FIG. 6.

Adoptive transfer of CCR5^+/+ leukocytes into CCR5^−/− mice restores permissiveness to VACV infection. Hematopoietic leukocytes from CCR5^+/+ mice were isolated and transplanted into irradiated CCR5^+/+ and CCR5^−/− mice as described in Materials and Methods. After 2 weeks, transplanted mice were either mock or EGFP-VACV infected (10⁴ PFU). (A) At the indicated times p.i., mice were euthanized and VACV titers in lungs, BAL fluid, and spleens of recipient CCR5⁺/⁺ (▪)and CCR5^−/− (░⃞) mice were determined. The data are representative of two independent experiments. The dotted line indicates the lower level of detection for VACV. ND, not detected. (B to M) Single-cell suspensions from the BAL fluid, spleens, and mLNs of recipient CCR5⁺/⁺ (▪) and CCR5^−/− (░⃞) mice were obtained and stained with PE-Cy5-conjugated anti-CD4/CD8/F480 and APC-conjugated anti-CD3/CD11c antibodies at the indicated time points. Values are the mean CD4⁺ (B, D, and F) and CD8⁺ (C, E, and G) T-cell, CD11c⁺ cell (H, I, and J), and F4/80⁺ cell (K, L, and M) counts ± standard errors from two independent experiments. ░⃞, total VACV-infected CCR5^+/+ CD4⁺/CD8⁺ cells; (□), total VACV-infected CCR5^−/− CD4⁺/CD8⁺/CD11c⁺/F4/80⁺cells. *, P < 0.05; **, P < 0.01.