Evaluation of Quil-A, E. coli DNA and Montanide™ ISA 206 adjuvant combination on the antibody response to foot-and-mouth disease vaccine in sheep.

Vaccination is one of the basic strategies in the fight against foot-and-mouth disease (FMD) in endemic regions. Today, commercially available FMD vaccines are prepared with inactive whole virion, which has low immunogenicity. Therefore, considerable effort has been devoted to finding novel adjuvants. Although mineral oils are among the most common adjuvants, it is still difficult to provide a long-term and robust immune response. Combined adjuvant systems are currently being studied to solve the problem. Saponins and CpG-ODNs have been shown to increase the immune response to vaccines individually in various studies. In this study, the effect of different adjuvants and their combinations (Quil-A, E. coli DNA, and MontanideTM ISA 206) on total and neutralizing antibody response in sheep was investigated. According to the results, the Quil-A group induced the highest antibody level, followed by the combination of Quil-A and the E. coli DNA group. The group containing E. coli DNA also caused a higher antibody response than the group containing only MontanideTM ISA 206 for certain days of sampling. These affordable alternatives of saponin and CpG sources can be used individually to increase the potency of the FMD vaccine for mass vaccinations of sheep. Keywords: foot-and-mouth disease; vaccine; adjuvant; Quil-A; E. coli DNA; combination of adjuvants.

Booster administration can make a difference in the antibody response to intradermal foot-and-mouth disease vaccination in cattle.

Foot-and-mouth disease (FMD) is a highly contagious and economically important viral disease of cloven-hoofed animals. Routine vaccination is one of the preferred methods of protection against this disease in endemic countries. For protective immunity against FMD, repeated immunizations with frequent administration are required. Intradermal immunization has many advantages over intramuscular administration of vaccines. In this study, a commercial tetravalent FMD vaccine adjuvanted with Montanide ISA 206 was administered to cattle via the intramuscular (2 mL [n = 10] and 0.5 mL [n = 9]) and intradermal (0.5 mL [n = 11]) routes. Booster doses were administered 28 days later using the same vaccine and routes. Serum samples were collected on days 0, 7, 14, and 28 post-vaccination (pv) and at 30 and 60 days post-booster. Homologous and heterologous virus neutralization tests and liquid-phase blocking and isotype ELISAs were used to measure the antibody response. The results showed that intradermal administration of quarter doses of the vaccine provides an equal or better virus neutralization antibody response than intramuscular administration of the same dose of vaccine after booster administration in cattle. This means that four times more cattle can be immunized with the same amount of vaccine using the intradermal route without compromising immunity.

Effect of simultaneous administration of foot-and-mouth disease (FMD) and anthrax vaccines on antibody response to FMD in sheep.

PURPOSE: Foot-and-mouth disease (FMD) and anthrax are important diseases in sheep. Vaccination is a favorable strategy against both infections. Simultaneous administration of vaccines does generally not impede the immune responses of each other, although there are some exceptions, and it may help reduce the labor and costs of vaccination as well as distress on animals. Although oil adjuvant FMD vaccine has been tried with live anthrax vaccine in cattle, there are no reports on the simultaneous use of both vaccines in sheep. MATERIALS AND METHODS: In this study, FMD seronegative sheep were used to investigate the impact of the simultaneous vaccination of FMD and anthrax on FMD antibody titers of sheep. Virus neutralization test and liquid phase blocking enzyme-linked immunosorbent assay were used to determine the antibody response to the FMD vaccine. RESULTS: The results demonstrated that both vaccines can be used simultaneously without any interference with the FMD response. Moreover, the simultaneous administration with anthrax vaccine had a stimulating effect on the early (day 7 post-vaccination) virus neutralization antibody response to the FMD vaccine. CONCLUSION: The simultaneous use of the FMD and anthrax vaccines did not hinder the response to the FMD vaccine in sheep.

Influence of vaccine potency and booster administration of foot-and-mouth disease vaccines on the antibody response in calves with maternal antibodies.

Foot-and-mouth disease is one of the most important viral diseases of cloven-hoofed animals. Mass vaccination is an effective method to control the disease and is frequently utilized in endemic regions. Sufficient protection of young animals is important in mass vaccination campaigns. Maternal antibodies negatively affect the success of vaccination. Hence, determination of the optimal vaccination age is crucial for the uninterrupted protection of young animals. This study was performed to identify the effect of vaccine potency and booster administration on serum neutralizing antibody titers of calves with different levels of maternal antibodies. Calves (n = 111) on a state farm were used in this study. Oil adjuvant foot-and-mouth disease vaccines with 3 PD50 and 6 PD50 potencies were used with or without booster administration. Serum samples were collected each month up to day 120 postvaccination. Virus neutralization tests were used to measure the serum neutralizing antibody titers and estimate the protection period by using pre-determined cut-off values for protection. The results revealed that a vaccination with a 6 PD50 potency vaccine, preferably followed by a booster dose, should be used to overcome maternal immunity for incessant protection.

QS-21 enhances the early antibody response to oil adjuvant foot-and-mouth disease vaccine in cattle.

PURPOSE: One of the most important tools against foot-and-mouth disease, a highly contagious and variable viral disease of cloven-hoofed animals, is vaccination. However, the effectiveness of foot-and-mouth disease vaccines on slowing the spread of the disease is questionable. In contrast, high potency vaccines providing early protection may solve issues with the spread of the disease, escaping mutants, and persistency. To increase the potency of the vaccine, additives such as saponin and aluminium hydroxide are used. However, the use of saponin with an oil adjuvant is not common and is sometimes linked to toxicity. QS-21, which is less toxic than Quil A, has been presented as an alternative for use with saponin. In this study, the addition of QS-21 to a commercially available foot-and-mouth disease water-in-oil-in-water emulsion vaccine was evaluated in cattle. MATERIALS AND METHODS: After vaccination, serum samples were collected periodically over 3 months. Sera of the QS-21 and normal oil vaccine groups were compared via serum virus neutralization antibody titre and liquid phase blocking enzyme-linked immunosorbent assay antibody titre. RESULTS: The results showed that there was a significant early antibody increase in the QS-21 group. CONCLUSION: Strong early virus neutralizing antibody response will be useful for emergency or ring vaccinations against foot-and-mouth disease in target animals.

Chitosan-based systems for intranasal immunization against foot-and-mouth disease.

Inactivated conventional vaccines against foot-and-mouth disease (FMD) are used routinely in endemic countries and are effective against clinical disease. Increased systemic IgG levels can be obtained with these vaccines whereas local response at the mucosal sites where the virus primarily enters the organism and replicates remains very limited. The aim of this study was to develop a safe, non-invasive and antigen compatible system for mucosal delivery of the FMD antigen which induces both the systemic and local immunity. Gel formulations were prepared using different types of chitosan at different concentrations and were incorporated with the whole inactivated FMD virion. The immune responses in guinea pigs were determined following intranasal administration. Chitosan-based FMD vaccine formulations have been shown to induce FMD antigen-specific serum IgG and nasal IgA levels, the latter response being significantly stronger as compared to that obtained following subcutaneous administration of the FMD antigen in Freund's incomplete adjuvant. Our results suggest that intranasal immunization with inactivated FMD virion delivered in the presence of chitosan is very promising, inducing both systemic and local immune responses.