Production of MEP1 and flagellin antigens

MEP1 was produced by having the gene synthesized and placed into a protein production vector (pET100/D-topo, GeneArt, Invitrogen). The resulting plasmid was transformed into E. coli BL21-DE3, and recombinant protein was induced via the lac operon. Recombinant MEP1 was then purified from bacterial urea extracts using nickel column chromatography and low pH elution. Purified MEP1 was dialyzed against 10 mM Tris buffer. Lachnospiraceae flagellin antigens including CBir1, 14-2 Fla1, A4 Fla3, and FlaX were produced as described previously (6, 8).