TCL1^tg/tgTIR8^−/− cells are leukemogenic. (A) CD19⁺ splenocytes (10⁶ cells) were purified from 2 different TCL1^tg/tgTIR8^−/− mice and injected intraperitoneally into 8-week-old Rag2^−/− γc^−/− male mice (n = 9 each group). Mice were bled monthly, and analyzed for the appearance of CD19⁺CD5⁺ monoclonal population by flow cytometry; after 3 months mice were sacrificed, spleen removed and single cell suspension analyzed by flow cytometry for the expression for CD19 and CD5. One representative mouse shown. (B) Histopathologic examination of spleen of Rag2^−/− γc^−/− mice injected with TCL1^tg/tgTIR8^−/− (one representative animal sacrificed after 3 months of 9 analyzed): microscopic evaluation 40× and 100×.