Immunomodulatory properties of protein hydrolysates

Consuming infant formula containing cow’s milk can lead to the development of cow’s milk allergy in neonates. To prevent this, intact cow’s milk proteins are cut into smaller peptides by hydrolysis. The resulting product, a hydrolysate, is less recognized as foreign by the immune system, and therefore prevents allergic reactions. Furthermore, previous studies showed that specific hydrolysates are also able to actively modulate the immune system, which could contribute to a decrease in allergic reactions. However, in order to apply hydrolysates in this way, more research on the underlying mechanisms of these effects were needed.
In this thesis we first investigated the immune effects of a range of hydrolysates in vitro. We found that soy, cow’s milk and wheat hydrolysates were able to modulate immune cell functioning, but that these effects were hydrolysate specific. Specific cow’s milk and soy hydrolysates were found to modulate the antigen-presenting cells via specific receptors, which could also affect the rest of the allergic response. Next, we showed that the administration of a cow’s milk hydrolysate in a mouse model for cow’s milk allergy indeed increased white blood cells with a modulating function, and did not induce allergic reactions. Also, a soy hydrolysate was found to decrease the permeability of the epithelium covering the intestinal wall, which could lead to less uptake of antigens into the body. Since we were also able to identify the hydrolysate fractions which were responsible for the observed effects, these studies contribute to the knowledge about immune modulating effects of hydrolysates and the design of better working hydrolysates for specific target groups.