IMMUNOLOGICAL EVENTS DURING THE INCUBATION PERIOD OF HEPATITIS-C VIRUS-INFECTION - THE ROLE OF ANTIBODIES TO E2 GLYCOPROTEIN

BACKGROUND: The study of the sensitivity of screening assays is greatl y facilitated by testing the sequential changes in seroconverting indi viduals. The aim of this study was to investigate the early immunologi c response after hepatitis C virus (HCV) infection and to evaluate whe ther HCV envelope (E2) recombinant antigen would provide a significant increase in sensitivity for detection of anti-HCV. STUDY DESIGN AND M ETHODS: Twenty hemodialysis patients who were seroconverting to anti-H CV were included in this study. They were followed up for a mean perio d (+/- SD) of 10.5 +/- 3.3 months, in which 13 to 46 serum samples per case were collected. Each sample was tested for anti-HCV by second-an d third-generation enzyme immunoassay (EIA-2 and EIA-3) and recombinan t immunoblot assay (RIBA-3). E2 antibodies were tested by a prototype EIA in which E2 was expressed as a recombinant antigen in Chinese hams ter ovary cells. RESULTS: Alanine aminotransferase elevation was obser ved in 13 of 20 cases. Reactivity against c100, c33c, c22, NS5, and E2 was detected in 15 (75%), 19 (95%), 15(75%), 2 (10%), and 17 (85%) pa tients, respectively; c33c was the most immunogenic antigen, followed in descending order by E2, c22, c100, and NS5. E2 antibody reactivity resolved the two RIBA-3-indeterminate cases. However, there was no cas e in which E2 reactivity preceded all other HCV antigens. Anti-Ee was found to react in all patients of genotypes la, Ib, and 3a but in only 2 of 4 patients of genotype 4a. CONCLUSION: In this group df seroconv erting individuals, E2 antigen was shown to be highly immunoreactive a nd did resolve some RIBA-3-indeterminate samples as being positive, on the basis of reactivity to multiple antigens, but it did not improve early detection of seroconversion.