Immunoglobulin gene rearrangements are monoclonal. (A) Ig RNAs were isolated from purified B cells of a Tg splenic B-cell lymphoma, amplified by RT-PCR, and resolved. –RT control is shown (left). Primers to the 3′ constant region (3′Cμ and 3′Cκ) Ig sequences and degenerate primers to the variable regions (5′VH and VK) were used in pairs as indicated. RNA of purified, polyclonal B cells from normal, non-Tg littermate control (right) is compared with Tg lymphoma (left). (B) Lymphoma RNA from first or sixth transplanted passage of malignancy was amplified with primers specific for Bcl6 (▪) or Blimp-1 genes (□) by real-time PCR and compared with splenic B2 control. Relative expression levels were determined by the 2–ΔΔCt method where ΔΔCt = ΔCt, sample – ΔCt, reference with Bcl6 or Blimp-1 serving as samples and β2-microglobulin as a reference.
