title: Methodologies for the Analysis of HCV-Specific CD4(+) T Cells.
abstract: Virus-specific CD4(+) T cells play a major role in viral infections, such as hepatitis C virus (HCV). Viral clearance is associated with vigorous and multi-specific CD4(+) T-cell responses, while chronic infection has been shown to be associated with weak or absent T-cell responses. Most of these studies have used functional assays to analyze virus-specific CD4(+) T-cell responses; however, these and other detection methods have various limitations. Therefore, the important question of whether virus-specific CD4(+) T cells are completely absent or primarily impaired in specific effector functions during chronic infection, has yet to be analyzed in detail. A novel assay, in which virus-specific CD4(+) T-cell frequencies can be determined by de novo CD154 (CD40 ligand) expression in response to viral antigens, can help to overcome some of the limitations of functional assays and restrictions of multimer-based methods. This and other current established methods for the detection of HCV-specific CD4(+) T cells will be discussed in this review.
authors.affiliation: Hepatology, Department of Clinical Research, University of Bern , Bern , Switzerland.
authors.forename: Megha U
authors.initials: MU
authors.lastname: Lokhande
authors.affiliation: Department of Gastroenterology and Hepatology, University Hospital of Freiburg , Freiburg , Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Thimme
authors.affiliation: NIHR Biomedical Research Centre, Oxford and Peter Medawar Building for Pathogen Research, University of Oxford , Oxford , UK.
authors.forename: Paul
authors.initials: P
authors.lastname: Klenerman
authors.affiliation: Hepatology, Department of Clinical Research, University of Bern , Bern , Switzerland ; Department of Hepatology, University Clinic of Visceral Surgery and Medicine , Inselspital, Bern , Switzerland.
authors.forename: Nasser
authors.initials: N
authors.lastname: Semmo
keywords: CD154; CD4 T cells; ELISpot; FACS; hepatitis C; tetramers; viral hepatitis