CD4⁺ T cells, CD8⁺ T cells, γ-δ T cells, and NK cells in healthy EBV-seropositive patients respond to autologous LCL after culture for 20 hours. Percentage of PBMCs producing IFNγ and stained for CD4, CD8, γ-δ TCR, and CD56 (NK) markers were measured in 10 healthy EBV-seropositive (A) and healthy EBV-seronegative patients. (B) PBMCs were incubated with autologous LCL at a ratio of 10:1 (PBMC/LCL) followed by cell surface marker staining and intracellular staining for IFNγ. CD4⁺ T cells and CD8⁺ T cells compose a major fraction of IFNγ-producing cells (C) or of percent IFNγ-producing cells (D) in response to autologous LCL in healthy EBV-seropositive patients.