Predicted amino acid sequences of BV 5.1 CDR 3 domains of T cells from patients 1 and 2 following 14 days of culture with antigen (heparin:PF4). For each unique sequence identified (clonotype), a portion of the BV and BJ regions and the complete CDR3 loop region is shown. “Clonotype frequency” is the percentage of clones sequenced that encoded the amino acid sequences shown. A common CDR3 loop region motif (P G T G) shared by responding T cells of the 2 patients is highlighted in bold.