Immune-enhancing effects of β-lactoglobulin glycated with lactose following in vitro digestion on cyclophosphamide-induced immunosuppressed mice

Su-Hyun Chun,Kwang-Won Lee

doi:10.3168/jds.2021-20681

Abstract

β-Lactoglobulin (β-LG) is a major milk protein, making up more than 53% of the total whey proteins, and is seen as a valuable ingredient in food processing because of its high essential amino acid content and diverse functional applications. The Maillard reaction can occur during the storage and processing of food and generate various beneficial effects, including anti-allergenicity, antioxidant, and immunomodulatory effects. The addition of an β-LG-lactose conjugate (LGL) produced by the Maillard reaction was shown to have a strong immune-enhancing effect, increasing both nitric oxide generation and cytokine expression through activation of RAW 264.7 cells, even after in vitro digestion. Furthermore, daily LGL administrationresulted in the upregulation of several immune markers in a cyclophosphamide-induced immunosuppressive mouse model, indicating that this treatment stimulates multiple immune cells, including macrophages, natural killer cells, and lymphocytes, enhancing the proliferation and activation of both the innate and adaptive immune responses. Taken together, these findings indicate that consuming LGL on a regular basis can improve immunity by increasing the natural production of various immune cells.

Highlights

Milk proteins are known for their high nutritional value in the food industry as a key source of protein (Villa et al, 2018), whereas milk-derived allergens, such as casein, can limit their use in food products (Li et al, 2021; Villa et al, 2021)
Previous research has shown that Maillard reaction products (MRP) derived from whey proteins have immune-enhancing properties, raising nitric oxide (NO) and pro-inflammatory cytokine production through stimulation of RAW 264.7 macrophages (Chun et al, 2016) and that MR-conjugate (LGL), derived from β-LG and lactose, is a major immune-enhancing active constituent derived from whey protein (Chun et al, 2020)
We investigated the production of NO and the mRNA expression of pro-inflammatory cytokines (TNF-α, IL-1β, and IL-6) in RAW 264.7 macrophage cells treated with digested LG-lactose conjugate (LGL) in the absence of LPS (Figure 4)

Summary

Introduction

Milk proteins are known for their high nutritional value in the food industry as a key source of protein (Villa et al, 2018), whereas milk-derived allergens, such as casein, can limit their use in food products (Li et al, 2021; Villa et al, 2021). There is a growing concern in improving immune system preservation for ever-increasing human life span (Lee and Lawrence, 2018; Yang et al, 2019). This indicates that numerous researchers have continued to investigate substances for improving immunity (Yun et al, 2018; Monmai et al, 2019; Yang et al, 2019; Yoo et al, 2019)

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