Ex vivo inducing cultured Epstein-Barr virus specific cytotoxic T lymphocytes and evaluation of their killing effect

Abstract

This study was aimed to explore the method for induction and expansion of EB virus specific cytotoxic T lymphocytes (EBV-CTL) in vitro, and to detect their killing effect. Peripheral blood mononuclear cells (PBMNC) were collected from 6 EBV seropositive healthy donors, and EBV-transformed B lymphoblastoid cells (BLCL)were used as the antigen-presenting cells and antigen stimulant which was irradiated by 40 Gy (60)Co irradiator. The autologous PBMNC and irradiated BLCL were cultured to induce and expand the EBV-CTL, and the immunophenotype was identified by the flow cytometry. The killing effect of the EBV-CTL against the autologous BLCL (autoBLCL), the autologous PHA cultured B lymphoblastoid cells( PHA-BLCL), the allogeneic BLCL (alloBLCL) and the K562 cells were measured with LDH release assay under different effector-to-target ratio. The results showed that the 6 cell lines of EBV-CTL were induced and expanded from the EBV seropositive healthy donors, the overall increase in cell numbers varied from 18.6 to 55.0 times. After 10 stimulations, the specific killing efficiency of the EBV-CTL for the autoBLCL were 59.4%, 43.2% and 29.0% under the effector-to-target ratio of 20: 1, 10: 1 and 5: 1. The nonspecific killing efficiency for the PHA-blast, alloBLCL and K562 cells were 7.1%, 9.4% and 10.3% (P < 0.05) under the 20: 1 ratio; 6.6%, 8.3% and 8.1% (P < 0.05) under 10: 1; 5.4%, 7.3% and 6.3% (P < 0.05) under 5: 1, respectively. It is concluded that the EBV-CTL can be successfully induced and expanded ex vivo for specific killing of HLA matched BLCL and may become a potential treatment for EBV related post-transplant lymphoproliferative disorders.