Complementarity-determining region 3 (CDR3) size analysis of TCR Vβ7, Vβ13, and Vβ22 transcripts in Cou-LS tumor cell line analyzed with fluorescent Cβ, Jβ2.3, and Jβ2.5. cDNA made from total RNA extracted from Cou-LS were amplified in a PCR reaction primed by Vβ7/Vβ13/Vβ22 and Cβ-specific primers. The unlabeled amplification products were elongated with nested fluorescent Cβ, Jβ2.3, and Jβ2.5. Aliquots were subjected to electrophoresis and analysis on an automated sequencer. Cou-LS tumor cell line showed three TCR β transcripts corresponding to Vβ7/Jβ2.3, Vβ13/Jβ2.5, and Vβ22/Jβ2.5.