Abstract: This study was devised to elucidate the role of intestinal mucosal immunity in the sensitization of mice by tropomyosin (TM) and in the alleviation of allergy symptoms by probiotics. Female and male BALB/c mice were sensitized and challenged by intraperitoneal (IP) injection of TM and were treated by oral administration of Bifidobacterium longum subsp. 1.2202 or Bacillus coagulans 09.712 for 20 consecutive days starting from Day 14. Anaphylaxis and diarrhea were evaluated, serum immunoglobulin(Ig)E and histamine (HIS) levels were determined. Intestinal mucosal mast cells and goblet cells were detected by histological analysis. Eosinophils and CD4＋ T cells were identified by immunohistochemistry. The results showed that female mice were more suitable for building TM-induced mouse model and probiotics could alleviate the allergy symptoms by downregulating intestinal mucosal immune response as manifested by decreased levels of HIS and TM-specific IgE. These results provide a theoretical basis for the mechanistic study of TM-induced food allergy and for understanding the therapeutic effect of probiotics on food allergy.

Key words: tropomyosin, seafood allergy, mucosal immune response, probiotic, Bifidobacterium longum subsp. 1.2202, Bacillus coagulans 09.712