The use of caprylic acid for the extraction of the immunoglobulin fraction from egg yolk of chickens immunised with ovine α-lactalbumin

The extraction and purification of serum-derived immunoglobulin fraction in the egg yolk of hens by the combined treatment of the raw egg yolk with caprylic (octanoic) acid and ammonium sulphate is described. This simple two-step method proved to be both rapid, reproducible and suitable for batch processing of pooled egg yolk. The method recovered in excess of 130 mg of immunoglobulin per egg yolk. Two chickens were inoculated at two weekly intervals with 100 μg each of ovine α-lactalbumin over a ten week period. The α-lactalbumin antigen was purified by a hydrophobic-interaction chromatographic procedure and further purified by a gel excision-elution process. No precipitating antibodies could be demonstrated in gel diffusion techniques with this antibody. The specificity and specific activity of the antibody were monitored by western blotting and demonstrated the presence of highly specific antibodies to ovine α-lactalbumin in the treated egg yolk. The extraction procedure had no adverse effects on antibody titre. We concluded, and confirmed previous reports, that the use of chickens for the production of highly specific antibodies to mammalian proteins with particular reference to milk proteins presented numerous advantages over conventional procedures.