Analysis of Tcrb rearrangements. (Upper panel) A schematic representation of the murine Tcrb gene is shown with its Vβ, Dβ, Jβ, and Cβ segments. The relevant HindIII sites (H) are shown. The J_β2 and Cβ probes are shown as thick lines. (Lower panel) An example of Southern blot analysis is shown. Mouse splenic DNAs are analyzed on lanes 1 through 18. Quantification of the clonal rearrangements is made by comparison to a serial dilution of tumoral DNA into normal spleen DNA (100%, 25%, and 10%) included on each membrane. Black arrows indicate the clonalTcrb rearrangements. The open arrow shows incomplete DJ rearrangements that were not taken into account. Samples in lanes 9, 10, and 17 demonstrated major tumor loads. Samples in lanes 2 and 15 demonstrated minor tumoral loads.