Immunospecificity of Immunoglobulin Y (IgY) Isolated from Eggs of Immunized Chicken against Salmonella enterica serovar typhi

Abstract

The discovery of IgY in chicken eggs has gained interest due to its use in immunodiagnosis, immunotherapy and treatment of diseases. This study used eggs from White Leghorn chicken immunized with a peptide antigen from Salmonella entrica serovar typhi, using precipitin ring formation in radial immunodiffusion assay as the indicator. IgY crude isolates from egg yolk was obtained by water dilution method. Bradford assay results showed that the total protein content of these crude isolates ranged from 1.5-7 mg /ml yolk during the egg laying period. SDS-PAGE detected the presence of IgY and measured its purity to be about 85%-94%. Radial immnudiffusion assay was used to determine the immunoreactivity of IgY against S. typhi. Peak diameters were observed at 100% heat killed bacteria (-1.26 x 105 CFU/ml) and 12.5% antibody dilution. Pearson analysis also showed that there is a strong positive correlation between the protein content and immunospecificity of IgY against heat killed S. typhi. Immunospecific reaction was also observed at 100%-12.5% S. typhi peptide antigen and 12.5% antibody dilution. Based on these results, IgYs in the crude isolates were immunospecific for the antigen in Salmonella typhi.