Influence of beta-lactoglobulin on the uptake and passage of IgG in the intestinal cell in vivo and in vitro.

摘要

Studies were conducted to determine the effects of the whey protein Beta-lactoglobulin (BLG) on the delivery and transport of a particular immunoglobulin, IgG. The presence of the two proteins in vivo in certain animals prompted an investigation into the possibility that BLG might have some effect on the passage of IgG not only to the intestinal cell but also through it.; The first experiment consisted of a serum analysis of blood from neonatal piglets. Two trials were conducted in this experiment, the first with a duration of 5 days (trial 1) and the second 28 days (trial 2). The influence of BLG on IgG uptake, endogenous production of various immunoglobulins and sera levels of BLG were investigated.; The second part of the initial investigation examined intestinal growth, morphology and function. Enzymatic activity, total DNA synthesis, crypt depth and villus height were all parameters used to evaluate the effect of BLG on intestinal development of the neonatal piglet. Piglets from the sow reared control group had the greatest villi height after 28 days as well as total DNA. Piglets fed colostrum supplemented with BLG had the greatest total DNA after 5 days with no differences observed in enzymatic activity among all treatments.; As a result of the in vivo results, the second experiment was performed to determine whether BLG served as a facilitator of transcellular transport of IgG in a human intestinal cell line (Caco-2). Fluorescently labeled IgG was added with unlabeled IgG to determine specificity of binding to the apical receptor. Unlabeled IgG and labeled IgG competitively bound to the polymeric Ig receptor. Uptake of IgG was evident after incubation with the Caco-2 cells but passage through the monolayer was highest in cells in which BLG was also added.