DTG mice show evidence of CLL-like disease and hypogammaglobulinemia at 36 weeks. (A) Blood smears were developed with Wright-Giemsa stain. Images (×200 and ×600) were acquired using Nikon Eclipse E400 microscope (Nikon, Melville, NY) and Optronics camera running MagnaFire software (Optronics, Goleta, CA). Paraffin-embedded spleen and kidney sections were developed with hematoxylin and eosin. Images (×100 for spleen and ×200 for liver) were acquired using a Nikon i80 microscope and DigiFire camera running ImageSys digital imaging software (Soft Imaging Systems GmBH, Munster, Germany). DTG mice at this age show peripheral blood lymphocytosis with frequent occurrence of smudge cells (arrow, see inset), loss of splenic architecture, and infiltration of leukemic cells in liver (arrows). Scale bars: blood and liver, 100μM; spleen, 200μM. (B) Serum IgM and IgG levels were measured by enzyme-linked immunosorbent assay for groups of 12- and 36-week-old WT, dnRAG1, Eμ-TCL1, and DTG mice. Individual values and means (indicated by horizontal bar) are shown for each group; statistically significant differences between groups are indicated.