Kinetics of CD8-Sn⁺ cluster formation in livers of tumor-bearing DBA/2 mice under ADI. Frozen tissue sections were stained for CD8 T lymphocytes and Sn⁺ Kupffer cells with corresponding MoAbs. Six lobules per liver were analyzed under the microscope. (A) Immunohistochemical picture of sections, double-stained for CD8 (brown) and Sn (blue) in livers of tumor-bearing mice 12 days after ADI treatment. Show is the periportal area in which CD8 T lymphocytes and Sn⁺ Kupffer cells are mainly located and form cell clusters (original magnification × 400). pv, portal vein. (B) Double-staining of CD8 T lymphocytes and Sn⁺macrophages in mouse livers after ADI therapy. (□) Total number of CD8 T cells; (◊) the number of CD8 cells associated with F4/80⁺ cells in clusters; (○) the number of CD8 cells associated with Sn⁺ cells in clusters; (▵) the number of CD8 cell-Sn⁺ cell clusters. Data show the means and standard deviations from two experiments with 2 to 3 animals per time point. Data points without SD represent mean values for which the SD was smaller than 1.