Outgrowth of TAg⁺B-cell lymphomas in the absence of TAg-competent T cells. (A) B cells (open symbols) or splenocytes (closed symbols) of CD19-CreER^T2 × LoxP-Tag and CD19-Cre × LoxP-Tag mice were transferred IV into Rag^−/− mice. Each recipient obtained 1 × 10⁷ B cells. To deplete residual T cells, α-Thy1.2 antibodies or isotype control was injected twice (day 0 and day 5). Tamoxifen was applied on days 1 to 5 after transfer. Blood samples were stained for TAg expression (left), and mice with palpable lymphoma burden were euthanized and presented as Kaplan-Meier survival graph (right). Mice showing TAg-unrelated signs of distress were censored. The log-rank test and Bonferroni post hoc test were performed. Adjusted P values are indicated. (B) B cells (1 × 10⁷) of CD19-Cre × LoxP-Tag mice were transferred IV into Rag^−/− recipients. Splenocytes of TAg-competent CD19-CreER^T2 × LoxP-Tag or TAg-tolerant CD19-Cre × LoxP-Tag mice were depleted for B cells and injected into the contralateral tail vein (5 × 10⁶ CD8⁺ T cells and 6-10 × 10⁶ CD4⁺ T cells). Blood samples were stained for TAg⁺ B cells to monitor lymphoma formation. Two-tailed Mann-Whitney U test was applied. Kaplan-Meier survival graph of tamoxifen-treated CD19-CreER^T2 × LoxP-Tag × OT-I and CD19-CreER^T2 × LoxP-Tag mice (10/20 cohoused control littermates, 10/20 separate breeding) (C) and Vil-Cre × CD19-CreER^T2 × LoxP-Tag mice and cohoused CD19-CreER^T2 × LoxP-Tag control littermates (D). Tamoxifen was given at 6 to 10 weeks of age. Censored mice were euthanized because of formation of other tumor entities or other signs of distress. The log-rank test was performed.