DefinePK

Abstract

Background:   Foot and mouth disease (FMD) is ubiquitous  worldwide but endemic in many countries of Africa, Asia, South America, and the Middle East. Many reasons contribute to the incidence of viral diseases even in vaccinated animals. These reasons include low antigenic payload, low PD50, improper formulation, unstable vaccine containing antigen, and genetically different from field strain. Among these, the most important one is the low antigenic load per dose of the vaccine. Vaccine failure is mainly due to the direct use of  virus suspension in the vaccine without the concentration of viral antigen. Another reason to concentrate the antigen is small volume storage in the vaccine bank. These issues are mostly concerned with developing countries like Pakistan which lack antigen concentration technology. The concentration of the virus is a major milestone to be achieved for the production of an effective vaccine as well as for the diagnostic tool. Methods:  Different techniques including precipitation with polyethylene glycol, ammonium sulfate, methanol, and filtration through an ultra-filter membrane were used for the concentration of viral suspension. Antigen quantification in terms of µg/ml was determined through size exclusion chromatography by using Sephacryl S-300 as a stationary phase. Results:  Percentage recovery of FMDV calculated through analysis of chromatograms found 77.80%, 59.75%, 32.50%, and 13.83% for polyethylene glycol, ammonium sulfate, ultra-filtration, and methanol treated samples respectively. Conclusion : Classical polyethylene glycol precipitation showed a maximum percentage recovery of foot and mouth disease virus as compared to other concentration methods. Keywords: Foot and mouth disease virus (FMDV); Concentration Methods; Polyethylene Glycol (PEG); Size Exclusion Chromatography (SEC); Sephacryl S-300