Effect of ritonavir on ATL cell growth and infiltration. (A) Mice were injected with ATL cells (2 × 107 cells) subcutaneously in the postauricular region. One day after inoculation, the mice were administered either RPMI 1640 or ritonavir (30 mg/kg/d) intraperitoneally every day for 30 days followed by observation for another month without therapy. Photographs of whole organs of RPMI 1640-treated ATL mice (left) and ritonavir-treated ATL mice (right) with enlarged spleen, liver, and lungs. (B-D) HE staining (B) and immunohistochemical staining using anti-CD4 (C) or anti-CD25 (D) in various organs of NOG mice 2 months after inoculation of ATL cells. Upper panels show various organs of mice treated with RPMI 1640, and lower panels represent various organs of mice treated with ritonavir. Magnification ×40.
