Fig. 4.

Infrequent sequence variation in MHC class II–restricted HCV epitopes in persistently infected chimpanzees. HCV RNA isolated from the serum of four persistently infected animals (CBO603, CBO609, CH-503, and NM1238) was amplified by way of PCR, and multiple molecular clones were sequenced to identify amino acid changes in 10 CD4 T cell epitopes compared with a consensus sequence of the infecting genotype 1a 1/910 strain. The frequency of each sequence is indicated to the right in each box. Viral sequences from animals expressing the restricting class II MHC allele are highlighted.