Figure 5. Mammary gland and Tumor tissues from C3H/HeN•MMTV+ tumor-bearing mice show high levels of BST-2 and viral nucleic acids.

C3H/HeN•MMTV+ mice infected via milk during nursing were sacrificed after 2 pregnancies (n = 5, age = 5 months) or allowed to develop mammary tumor (n = 5, age = 5 to 7 months). As stated above, mice bearing tumor were sacrificed in accordance to the policies of the University of Iowa Institutional Animal Care and Use Committee. Mice were bled for PBMC isolation prior to euthanasia. PBMCs, lymph nodes, spleens, tumor tissues, and mammary gland tissues devoid of lymph nodes were used for DNA and RNA extraction. RNA was reverse transcribed to cDNA and used to quantify BST-2 mRNA levels (A and B). Single cells from the lymphoid and tumor tissues were subjected to FACS examination of BST-2 surface protein (C), while DNA was used to quantify proviral DNA (D and F); cDNA was quantified by RT-qPCR to determine levels of viral RNA expression (E and G). Cell-free plasma collected from the above infected and tumor-bearing mice (n = 5) were used for examination of plasma viral load by vRNA (H) or RT activity (I). All PCR data are normalized to GAPDH and presented as fold change relative to samples from the naïve and infected mice. RT activity was extrapolated from the RT standard curve and presented as fold change of RT units in 1 µl of infected plasma. Error bars are standard deviation; ** is significance with p value less than 0.01 and * is significance with p value less than 0.05. The numbers next to histogram legend denote mean florescence intensity (MFI) of surface BST-2 levels. Experiments were repeated several times with similar results.