Fig. 6. LB cells transfected with CD44v4-v10 cDNA show more efficient local tumor formation and lymph node accumulation than LB cells transfected with standard CD44 cDNA or LB cells transfected with mutated CD44v4-v10 cDNA. Green fluorescent protein (GFP) cDNA was transfected into LB-TRv (TRv-G), LB-TRs (TRs-G) (both derived from independent CD44 transfections different from those of the corresponding nonfluoresceinated lymphoma cells) and parental LB (LB-G) cells. A quantity of 3x10⁶ cells from each transfected cell population was s.c. injected into BALB/c mice. The size of the local tumor (± s.e.m.) at the injection site (A) was measured at different time points after tumor inoculation (5 mice from each group were killed at each time point). Invasion of a peripheral lymph node (B) by the green lymphoma cells at different time points after tumor inoculation is indicated by the normalized mean (± s.e.m.) fluorescence intensity (MFI) of the whole organ (5 animals from each group were tested for lymph node invasion at each time point). In another experiment, BALB/c mice were s.c. inoculated with 3x10⁶ green LB cells transfected with mutated CD44v4-v10 cDNA (TRvM-G), green LB cells transfected with wild-type CD44v4-v10 cDNA (TRv-G) or green parental LB cells (LB-G). At each time point, 5 mice from each group were killed. Local tumor size (C) (± s.e.m.) and the intensity of lymph node invasion (D) (± s.e.m.) were assessed at different time points after tumor inoculation. *P<0.05; **P<0.01 by Mann-Whitney, compared with LB-G (A,B) or TRv-G (C,D). Note that the asterisks in C and D mark the two lines (LB-G, TRvM-G).