Evaluation of the efficacy of human antibodies against hepatitis C virus antigens
HCV. responseclearance,
Background: Hepatitis C virus (HCV) is a major health problem worldwide particularly in Egypt. The humoral immune response has an important function in the control of HCV infection. Aim: To study the role of neutralizing antibodies in Hepatitis C Virus (HCV) clearance in infected individuals. Methods: This study was carried out on apparently healthy blood donors (n=200). Detectable HCV antibodies were assessed by commercial ELISA. Specific human immunoglobulin targeting peptides derived from HCV E1 /E2 regions in blood samples were measured by in house optimized ELISA. Human IgG purification was carried out from both samples positive and negative for HCV RNA in order to evaluate its neutralizing activity invitro using Huh 7 cells. Results: The studied cohort included 96/200 subjects who were positive for HCV antibodies, among which: 56/96 (58%) samples were positive for HCV RNA (group 1) and 40/96 (42%) samples had undetectable HCV RNA (group 2). ELISA results showed that Human HCV Immunoglobulin (HHI) targeting HCV E1 synthetic peptide (a.a 315-323) was detectable in 63/96 (66%) and HHI targeting HCV E2 (a.a 412-419) were positive in 14/96 (15%) while 19/96 (19%) were positive for HCV E2 (a.a 517-531). (HHI) higher than the cutoff level against peptide HCV E1 (a.a 315-323) were detected in 22/63 (35%) in blood donors group 2 and positive in 41/63 (65%) in group 1. HHI against peptide HCV E2 (a.a 412-419) were positive in 7 (50%) in blood donors group 2 and also positive in 7 (50%) of group 1. In addition HHI targeting HCV E2 (a.a 517-531) were positivein 11 (60%) in group 2 compared with 8 cases (40%) in group 1. Purified human antibodies from cases positive for HCV antibodies and negative forHCV RNA showed invitro neutralization at concentrations 30 and 10 μg/ml while the same concentration of purified human IgG from cases positive for HCV RNA showed no viral neutralization. Conclusions: The tested epitope (s) derived from HCV envelope E1 and E2, are important for viral clearance and hence can be used for HCV vaccine development.