Flagellin as a good carrier and potent adjuvant for Th1 response: study of mice immune response to the p27 (Rv2108) Mycobacterium tuberculosis antigen.

We have recently expressed and characterized the product of the gene Rv2108 of Mycobacterium tuberculosis (MT), the p27 protein. Here, we investigated the immune responses against the p27 protein in the context of different pathogen associated molecular patterns (PAMPs). Different immunization protocols were used. BALB/c mice were immunized either with the p27 recombinant protein in Freund's adjuvant or in phosphate saline buffer (PBS), with a pcDNA3 plasmid containing the gene encoding the p27 protein, or with the Escherichia coli bacteria expressing the p27 protein genetically fused into the flagellin. We found that p27 expressed into the flagellin led to the strongest cellular responses, where we obtained the highest production of IFN-gamma and cell proliferation, an indication of specific Th1-like orientation of the immune response. We confirmed the role of flagellin in this response by using different immunization combinations.