Whole-genome sequencing of foot-and-mouth disease virus serotype O/PanAsia-2/QOM-15 and comparison of its VP1-encoding region with two vaccine strains.

Despite widespread vaccination against foot-and-mouth disease, many outbreaks still occur in endemic areas. We attempted to determine the genetic and antigenic properties of the O/PanAsia-2/QOM-15 foot-and-mouth disease virus new vaccine strain. Thus, whole-genome sequencing was used to identify vulnerable pinpoint sites across the genome. The VP1 sequence (1D gene) of the O/PanAsia-2/QOM-15 viral genome was then compared to the VP1 sequences of two previously used vaccine strains, O/PanAsia (JQ321837) and O/PanAsia-2 (JN676146). The antigenic relationship of these three viruses was calculated by the two dimensional-virus neutralization test. At the nucleotide level, 47 single variants were identified, of which 19.00% were in the 5' untranslated region (UTR), 79.00% in the polyprotein region, and 2.00% in the 3' UTR region. Approximately half of the single nucleotide polymorphisms that have occurred in 1D gene resulted in amino acid (AA) substitutions in the VP1 structure. The single nucleotide polymorphisms also caused AA substitutions in other structural proteins, including VP2 and VP3, and some non-structural proteins (Lpro, 2C, and 3A). The O/PanAsia-2/QOM-15 shared higher sequence similarity with O/PanAsia-2 (91.00%) compared to O/PanAsia (87.30%). Evaluating r-value showed that the antigenic relationship of O/PanAsia-2/QOM-15 with O/PanAsia-2 (29.00%) was greater than that of the O/PanAsia (24.00%); however, all three viruses were immunologically distinct. After 10 years, the alteration of virus antigenicity and the lack of detectable adaptive pressure on VP1 sequence suggest that studying genetic dynamics beyond the VP1 region is necessary to evaluate FMDV pathogenicity and vaccine failure.

Seroprevalence of antibodies to non-structural protein of foot-and-mouth disease virus in vaccinated dairy cattle.

Foot-and-mouth disease (FMD), a highly contagious viral disease of livestock, is endemic in Iran. To investigate the prevalence of antibodies against 3ABC non-structural protein (NSP) of FMD virus, a cross-sectional study was conducted on dairy cattle in eight cities of Kurdistan Province from May to September 2016. Serum samples (n = 283), were collected from cattle vaccinated with the recommended dose of a commercial vaccine and tested by a Competition enzyme-linked immunosorbent assay. Results showed the overall seroprevalence of antibodies against NSP of FMD virus in the vaccinated cattle was 22.30% (95.00% CI: 17.40 - 27.20%). The seroprevalence of antibodies was affected by geographical regions, with the highest seroprevalence related to the samples of vaccinated cattle in the cities of Marivan 95.00% (95.00% CI: 92.50 - 97.50%) and Saqqez 38.50% (95.00% CI: 32.80 - 44.20%). In terms of age, the highest seroprevalence of antibodies to FMD virus 26.70% (95.00% CI: 21.60-31.80%) belonged to ≤ 24-month-old cattle. These findings suggest that the presence of NSP antibodies in vaccinated cattle indicates the risk of infection with FMD virus serotypes circulating in the west of the province, so further studies with a larger sample size are recommended.

Two Dimensional Anion Exchange-Size Exclusion Chromatography Combined with Mathematical Modeling for Downstream Processing of Foot and Mouth Disease Vaccine.

The production of high-quality purified virus particles in high quantities for vaccine preparation requires a scalable purification procedure in the downstream step. A purification scheme based on combined strong anion-exchange and size exclusion chromatography (2D-AEC-SEC) was developed for the production of non-structural protein-free foot and mouth disease vaccine, and the whole procedure was accomplished with 77.9% virus yield. Additionally, a mathematical modeling and a simulation approach based on a plate model of chromatography were developed and matched with the experimental chromatography data to improve prediction of retention behavior and save time in the development of the downstream scale-up method. The purified pooled virus fraction obtained from the final polishing step had a purity higher than 85% based on analytical size exclusion analysis. Moreover, more than 90.1% of residual DNA (rDNA) was removed from the purified vaccine. The analysis of purified virus particles by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), dynamic light scattering (DLS), high performance size exclusion chromatography (HP-SEC), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and transmission electron microscopy (TEM) provided clear evidence of purity and demonstrated that the final product is structurally spherical, intact particles qualified for formulation as a vaccine product.

Foot and Mouth Disease virus-loaded fungal chitosan nanoparticles for intranasal administration: impact of formulation on physicochemical and immunological characteristics.

Nasal vaccination is a promising, needle-free alternative route for parenteral vaccination. This study introduces a simple, scalable nasal vaccine delivery formulation for Foot and Mouth Disease virus (FMDv) using chitosan (CS) nanoparticles and assesses the potential of fungal CS for use as nanocarriers for mucosal vaccines. Fungal CS was extracted from fungal biomass and physiochemically characterized. FMDv-loaded CS nanoparticles, prepared using an ionic gelation technique, were characterized for particle size, zeta potential, morphology, loading efficiency and virus particle release. The immunogenicities of nasally applied FMDv-loaded fungal or commercial shrimp CS were compared with intraperitoneally administered fluid vaccine in guinea pigs. The nanoparticles had varied sizes (221.9-281.2 nm), positive electrical charge (+7 to +13 mV) and excellent antigen-loading capacity (93-97%). In vitro release studies revealed a biphasic virus particle release for all CS nanoparticles. Higher serum titers were developed with CS formulations than with free virus and were comparable with the titers for intraperitoneally administered fluid vaccine. Significantly higher IgA levels were found after the administration of nasal vaccine than after fluid vaccine or free virus. Overall, CS-FMDv nanoparticles stimulated humoral and mucosal immunity following intranasal administration. Fungal CS polymers were potent mucosal immunoadjuvants and showed promise as alternative sources of CS for mucosal vaccine formulations.