The Experimental Study On The T-Cell-Receptor Idiotypic DNA Vaccine To Induce Immunologic Reaction To Lymphocytic Malignancy

Objective:In most T eel] malignancies,there are T cell receptors (TCR) expressed on the surface of the tumor cells. The idiotyes of the TCR can serve as tumor associated antigens for anti - tumor immunotherapy. TCR idiotypic DNA vaccine may generate anti - idiotypic immunity against the tumor. This study was undertaken to investigate the anti-tumor immuneologic effects induced by TCR idiotypic DNA vaccine on BALB/C mice.Methods: The rearranged gene fragment coding TCR Y Vregion of the Jurkat cell line was obtained by RT - PCR technique The PCR product was cloned into the eukaryocyticexpressive vector pcDNAs to construct pcDNA3/TCR Y .Afterconfirmed by sequncing .pcDNAs/TCR Y plasmids were amplifiedin bacteria extracted by alkaline lysismethod . then to be used as DNA vaccine .Twenty-four BALB/C mice were divided equally into there groups : (1) group pcDNAs: the mice were injectedintramuscularly with pcDNAs 100ug; (2)group pcDNA3/TCR Y : Themice were injected intramuscularly with pcDNA3/TCR Y 100ug; (3) group pcDNA3/TCR Y - IL - 2: The mice were injectedintramuscularly with pcDNA3/TCR Y 100ug plus IL-2 5ug ascytokine adjuvant . Inoculations were given three times at two-weekintervals . The specific anti -idiotypic antibody was detected byindirect immunofluorescence staining. The mRNA in skeletal muscle cell was detected by RT-PCR.Results: We obtained the recombinant plasmid containingidiotypic TCRYV1 fragment of the jurkat cell line . The expressivegene fragment was 333bp long .Analyses of the TCR Y fragmentshpwed that it contained three epitopes .It was showed that specific anti-idiotypic antibody could be found since four weeks after the first immunization and came to the climate on the sixth week .The antibody titers of the same time were higher in grouppcDNA3/TCR Y -IL-2 than in group pcDNA3/TCR Y (po.01) .Thehighest antibody titer was 1:640 in the group pcDNA3/TCR Y-IL-2, whereas the highest was 1:160 in the group pcDNA3/TCRY .There were mRNA expression in skeletal muscle cell couldbe found in group pcDNAs/TCR Y and group pcDNA3/TCR Y -IL-2 on fifth day after inoculation.Conclusion: We successfully obtained the Lymphoma specificTCR Y VI recombinant plasmid of the Jurkat cell line .The expressive gene fragment of TCR Y VI was 333bp long .Analyses ofthe TCRyVl fragment showed that it contaied three antigenepitopes. This recombinant could be used as DNA vaccine toinduce effectively the specific anti-idiotypic antibody againstlymphoma. Using IL - 2 as immunologic adjuvant could significantly increase the antibody titers .