Polyacrylamide gel electrophoresis of IgH CDRIII PCR products obtained from single CLL cells and H-RS cells: (A) case 1, (B) case 2. All PCR products are identical in size in each case. M, 100 basepair (bp) molecular size ladder with 100- and 200-bp markers shown. H-RS(1) indicates that the PCR products were obtained from CD30⁺ H-RS cells. In a separate experiment, CD20⁻ H-RS cells were isolated for study and the PCR products are shown under H-RS(2).