Detection and antigenic properties of three fragments of the VtaA10 passenger domain. The stalk, collagen repeats and head of the entire VtaA10 passenger domain were produced in E. coli Rosetta. Size separated proteins were detected by the Sypro tangerine stain. In a parallel SDS-PAGE, recombinant proteins were immunodetected using a monoclonal antibody against the histidine C-terminal tails (αHis) of the recombinant polypeptides or serum of animal 172 collected at 42 dpt. E. coli Rosetta transformed with an empty pASK-IBA33 plasmid was used as a negative control (C−). Molecular size standards are shown on the left of the figure. Arrows indicate weak specific bands for the head and multimeric stalk domains of VtaA10. * Indicates multimeric and ♦ monomeric forms of the stalk.