Human-derived immune cells harbour <i>Leishmania</i> parasites in humanized mice.

<p>42 days after high dose infection (3×10⁶<i>L. major</i>), liver spleen and the site of infection were analyzed for the host parasite interaction. Cryosections of liver (A), and spleen (B) biopsies were stained for human CD45 (green), and <i>Leishmania</i> antigen (L-Ag, red). <i>L. major</i>-infected humanized mice appear in orange (CD45⁺ and L-Ag⁺ colocalization; white arrows). (C) Cryosections of footpad samples (site of infection) were stained for human CD68 (red), and L. antigen (L-Ag, green). The insert C-I highlights infected human CD68⁺ macrophages. The insert C-II highlights infected CD68⁻ cells. The blue-fluorescent DAPI nucleic acid stain was added to all staining (blue; nuclei). Bars represent 50 µm.