Protective immune response of the capsid precursor polypeptide (P1) of foot and mouth disease virus type 'O' produced in Pichia pastoris

Foot and mouth disease virus (FMDV) is the aetiological agent of a highly contagious vesicular disease of cloven-hooved animals. The gene coding for the capsid polyprotein (P1) of FMDV from serotype 'O' vaccine strain (O75Madras) was cloned and expressed in yeast Pichia pastoris. The expressed P1 protein was characterised by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and Western Blot analysis. Immunisation of Guinea pigs with recombinant P1 induced FMDV type O specific immune response. The humoral response to vaccine was measured by indirect ELISA and a serum neutralisation test (SNT). The Guinea pig sera showed high titres both in ELISA and SNT. Upon challenge with virulent Guinea pig adapted homologous type 'O' virus, the animals showed a protective index of 2.52. This study shows that the yeast expressed FMDV P1 could be a safe vaccine in non-endemic countries and a cost-effective vaccine in endemic countries. This is the first report on the production of FMDV structural proteins in yeast and their application as a vaccine.