Figure 3.

Proportions of polyfunctional CD4⁺ and CD8⁺ T cells to Epstein–Barr virus (EBV) proteins. Proportions of T cells with single, double, triple, quadruple and quintuple functions in response to EBV lytic (BZLF1) and latent (EBNA1, EBNA3A, 3B, 3C, LMP2) overlapping peptide pools were shown for 20 healthy long-term carriers (a) and for two patients with post-transplant lymphoproliferative disorder (PTLD) (b). The numbers in the pie charts represent the mean percentages (rounded up to integer) of T-cell subpopulations with respect to total responding CD4⁺ or CD8⁺ T cells. 5+ denotes T cells that have five functions; 4+ denotes T cells that have four functions and so on. In long-term carriers, EBNA3 proteins clearly stimulated larger proportions of polyfunctional CD8⁺ T cells among total responsive CD8⁺ T cells than other latent EBV proteins. BZLF1 protein stimulated similar proportions of polyfunctional CD8⁺ T cells to EBNA3 proteins. EBNA1 protein appeared to stimulate a higher proportion of polyfunctional CD4⁺ T cells among all the latent EBV proteins. In patients with PTLD, most T cells possessed only one function with none exhibiting five functions and rare cells showing three and four functions. No immunodominance hierarchies of EBV proteins were observed.