Immunomodulatory Properties of Recombinant Lactic Acid Bacteria Encoding a Major House-dust Mite Allergen

RATIONALE: Experimental human and animal studies demonstrated that lactic acid bacteria (LAB) strains have beneficial effects on allergy.This study evaluated some immunomodulatory properties of the Lactobacillus plantarum strain producing a recombinant form of Der p 1 allergen.METHODS: The coding cassette for the MBP-ProDer p 1 fusion protein was inserted into an expression vector suitable for the allergen production in the LAB used. Human monocyte-derived dendritic cells (MD-DCs) from healthy donors were stimulated with the wild type or recombinant bacteria. Cell surface markers expression (CD80, CD86, CD40, HLA-DR) and cytokine production (IL-12, IL-10) were analysed by FACS and ELISA respectively. Stimulated DCs were further co-cultured with naïve or memory autologous T cells and lymphoproliferation and cytokine production (IFN-γ, IL-4, IL-5) determined.RESULTS: A recombinant LAB producing intracellularly large amounts of MBP-ProDer p 1 was obtained. This strain induced as wild type a dose-dependent cytokine production by DC (IL-12 and IL-10), upregulated the expression of costimulatory molecules (CD80, CD86 and CD40) and the maturation marker HLA-DR. Interestingly, in both cases stimulated DCs induce the lymphoproliferation of T naïve or T memory cells and favour the production of IFN-γ instead of Th2 cytokines (IL-4 and IL-5).CONCLUSIONS: As recombinant L. plantarum has similar strong immunomodulatory properties as wild type strain its potential regulatory effect to limit house dust mite allergy appears promising. RATIONALE: Experimental human and animal studies demonstrated that lactic acid bacteria (LAB) strains have beneficial effects on allergy.This study evaluated some immunomodulatory properties of the Lactobacillus plantarum strain producing a recombinant form of Der p 1 allergen. METHODS: The coding cassette for the MBP-ProDer p 1 fusion protein was inserted into an expression vector suitable for the allergen production in the LAB used. Human monocyte-derived dendritic cells (MD-DCs) from healthy donors were stimulated with the wild type or recombinant bacteria. Cell surface markers expression (CD80, CD86, CD40, HLA-DR) and cytokine production (IL-12, IL-10) were analysed by FACS and ELISA respectively. Stimulated DCs were further co-cultured with naïve or memory autologous T cells and lymphoproliferation and cytokine production (IFN-γ, IL-4, IL-5) determined. RESULTS: A recombinant LAB producing intracellularly large amounts of MBP-ProDer p 1 was obtained. This strain induced as wild type a dose-dependent cytokine production by DC (IL-12 and IL-10), upregulated the expression of costimulatory molecules (CD80, CD86 and CD40) and the maturation marker HLA-DR. Interestingly, in both cases stimulated DCs induce the lymphoproliferation of T naïve or T memory cells and favour the production of IFN-γ instead of Th2 cytokines (IL-4 and IL-5). CONCLUSIONS: As recombinant L. plantarum has similar strong immunomodulatory properties as wild type strain its potential regulatory effect to limit house dust mite allergy appears promising.