Effects of orally applied Fes p1-displaying L. plantarum WCFS1 on Fes p1 induced allergy in mice.

Group I grass pollen allergens are major contributors to grass pollen-related seasonal allergic rhinitis, and as such a primary target for allergen specific immunotherapy. In this study the potential therapeutic role of oral application of Lactobacillus plantarum WCFS1, directing cell wall attachment of the recombinant Fes p1 allergen, from Festuca pratensis was tested in a mouse model of Fes p1 allergy. For surface expression of Fes p1 allergen in L. plantarum WCFS1 pSIP system with inducible expression was used. Balb/c mice were sensitized with Fes p1 protein in alum and subsequently received live recombinant L. plantarum orally. Antibody levels (IgE, total IgG, IgG1, IgG2a, and IgA) were determined by ELISA. Differential eosinophil count in peripheral blood was performed. Reduced peripheral blood eosinophilia and increased serum IgG2A levels was detected in both groups which received live L. plantarum orally. Specific serum IgA levels were increased only in mice treated with the recombinant bacteria. Oral application of L. plantarum WCFS1 has a beneficial therapeutic effect in a mouse model of Fes p1 allergy. Cell surface expression of Fes p1 allergen potentiates this phenomenon in an allergen specific way.