CTL responses to latent EBV proteins. (A) Polyclonal lines were generated from a patient with HD by stimulating PBMC with autologous LCL. After 3 in vitro stimulations, responding cells were enriched for CD8⁺ cells, and the repertoire of CTL responses to the latent EBV proteins was determined by lysis of autologous fibroblasts infected with vac recombinants encoding individual latent EBV genes. Specific lysis was determined by a standard CRA. Effector cells were added at an E:T of 10:1. (B) Responding cells from the polyclonal lines described above were cloned by limiting dilution in the presence of autologous LCL stimulators. Specificity of the clones was determined in a CRA by measuring specific lysis of autologous fibroblasts infected with vac recombinants. Clone MF 2D7 lysed vac/LMP2-infected target cells at an E:T of 5:1.