Variations of immunoglobulins in colostrum and immune milk as affected by antigen releasing devices

Abstract

This work was conducted to examine the variation of immunoglobulins (Igs) in serum, immune milk, normal milk and colostrum upon implantation of a new Antigen Releasing Device (ARD). The core of each ARD housed an immunostimulating complex (ISCOM) that was made of adjuvant Quil A and type XIII lipase from a Pseudomonas sp. Each ARD was coated with polylactic acid, known as polylactide, that controls antigen release. Twenty lactating Chinese Holstein cows were divided into 2 groups (n = 10): test group and control group. All cows in the test group were implanted with a single injection in the right iliac lymph node with 3 types of ARDs, which were designed to release the antigens at d 0, 14 and 28 post-implantation. Blood and milk samples were collected from both groups, and colostrum samples were also collected from other post-partum cows in the same farm. Concentrations Of IgG1, IgA and IgM in whey and serum were measured by sandwich ELISA. The results showed that the IgG1, IgA and IgM concentrations in serum and whey from the test group were higher than from the control group. Among the three Igs measured, the Ig G1 concentration in serum was significantly higher at d 40 after ARD implantation, and the IgG, concentration in whey peaked at d 9, 17 and 30, which corresponded with release of the antigen. Based on Pearson's correlation between Ig concentration and production parameters, IgA concentration in normal milk was positively correlated with lactation period, which reflected IgA changes during the lactation period in immune milk. In colostrum, IgG1, IgA and IgM decreased abruptly from d 0 to 3, and then decreased slightly. In conclusion, serum IgG1 concentration can be affected by controlled release of the ARD, while whey IgA levels are primarily affected by lactation period. These results may be useful in future studies designed to regulate concentrations of Igs in immune milk.