Flow cytometric analysis of peptide binding to major histocampatibility complex class I for hepatitis C virus core T-cell epitopes

Background/Methods: To characterize the repertoire of T-cell epitopes on th e hepatitis C virus (HCV) core protein, we studied major histocompatibility complex (MHC) class I binding of 75 decapeptides on 20 human B-cell lines and murine spleen cells using a flow cytometric assay. The results were com pared with MHC class I stabilization on T2 cells, the SYFPEITHI algorithm, and known T-cell epitopes from the literature. Results: Binding of peptides proved to be specific for MHC class I molecule s. We observed peak fluorescence signals at positions amino acids (aa) 35-4 4, aa 87-96, aa 131-140, and aa 167-176 in virtually all HLA-A2-positive ce ll Lines. These sites corresponded to T-cell epitopes predicted by SYFPEITH I and the positions of known T-cell epitopes, whereas T2 stabilization was at variance for two peptides. The assay was applied to HLA-A2-negative cell s and murine spleen cells without further modification, and identified addi tional peptides, corresponding to known T-cell epitopes. Conclusions: Peptide binding to different MHC class I alleles can be mapped rapidly by a now cytometric assay and enables a first orientation on the s ites of possible T-cell epitopes. Application of this assay to HCV core sug gests a rather Limited repertoire of epitopes in the Caucasoid population. Cytometry 41:271-278, 2000. (C) 2000 Wiley-Liss, Inc.