<i>Ehrlichia</i> are observed in the filopodia of mouse macrophages.

<p>(A) <i>E. muris-</i>infected mouse macrophages probed with <i>Ehrlichia</i> Hsp60 antibody (left), DAPI (middle) (thick arrows indicate DNA of <i>E. muris,</i> and thin arrows indicate mouse macrophage nuclei), and merged figure (right). (B) IOE-infected mouse macrophage probed with <i>Ehrlichia</i> Hsp60 antibody (left) (thin arrow indicates filopodium), DAPI (middle), and merged figure (right). (C) Scanning electron micrograph of <i>E. muris-</i>induced filopodium in a mouse macrophage; thin arrow indicates the filopodium. (D) The interior of a mouse macrophage from which the cell membrane has been removed contained <i>E. muris</i>. (E) Higher magnification of <i>E. muris</i> in a mouse macrophage. (F) Scanning electron micrograph of an <i>E. muris</i> bacterium. (G, H) Scanning electron micrograph of IOE-induced filopodia in mouse macrophages; thin arrows indicate the filopodia. (I) IOE microorganisms in a mouse macrophage. (J) Scanning electron micrograph of a single IOE bacterium. (K) Uninfected mouse macrophage. (L) High magnification of an opened uninfected mouse macrophage. (M) Transmission electron micrograph of a mouse macrophage that contained an <i>E. muris</i> morula (thick arrow), N, nucleus. Scale bar, 1 micrometer.