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Vaccination of the susceptible livestock with potent, safe and cost effective vaccine is the primary requirement to control foot-and-mouth disease (FMD) in an endemic country. In this study, an alternative approach was used in which structural protein genes of all the four serotypes of FMDV (O, Asia 1, A22 and C) were expressed separately in methylotrophic yeast Pichia pastoris. The recombinant polyproteins (P1) were characterized by SDS-PAGE and in Western Blot analysis. Partially purified protein was used for immunization in guinea pigs with different adjuvant formulations and immune response studied. Ninety micrograms of the recombinant protein per monovalent dose was used for immunization. A single injection of a monovalent or polyvalent vaccine was given to guinea pigs with various adjuvant combinations viz., Monovalent recombinant protein either adjuvanted with Montanide-ISA50V or Indigenous oil, Monovalent recombinant protein mixed with 1/10th dose of inactivated oil-adjuvanted virus vaccine and Polyvalent recombinant protein with Montanide ISA50V. FMDV specific humoral immune response was observed at about 28th day post vaccination. The immune response as assessed by indirect ELISA and Serum neutralization test titres was found to be 320-640 and 16-32, respectively. When challenged with virulent homologous type 'O' virus, the guinea pigs showed protective C index of 2.01,1.81, 2.56 and 2.48, respectively, with above said adjuvant combinations. The study has shown that yeast-expressed FMDV P1 polyprotein in a single dose could elicit a protective immune response in guinea pigs, and this could be a possible future vaccine candidate in homologous host.

Foot-and-mouth disease (FMD) is an economically important disease of cloven-hoofed animals. The multiplicity of FMDV serotypes in animals poses a central problem in the policy of vaccination and is of much concern to health authorities. Hence it is the practice of vaccination with polyvalent vaccine for prophylactic measure. In the present report, we analysed the early antibody responses elicited by FMDV quadrivalent (FMDV O, A, C and Asia 1 serotypes) double emulsion (Montanide ISA 206) vaccines in cattle. We observed variations between various viral serotypes in eliciting early antibody response although neutralizing antibody response against all the four serotypes were detected as early as fourth day following vaccination. The duration of immunity also appeared to maintain for long period. The neutralizing antibody titres were maintained well above 2log(10) even after 6 months of vaccination irrespective of serotypes. Thus, allows the possibilities of two vaccinations per year for the maintenance of herd immunity.

Seven pregnant ewes at the 10th to 12th week of pregnancy were vaccinated with foot-and-mouth disease (FMD) vaccine type Asia-1. All pregnant animals responded well with antibody production without any adverse effects. The maximum antibody titer was noted 3 to 4 weeks after the vaccination. In the colostrum a high level of maternal antibodies persisted from 12 hrs to 6 weeks after birth. Irrespective of the presence of the maternal antibodies, the vaccinated lambs responded with antibody production within the first week of vaccination. The antibodies persisted up to the 12th week of vaccination. In another experiment five sheep were vaccinated with FMD type O vaccine and challenged with 10,000 TCID50 of virulent type O cell culture-adapted virus. The antibody titers in the vaccinated animals prior to challenge ranged between 1.26 to 1.65, while the four control sheep remained free from detectable antibody against virus type O. Pyrexia and viraemia developed present in all the control sheep but were absent in the vaccinated ones. Characteristic primary lesions on the dorsum of the tongue were observed after 48 hrs of virus challenge in the control sheep but were absent in the vaccinated ones.

Foot-and-mouth disease (FMD) vaccines prepared against types Asia-1 and O PEG-concentrated and adjuvanted with aluminium hydroxide gel were compared with oil-adjuvanted types Asia-1 and O vaccines in sheep. The study was conducted by inoculating 0.5 ml of monovalent vaccine under laboratory conditions and 1 ml dose of bivalent vaccine in field conditions. The antibody responses were monitored by serum neutralization and ELISA tests. The results indicate that PEG-concentrated gel vaccine was of comparable immunogenicity to oil-adjuvanted vaccine over a study period of 8 weeks. No significant difference was observed in the antibody response with monovalent or bivalent vaccine. However, to substantiate the present findings and reach a final conclusion, further studies with both vaccines may have to be carried out over a longer period of time.

Foot and mouth disease virus (FMDV) type 'O' was inactivated either with formaldehyde or binaryethyleneimine (BEI). Vaccines were prepared with inactivated virus incorporating aluminum hydroxide gel or mineral oil as an adjuvant. The antibody response in sheep was monitored by serum neutralization and ELISA test for a period of six months. Significant difference in antibody response was not observed between vaccines inactivated with formaldehyde or BEI. On the other hand significant difference in the antibody response was noticed between alhydrogel and oil vaccines. The high titer of antibodies stimulated by oil adjuvant vaccines persisted longer than those of alhydrogel vaccines within the period of study.

Foot and mouth disease virus type Asia-1 was inactivated either with formaldehyde or binaryethylenimine (BEI). Inactivated vaccines were prepared incorporating aluminium hydroxide gel or mineral oil as an adjuvant. The antibody response to the adult sheep was studied by ELISA and SN test for a period of 6 months. There was no difference in the antibody response between vaccines inactivated with formaldehyde or BEI. Whereas significant difference in the antibody response was observed between gel and oil vaccines. The high titres of antibody stimulated by oil vaccines persisted longer than those of gel vaccines within the period of study.