Serial transplantation and engraftment of lymphomas cells from HTLV-1-HU-NOD/SCID mice. (A) Pooled cells from the spleen and MLNs of HTLV-1-HU-NOD/SCID mouse (#7749) were serially transplanted intraperitoneally into naive NOD/SCID mice. Cells from lymphomas in the mesenteric lymph nodes (B), in the secondary recipient mice (#7749-2) as visualized by H&E (C), and immunohistochemistry staining for human CD45 (Hu-CD45; D). Phenotypic analysis of lymphoma cells in the MLN of secondary recipients demonstrate CD4⁺ staining (E), coexpression of HTLV-1 gag antigen p19^gag (F), and expression of CD25 (G). H&E staining demonstrating diffuse large-scale lymphomas in the spleen (H), kidney (I), and small intestine (J) of secondary recipient NOD/SCID mice. (K) Immunohistochemical analysis for human CD45 in the spleen of secondary recipient mice that developed lymphoma.