Histopathologic analysis of B-cell lymphomas in RzCD19Cre mouse tissues. (A) Histologic analysis of tissues from a normal mouse (i, iii, v; CD19Cre mouse, ID No. 47-4, male) and a B-cell lymphoma from a RzCD19Cre mouse (ii, iv, vi; ID No. 69-5, male). Paraformaldehyde-fixed and paraffin-embedded tumor tissues were stained with hematoxylin and eosin (iii-vi) or immunostained using anti-CD45R (vii; bottom right, inset) and anti-CD3 (viii; bottom right, inset). Also shown is a macroscopic view of the lymphoma from a mesenchymal lymph node (ii, indicated by forceps), which is not visible in the normal mouse (i). Mitotic cells are indicated with arrowheads (vi). Scale bars: 100 μm (iii-iv, vii-viii) and 20 μm (v-vi, insets in vii-viii). (B) Expression of HCV RNA in B-cell lymphomas from RzCD19Cre mice was examined by RT-PCR. The first round of PCR amplification yielded a 123-base pair fragment of HCV cDNA (upper panel), and a second round of PCR amplification yielded a 65-base pair fragment (lower panel). The β-actin mRNA was a control. As an additional control, the first and second rounds of amplification were performed using samples that had not been subjected to reverse transcription. NTC, no-template control. (C) Ig gene rearrangements in the tumors of RzCD19Cre mice. Genomic DNA isolated from B-cell lymphoma tissues of RzCD19Cre mice (ID Nos. 24-1, 24-4, 54-1, 56-5, 69-5, 31-4, 42-4, 43-4) and spleen tissues of a WT mouse (ID No. 21-2) was PCR amplified using primers specific for Vκ-Jκ genes. Amplification of controls was performed using genomic DNA isolated from a GANP transgenic mouse (GANP Tg#3) and in the absence of template DNA (no-template control, NTC). M, DNA ladder marker.