Measurements of HCV neutralizing antibodies and of HCV-specific CD4+ and CD8+ cells using hepatitis C virus pseudo-particles (HCVpp)

Abstract Background For the medical management, it would be of great relevance to get a diagnostic marker predicting the outcome of infection. Objectives For this purpose, the envelope antigens of the individual HCV strain in a patient was tested for their capacity to induce neutralizing antibodies and cytotoxic T lymphocytes. Study design A system for the measurement of neutralizing antibodies as well as for the stimulation of a HCV-specific T-cell response using pseudo-typed HCV particles (HCVpp) was established. A report on results of a pilot study conducted with blood specimens of 19 chronically infected patients is also presented. Results Neutralization of HCVpp could be measured in nearly all HCV sero-positive patient samples. Nevertheless, in more than half of the patient samples (11/19), no HCV-specific CD4+ response was detectable. In addition, HCV-specific CD8+ response was measurable in most of the patients when HCVpp were used for T-cell stimulation. Although the same antigens (HCVpp) were used, there was no relevant correlation between neutralization titers and T-cell response. Conclusion Our study shows that HCVpp are appropriate antigens for specific stimulation of lymphocytes as well as for the investigation of antibody neutralization activity.