Figure 1. Neutrophils are rapidly recruited to sites of sand fly bite where they phagocytose L. major parasites.

(A-B) Number of CD11b⁺F4/80⁺ macrophages/monocytes (A) and CD11b⁺Gr-1⁺7/4⁺F4/80⁻MHCII⁻Ly6G⁺ neutrophils (B) recruited into the ear (+/− SD; n≥4 ears/group/day) 1 or 6 days after being bitten by infected or uninfected sand flies. The number of cells in a naïve mouse ear is shown for day 1. (C) Ear sections from LYS-eGFP mice (green) bitten with uninfected (left) or L.m.-RFP (red) -infected (right) sand flies 2 hours prior to harvesting tissue. Arrows point to sites of proboscis penetration. See also movies S1 and S2. (D) 2P-IVM time-lapse images from the ears of LYS-eGFP mice (green) beginning 40” after exposure to uninfected (left) or L.m.-RFP (red) -infected (right) sand files. Circles represent sites of sand fly proboscis penetration. (E) Maximum intensity projection images across X, Y, and Z dimensions derived from 2P-IVM of the ear of a LYS-eGFP mouse (green) 2 hours after exposure to L.m.-RFP (red) -infected sand flies. Dermal and epidermal layers defined by the presence or absence of collagen (blue), respectively, are indicated. Arrows point to sites of proboscis penetration and neutrophil “plug” formation. See also movies S3 and S4. (F) Image obtained from a 2P-IVM time-lapse series of the ear of a LYS-eGFP mouse (green) 3 hours after exposure to L.m.-RFP (red) -infected sand flies. Arrows point to neutrophils with one or more intracellular parasites. See also movies S5 and S6. Scale bars, 30µm (C–E), 20µm (F).