CD4 and infection: T-cell epitopes defined in natural infection: Next, we determined whether CD4 and CD8 restricted epitopes described in natural infection were detected in conserved viral segments; 89 of 215 CD8 (41.4%) and 170 of 320 CD4 (53%) of HCV genotype-1 epitopes described in natural infection mapped to conserved viral segments within the HCV genotype 1 dataset (Fig. 3).