Materials and Methods

Establishment and Maintenance of Cell Lines. CTL clones LC13 and SC17 were isolated from EBV-sero § donors LC (HLA-A1,-, B8, B18, DR3, DRll) and SC (HLA-A1, A31, BS, B51, DR3, DR4) after in vitro stimulation of fresh PBMC with the autologous lymphoblastoid cell lines (EBV-LCL) 1 transformed with EBV derived from the IARC-BL74 cell line (18). Both CD8+ clones are HLA-B8 restricted and recognize the EBV CTL epitope FLR-GgAYGL (19).

PHA blasts were generated by stimulating PBMC with PHA (Commonwealth Serum Laboratory, Melbourne, Australia) and after 3 d, growth medium (10% FCS/R. PMI 1640) containing MLA-144 supematant and riD2 (20, 21) was added. PHA blasts were propagated with biweekly replacement of rlL-2 and MLA-144 supernatant (PHA free) for up to 8 wk. EBV-LCL were established by exogenous A-type EBV transformation of peripheral B cells and maintained in growth medium (22). All cell lines were regularly screened for mycoplasma contamination. Blood donors used in this study were healthy laboratory staff and were tested for previous EBV exposure using standard methods to detect IgG antibody to the EBV capsid antigen (viral capsid antigen)(23).