Protein transport across the small intestine in food allergy

Abstract

In view of the imminent deficiency of protein sources for human consumption in the near future, new protein sources need to be identified. However, safety issues such as the risk of allergenicity are often a bottleneck, due to the absence of predictive, validated and accepted methods for risk assessment. The current strategy to assess the allergenic potential of proteins focuses mainly on homology, stability and cross-reactivity, although other factors such as intestinal transport might be of added value too. In this review, we present an overview of the knowledge of protein transport across the intestinal wall and the methods currently being used to measure this. A literature study reveals that protein transport in sensitised persons occurs para-cellularly with the involvement of mast cells, and trans-cellularly via enterocytes, while in non-sensitised persons micro-fold cells and enterocytes are considered most important. However, there is a lack of comparable systematic studies on transport of allergenic proteins. Knowledge of the multiple protein transport pathways and which model system can be useful to study these processes may be of added value in the risk assessment of food allergenicity.

Neonatal mono-colonization of germ-free mice withLactobacillus caseienhances casein immunogenicity after oral sensitization to cow's milk

“…We previously observed that sensitization of GF mice to CAS tended to be less efficient than sensitization to whey proteins [19]. Roth-Walter et al also showed that soluble BLG and ALA, but not insoluble CAS, are readily transcytosed through enterocytes while uptake of CAS micelles occurs mainly through Peyer's patches [36,37]. We then hypothesized that sensitization of GF mice to insoluble CAS was less efficient than that to soluble BLG, because of an impaired uptake of CAS in Peyer's patches that are hypoplastic in GF mice compared to CV mice [33].…”

Dose-time-response relationship in peanut allergy using a human model of passive cutaneous anaphylaxis

“…Furthermore, the events taking place in the gastrointestinal tract of individuals with allergy before systemic distribution of the allergen are bypassed in this model. 7 We are truly grateful to all study participants (donors and recipients) who took part in the study. To the Editor:…”

Maternal Allergy and the Presence of Nonhuman Proteinaceous Molecules in Human Milk

“…From the intestinal tract to the blood, proteins can be absorbed by both paracellular and transcellular pathways. In reviewing the literature, Reitsma et al suggested that a difference in intestinal absorption of proteins between non-sensitized and sensitized persons can take place by both pathways [10]. Which of these two is involved in the transfer of dietary proteins into human milk is not known.…”

“…A prerequisite for the uptake of proteinaceous molecules through the paracellular pathway is an impaired intestinal barrier. Reitsma et al pointed out that sensitized persons have an increased level of mast cells that release IgE-induced tryptase [10]. The tryptase affects the tight junctions in the intestinal barrier, leading to an increased permeability, which could allow the passage of proteinaceous molecules.…”

“…The presence of these nonhuman proteinaceous molecules in human milk raises the question of how they end up there. It has been suggested that dietary proteins can be transferred through the intestinal barrier by both paracellular and transcellular pathways [10]. Furthermore, nonhuman proteins present in the mother's blood might also be transferred by these pathways through the mammary epithelia into the milk [11,12].…”