintained under acidic conditions (pH 6.0) and were readily purified from small-scale cultures using a commercial metal-affinity column. The groups vaccinated with the S/T FMDV antigen showed complete protection comparing to low survival rate in the group vaccinated with non-S/T FMDV against lethal challenge with Asia1 Shamir in mice. Therefore, the present findings indicate that the stabilized and tagged antigen offers an alternative to using the current methods for antigen purification and enhancement of stability and has potential for the development of a new FMD vaccine.

The Incidence and Risk Factors for Lumbar or Sciatic Scoliosis in Lumbar Disc Herniation and the Outcomes after Percutaneous Endoscopic Discectomy.

BACKGROUND: Some patients with lumbar herniated intervertebral disc disease (HIVD) suffer from both pain and lateral shift or trunk list. In addition to pain, patients have concerns regarding whether trunk list is reversible. Surgical treatment is performed when pain is intractable to conservative management, but a reversal of trunk list is an incidental outcome. Percutaneous lumbar endoscopic discectomy (PELD) is one of the surgical treatment options for lumbar HIVD, but no results concerning its effect on trunk list have been reported. OBJECTIVES: The objectives of the present study were to determine the incidence of, and risk factors for, trunk list scoliosis or lateral shift and to report the outcomes of trunk list after PELD. STUDY DESIGN: Retrospective case study. IRB No. H 1111-025-384 SETTING; University medical Center, Seoul, Korea. METHODS: We selected 164 patients who were less than 60 years old, complained of unilateral leg pain, and underwent PELD. We measured the maximum trunk shift from the central sacral vertical line (CSVL-max) on preoperative whole spine radiographs and classified trunk list as CSVL-max ≥ 10 mm. CSVL-max was measured on serial radiographs taken at one, 3, 6, and 12 months postoperatively in patients with trunk list. RESULTS: Twenty-nine patients (17.9%) had trunk list (M:F=10:19; mean age, 37.1 ± 11.24 years). Female gender (OR 4.28; 95% CI, 1.49-12.3) and HIVD at L4-5 (OR 5.6; 95% CI, 1.8-16.7) were risk factors for trunk list. Trunk list was normalized (CSVL-max < 10 mm) in 15 (52%) patients after PELD, and the median time for normalization was 3-6 months. Prognostic factors for the recovery of trunk list were not identified. LIMITATIONS: Selection bias should be considered in interpreting these results. CONCLUSION: Trunk list, scoliosis or lateral shift, was observed in 18% of the patients at the time of surgery. Female gender and L4-5 disc herniation were risk factors for trunk list. Trunk list was reversible in more than 50% of patients within 6 months of PELD.

Antigenic properties and virulence of foot-and-mouth disease virus rescued from full-length cDNA clone of serotype O, typical vaccine strain.

We cloned the full-length cDNA of O Manisa, the virus for vaccinating against foot-and-mouth disease. The antigenic properties of the virus recovered from the cDNA were similar to those of the parental virus. Pathogenesis did not appear in the pigs, dairy goats or suckling mice, but neutralizing antibodies were raised 5-6 days after the virus challenge. The utilization of O Manisa as a safe vaccine strain will increase if recombinant viruses can be manipulated by inserting or removing a marker gene for differential serology or replacing the protective gene from another serotype.

Genetic and immunologic relationships between vaccine and field strains for vaccine selection of type A foot-and-mouth disease virus circulating in East Asia.

Of the seven known serotypes of foot-and-mouth disease virus (FMDV), type A has the most diverse variations. Genetic variations also occur frequently at VP1, VP2, VP3, and VP4 because these proteins constitute the viral capsid. The structural proteins of FMDV, which are closely related to immunologic correlations, are the most easily analyzed because they have highly accessible information. In this study we analyzed the type A vaccine viruses by alignment of available sequences in order to find appropriate vaccine strains. The matching rate of ASIA topotype-specific sites (20 amino acids) located on the viral surface, which are mainly VP1 and VP2, was highly related to immunologic reactivity. Among the available vaccines analyzed in this study, we suggest that A Malaysia 97 could be used as a vaccine virus as it has the highest genetic similarity and immunologic aspects to field strains originating in East Asia.

Enhanced immune responses of foot-and-mouth disease vaccine using new oil/gel adjuvant mixtures in pigs and goats.

The immunity and protective capability produced by vaccines can vary remarkably according to the kinds of adjuvants being used. In the case of foot-and-mouth disease (FMD) vaccines in pigs, only oil-adjuvant vaccines have been used, and these tend to show lower immunity in pigs than in cattle. New adjuvants for these vaccines are therefore needed. We made different experimental FMD vaccines using new adjuvants (ISA 201, Carbigen, Emulsigen-D) and well-known adjuvants (ISA 206, aluminum hydroxide gel) and then conducted tests to compare the enhancement in pig immunity. More effective immune responses and protection against challenge were observed with the new adjuvants Emulsigen-D and ISA 201 compared to existing adjuvants. In the case of dairy goats, a mixture of Emulsigen-D and aluminum hydroxide gel produced rapid neutralizing antibody responses that were similar to results from tests conducted with pigs.

Protection to homologous and heterologous challenge in pigs immunized with vaccine against foot-and-mouth disease type O caused an epidemic in East Asia during 2010/2011.

Foot-and-mouth disease (FMD) is a highly contagious infectious disease, and the use of vaccines is known to be effective for its prevention. In 2010/2011, there was an epidemic of the South East Asia (SEA) topotype in East Asian countries. We adapted the SEA topotype virus isolated in November 2010 in Korea in cells to analyze the characteristics of the virus and evaluate its possibility as a vaccine. After cell culture adaptation, the FMD virus particle 146S was purified to develop an inactivated oil vaccine for SEA or other topotypes. To measure its immunogenicity, pigs were inoculated with the experimental vaccine at different concentrations of the antigen. The results indicated that the groups immunized with at least 7.5 µg antigen were protected from homologous challenge. The immunized pigs were also protected against heterologous virus (ME-SA topotype) challenge. The genetic variations between the two field isolates and the adapted vaccine strains were identified in six amino acids by complete genome sequencing.