Abstract：The widely-used allergic diagnosis method depends on the binding of IgE, present in human patient sera. However, little correlation was demonstrated between serum immunoglobulin E(IgE) antibody level and the severity of clinical symptoms. Therefore, this study aimed to develop an in vitro cellular test system for evaluating potential allergenicity of foods via analysing the binding of mouse(Mus musculus) serum IgE to rat(Rattus norvegicus) basophilic leukaemia(RBL) cells and the degranulation of RBL-2H3 and RBL-1 cells. Female Balb/c mice (each 3-week-old) were orally sensitized 5 times with glycinin (Gly), ovalbumin (OVA), or potato acid phosphatase (PAP). The sensitized serum pool that obtained after sensitization was utilized to analyze the binding of mouse IgE to RBL cells and mediator release assay. Additionally, elicitation of allergic reaction was assessed by measurement of vascular permeability to investigate the correlation between the degranulation of RBL cells and severity of allergic reaction. Results indicated that the capacity of RBL-2H3 cells to bind mouse IgE was significantly higher than that of RBL-1 cells (P＜0.05). Good degranulation was induced in RBL-2H3 cell-line, while RBL-1 cell-line did the reverse. RBL-2H3 cell mediator release assay proved to be sensitive. Sensitized cells could be induced a maximal degranulation at a concentration of 10~100 ng/mL of allergens. This assay was also quite specific. Cells sensitized with sera from mouse with anti-OVA IgE did not degranulate following exposure to Gly. Furthermore, this assay had the ability to differentiate potential allergenicity of Gly, OVA and PAP. These functional data were found to be in line with the results of systemic anaphylaxis and demonstrated the ability of a protein to induce IgE-mediated allergic reactions. In conclusion, the RBL-2H3 cells, but not RBL-1 cells, is suitable for evaluating biological activity of different food allergens and form the basis of a useful model system for evaluating potential allergenicity of novel proteins.
