Electron microscopy and immunogold labelling of CDT. Immunoelectron microscopic analyses of OMVs from wild type C. jejuni strain. 81-176 (A-C) and the cdtA::km mutant (D-F) using anti-CdtA (A, D), anti-CdtB (B, E), and anti-CdtC antisera (C, F). Arrows show the gold particles associated with OMVs. The square in the upper right corners show enlargements of parts of the micrographs. Bars correspond to 100 nm.