Оптимизация условий выделения IgY из желтка куриных яиц

Abstract

Background . Immunoglobulins Y (IgY), obtained as a result of immunization of poultry against a specific pathogen, are highly active against this pathogen. Currently, passive immunization using IgY is very promising due to the lack of reactivity of IgY with respect to mammalian Fc receptors, low cost and ease of isolation. Egg yolk is a rich source of IgY, the total content of which exceeds 100 mg per chicken egg. Due to the significant differences between blood serum and egg yolk, the isolation of immunoglobulins from the latter requires specific purification from the lipid part of the yolk. This is achievable through a two-fold treatment, including the procedure for separating the water-soluble fraction (WF) from the lipid matrix at pH 4-5 and isolating IgY from the WF. Purpose . The purpose of this work is to optimize the conditions for the isolation of IgY, which would allow the implementation of a variant of deep processing of egg yolk. Materials and methods . To achieve this goal, chicken eggs were taken as an object of study, and statistical (RCCP), analytical (biuret), physicochemical (SDS-PAGE, ultrafiltration) methods were used. Results . The following conditions for IgY isolation were selected: freezing of the yolk solution in a mixture of sodium phosphate buffer: water acidified to pH 5.0 in a ratio of 1:6 at a temperature of -20°C and decanting from lipid components by filtration during spontaneous thawing at room temperature. The resulting water-soluble fraction was then subjected to precipitation with sodium chloride at a concentration of 10 wt. % and subsequent concentration on the UAM-10 membrane, which made it possible to achieve the content of the main substance (IgY) of at least 95% on a dry matter basis. Conclusions . The conditions for the selective isolation of IgY from egg yolk by optimizing the process were established: the dilution ratio of the yolk suspension is 6 and the concentration of the added NaCl salt to the water-soluble fraction is 10 wt. %; as a result, a regression equation Y=8.1834X_1+5.5258X_2+0.6005X_1^2+0.2819X_2^2 was obtained, which provides the maximum degree of purification of the target product from ballast proteins and impurities, which makes it possible to obtain an IgY-containing fraction with a protein content , varying in the range of 11.5 - 12.1 g / l and a purity of at least 95%.