Cell-based immunological assay: complementary applications in evaluating the allergenicity of foods with FAO/WHO guidelines

Abstract

There are drawbacks for the decision tree strategies recommended by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) (FAO/WHO, 2001) in allergenicity assessment. In this study, we evaluated the allergenic activity of glycinin (Gly), ovalbumin (OVA) and potato acid phosphatase (PAP) by using an RBL cell-based immunological assay and the decision tree strategies. We then further analyzed the complementary applications between the RBL cell-based immunological assay and the decision tree strategies. A bioinformatical analysis predicted that the ranking of potential allergenicity was Gly>OVA>PAP, which was determined by analyzing the linear-epitope regions. However, the RBL cell-based immunological assay can determine the ability of the linear and conformational epitopes to induce allergic reactions. A pepsin digestion assay indicated that Gly was more stable compared with OVA and that PAP had no stability in simulated gastric fluid. However, this approach cannot fully reflect the results of food proteins digested in the gastrointestinal tract. Anaphylactic reactions in Balb/c mice and optimal β-hexosaminidase release of RBL-2H3 cells were induced with Gly followed by OVA; no significant response and <10% release were obtained with PAP. Compared with the animal models, the RBL cell-based immunological assay is more suitable for evaluating the allergenic activity of food proteins based on the simple characteristics of the testing system. The RBL cell-based immunological assay may play a “referee” role when inconsistent results between a bioinformatical analysis and a pepsin digestion assay occur, and animal models may be used to further dissect the mechanisms of the allergic responses. Thus complementary applications between the RBL cell-based immunological assay and the decision tree strategies will be a good choice to conduct a complete evaluation of the allergenic potential of foods.