Immunomodulatory Protein Hydrolysates and Their Application

Abstract

Immunomodulatory protein hydrolysate consumption may delay or prevent western immune-related diseases. In order to purposively develop protein hydrolysates with an optimal and reproducible immunomodulatory effect, knowledge is needed on which components in protein hydrolysates are responsible for the immune effects. Important advances have been made on this aspect. Also, knowledge on mechanisms underlying the immune modulating effects is indispensable. In this review, we discuss the most promising application possibilities for immunomodulatory protein hydrolysates. In order to do so, an overview is provided on reported in vivo immune effects of protein hydrolysates in both local intestinal and systemic organs, and the current insights in the underlying mechanisms of these effects. Furthermore, we discuss current knowledge and physicochemical approaches to identify the immune active protein sequence(s). We conclude that multiple hydrolysate compositions show specific immune effects. This knowledge can improve the efficacy of existing hydrolysate-containing products such as sports nutrition, clinical nutrition, and infant formula. We also provide arguments for why immunomodulatory protein hydrolysates could be applied to manage the immune response in the increasing number of individuals with a higher risk of immune dysfunction due to, for example, increasing age or stress.

Keywords: Toll-like receptor; bioactive peptide; functional foods; immunomodulation; protein hydrolysate.

Figure 1

The process of protein hydrolysis and its products. (A) chemical reaction of protein hydrolysis; (B) different hydrolysates serve different purposes.

Figure 2

Overview of immune effects induced by protein hydrolysates on the (A) intestinal epithelial cells; (B) intestinal immune cells; (C) mesenteric lymph nodes; (D) systemic immune system.

Figure 3

Overview of mechanisms described in the literature via which peptides can exert immunomodulatory effects in the cell. Peptides can (A) directly stimulate receptors; (B) be taken up in the cell via a peptide transporter and interfere with inflammatory signaling pathways; or (C) be taken up into the cell via endocytosis and inhibit inflammatory signaling pathways.

Figure 4

Summary of the application possibilities of protein hydrolysates. These hydrolysates are currently being used in sport nutrition, clinical nutrition, and infant formula, mainly because of their good digestibility and hypoallergenicity. Recent research indicates that specific protein hydrolysates could optimize the current products in multiple ways. Also, there is evidence that new protein hydrolysate products could be beneficial for specific target groups.

Figure 5

Overview of T helper cell subsets and their interactions and their relation to specific diseases.