[Analysis of CDR3 sequence of TCR Valpha6, Valpha10 and Vbeta23 oligoclonal T cells in one APL case]

To investigate the clonality and the pattern of CDR3 sequence of TCR Valpha and Vbeta repertoire in patients with acute promyelocytic leukemia (APL).

The CDR3 of TCR Valpha 29 and Vbeta 24 subfamily genes were amplified in mononuclear cells from peripheral blood of one case with APL using RT-PCR. The positive PCR products were further labeled with fluorescent and analyzed by genescan technique for the CDR3 size, to evaluate clonality of the detectable TCR Valpha and Vbeta T cells. The products of the oligoclonal T cells were analyzed by sequencing to define the sequence of CDR3.

Oligoclonal T cells expressed TCR Valpha6, Valpha10 or Vbeta23 genes were identified from the APL patient. The molecular characteristics of the CDR3 of Valpha and Vbeta genes rearrangement were Valpha6NJalpha17, Valpha10NJalpha35 and Vbeta23NDbeta1NJbeta2.7. The amino acid sequence of CDR3 region in TCR Valpha 6, Valpha10 and Vbeta23 subfamilies were CAMRENSAGNK, YLCAGDELLWECA or CASSSKWAGGTYEQY, respectively. These sequences were accepted by GenBank (Accession Number EU544946, EU544947 and EU647219).

Three idiotype Valpha and Vbeta sequences are identified in a case with APL, which is thought that may mediate the host specific immunity response for leukemia cells in APL. It might provide data for farther research on the specific immunotherapy of APL.