Eμ-myc/bcl-2^−/− reconstituted mice develop characteristic Eμ-myc lymphoma. (A) Representative immunophenotyping FACS plots of lymphomas arising in Eμ-myc and Eμ-myc/bcl-2^−/− mice. Single-cell suspensions were prepared from fresh tumor samples and stained with monoclonal antibodies to Ly5.2, Ly5.1, B220, CD19, IgM, IgD, CD4, CD8, Gr-1, Mac-1, and Ter119 antibodies. All lymphomas were confirmed as donor-derived by expression of Ly5.2 antigen. (B) The overall proportion of pro/pre-B and immature B lymphomas arising in moribund Eμ-myc and Eμ-myc/bcl-2^−/− reconstituted mice.