In vivo imaging of BCL₁ lymphoma.

(A) BCL₁ lymphoma cells were transduced with the pGC-gfp/luc fusion construct, sorted for GFP, and injected intravenously into syngeneic BALB/c mice. GFP⁺cells were passaged 4 times through BALB/c animals and finally through SCID mice to avoid lymphocyte contamination at time of cryoconservation. The final BCL₁-gfp/luccells are CD19⁺ and show a homogeneous GFP expression. (B) 7 × 10³ BCL₁-gfp/luccells were injected intravenously into syngeneic BALB/c mice. Three hours after injection (day 0) a bioluminescent signal (ventral and lateral views) was detectable from the lungs (first 2 images), and after 4 to 5 days tumor engraftment in liver and spleen could be visualized (second 2 images). Tumor growth leading to massive hepato-splenomegaly could be followed over the next 5 weeks (third set of images), and an infiltration of lungs and lymph nodes was observed in final disease stages (5 weeks; final image). The scale to the left of the images describes the color map for the photon count. (C) Quantification of tumor growth by measuring light emission from BALB/c mice after intravenous injection of 2 × 10³BCL₁-gfp/luc cells (●, n = 5) compared with a disease-free control animal (■).