Immunogold electron microscopy (IEM) reveals pili like structure associated CagI in wild-type <i>H. pylori (Hp).</i>

<p><i>H. pylori</i> strains were grown on BHI agar plates and immunogold labeling of ultrathin sections was performed as described in Materials and Methods. (<b>A</b>, <b>B</b>, <b>C</b>, and <b>D</b>) Wild-type <i>H. pylori</i> stained with anti-CagI and gold-labeled secondary antibody. (<b>E</b>) Wild- type <i>H. pylori</i> stained with rabbit pre-immune (preimm.) serum and gold-labeled secondary antibody. (<b>F</b>) Isogeneic mutant <i>Hp∆cagI</i> stained with anti-CagI and gold-labeled secondary antibody. (<b>G</b>, <b>H</b>, and <b>I</b>) Isogenic Hp∆cagX, Hp∆cagV, and Hp∆cagE mutant strains showing absence of pili in TEM sections. Scale bars indicate 100 nm. Arrowheads indicate location of gold-labeled secondary antibody.