RESUMEN
Background Cell immunologic therapy for retinoblastoma(RB)is becoming a hot research topic.Cancer-testis antigen is a human immunogenic protein and is used to treat some tumors.However,its effect on RB has not been investigated.Objective The present study was to discuss the antigen specific anti-tumor effect of cytotoxic T lymphocytes(CTL)induced by the cancer-testis antigen,NY-ESO-1-sensitized dendritic cells(DCs),on human RB.Methods PCR was performed to amplify target gene fragments from the NY-ESO-1 plasmids,and then the target gene fragments were digested with the restriction enzymes SalI and EcoRI.Harvested fragments were inserted into the pDC316 plasmid to construct the recombinant plasmid pDC316/NY-ESO-1.The expression of NY-ESO-1 protein in human RB cells strain,HXO-RB44,was detected by immunofluorescence and Western blot.Monocytes were isolated from 60 ml of peripheral blood from a healthy donor using Ficoll density-gradient centrifugation with a cell density of 1 × 107/ml.DCs isolated from blood were stimulated with recombinant human granulocyte-macrophage colony stimulating factor(rhGM-CSF)and recombinant human interleukin-4(rhIL-4).The recombinant plasmid pDC316/NY-ESO-1 was transfected into DCs and the DCs were co-cultured with T lymphocytes.The resultant CTL were used as effector cells.The growth of the CTL was detected by MTT assay.The CTL were then added into the growth medium used for culturing HXO-RB44 cells and the vitality of the HXO-RB44 cells was assayed by MTT assay.Results The sequence of the cloned DNA fragment of the recombinant plasmid pDC316/NY-ESO-1 was conforms with the sequence of the NY-ESO-1 gene.The expression of the NY-ESO-1 protein in HXO-RB44 cells was tested by immunofluorescence and Western blot.DCs were successfully induced with rhIL-4 and rhGM-CSF from PBMC.The recombinant expression plasmid pDC316/NY-ESO-1 was successfully transferred into DCs.These DCs had high expression of surface molecules such as HLA-DR(42.1％),CD80(54.2％),CD83(39.7％)and CD86 (94.8％).The CTL that was induced by DCs-sensitized with NY-ESO-1 specifically killed HXO-RB44 cells.CTL induced by the sensitized DCs had a stronger cytotoxic effect against HXO-RB44 cells compared with un-sensitized DCs and CTL un-induced with DCs,as shown by MTT asssay(P＜0.05).The anti-tumor activity was highest when the ratio of effector to target was 75∶1(P＜0.05).Conclusions DCs transfected by the recombinant plasmid pDC316/NY-ESO-1 can induce the proliferation of allogenic CTLs,which showed a specific anti-tumor effect against HXO-RB44 cells.These results present a new type of immunotherapy for the treatment of RB.