Transplantation of Tax-Tg mouse-derived splenic mononuclear cells to NOD/SCID mice. (A) Experimental design of the transplantation assay. (B) Remarkable splenomegaly was observed in the lymphoma-reconstituted NOD/SCID mouse. Spl indicates spleen; and Liv, liver. The dotted line shows the outline of the enlarged spleen. (C) Cytospin analysis of spleen cells isolated from reconstituted lymphoma in the NOD/SCID mouse. The spleen was filled with ATL-like lymphomatous cells. (D) Surface marker analysis of lymphomatous cells from spleen. These had the identical phenotype of lymphomatous cell reconstituted by Tax-Tg–derived splenic mononuclear cells: CD2⁻, CD4⁻, CD8⁻, cytoplasmic CD3⁺, and surface CD25⁺ and CD44⁺. (E) Schematic representation of the PCR assay to identify and confirm the Tax transgenic integration site. Lck-Tax transgenes were tandemly inserted on the chromosome 4 (Chr.4) in the original transgenic animals. (F) Genotyping of mononuclear cells in the spleen and BM. WT PCR product (300 bp) was detected in both the normal and CSC-transplanted NOD/SCID spleen and BM. However, Tax-Tg (TG) PCR products identifying the expected integration site of the transgene (200 bp) were detected only in the reconstituted ATL-like lymphomatous cells in spleen and BM. TP+ indicates transplantation.