Figure 6. Adoptively transferred Gr1⁺ (Ly6C⁺) monocytes home to the intestine and prevent extensive pathology in CCR2^−/− mice.

(A) Sorted cells were adoptively transferred to infected CCR2^−/− mice on day 3 post-infection and the ilea were examined at day 9 by H&E staining of paraffin sections. Typical lesions (asterisk) were observed in the ileum of infected CCR2^−/− mice that did not receive cells (Control) or received F4/80⁺ singly positive cells. CCR2^−/− mice that received Gr1⁺ (Ly6C⁺) F4/80⁺ cells show well-preserved architecture in the ileum, similar to wild type mice. Representative of two similar experiments containing 2 animals per group. Scale bar = 200 µm (15 µm inset). Right panels are enlarged views.

(B) Adoptively transferred Gr1⁺ (Ly6C⁺) monocytes home to the ileum of infected mice. Sorted, CFSE labeled Gr1+ (Ly6C⁺) F4/80⁺ monocytes i.v. inoculated into C57BL/6 mice on day 3 after oral infection. One day following adoptive transfer (day 4 after oral infection), ilea were collected and frozen sections were examined by fluorescent microscopy. Recruitment of CFSE labeled Gr1⁺ (Ly6C⁺) monocytes was observed in the lamina propria region in the villi and in the crypt region, which contained lymphocytic aggregations. Control represents C57BL/6 mouse that was infected but did not receive CFSE labeled cells. Scale bar = 20 µm.