II . Detection of Antibodies to C 100 - 3 and 5 - 1 - 1 in Blood Donors and Patients with HCV of Genotype II

Hepatitis C virus (HCV) samples in 155 sera, from patients with chronic non-A, non-B liver disease and blood donors, were grouped into four genotypes (I, II, III, and IV) by amplification of core-gene sequences by polymerase chain reaction with typespecific primers. HCV genotypes were compared with various HCV-associated antibodies detectable by the first-generation ELISA (ELISA-1) with C100-3 protein and a second-generation immunoblot assay with four recombinant HCV proteins. Antibodies to C100-3 protein and those to its subsequence (51-1) were detected in 13 (93%) and 12 (86%), respectively, of 14 sera with genotype I HCV; 56 (79%) and 58 (82%) of 71 sera with genotype II; 13 (34%) and 6 (16%) of 38 sera with genotype III; and 11 (34%) and 4 (13%) of 32 sera with genotype IV. Amino acid sequences of C100-3 of genotype I HCV are conserved by 90% in genotype II, but only by 75% in genotypes III and IV. The sensitivity of ELISA-1, therefore, would be influenced by heterogeneity in C100-3 sequences of different genotypes. (J. Clin. Invest. 1993. 92:1529-1533.)