Figure 1

Tumors that grow progressively in the Rag2 ^-/- mice show a B cell phenotype. A. Increased forward and side scatter was used to gate out the large tumor cells, and they were then stained with a variety of makers to determine their cell surface phenotype. B. Southern blotting indicates that the UV-induced B cells tumors have a rearranged immunoglobulin heavy gene. DNA was isolated from two variants of UVBL-1 (Tr-1 and Tr-12). Both variants expressed a re-arranged IgM heavy gene compared to genomic DNA isolated from non-lymphoid tissue (mouse tail skin).