title: Polyclonality and multispecificity of the CTL response to a single viral epitope.
abstract: The molecular anatomy of an immunodominant, Ld restricted CTL epitope located between residues 28-39 in hepatitis B surface Ag was defined to explore the immunologic constraints on mutational escape from the CTL response during a viral infection. Using a panel of hepatitis B surface Ag residue 28-39-specific CTL clones, the response to this epitope was found to be extremely diverse at the level of TCR fine specificity and beta-chain usage. Although each clone recognized shared as well as unique residues within the epitope as TCR contact sites, even the shared residues were recognized differently by different TCRs. Despite these differences, all clones were comparably cytolytic following Ag stimulation and produced similar amounts of antiviral cytokines previously shown to inhibit HBV replication. These results demonstrate that the CTL response to individual viral epitopes can be markedly polyclonal and multispecific, such that mutational inactivation of a single TCR contact site will not usually lead to viral escape from all CTL clones of the same epitope specificity. Given these constraints and the fact that the CTL response is usually directed against several different epitopes during most viral infections, mutational inactivation of a single epitope is not likely to be sufficient to cause viral persistence.
authors.affiliation: First Department of Internal Medicine, Research Center for Infectious Disease, Aichi Medical University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Ishikawa
authors.forename: D
authors.initials: D
authors.lastname: Kono
authors.forename: J
authors.initials: J
authors.lastname: Chung
authors.forename: P
authors.initials: P
authors.lastname: Fowler
authors.forename: A
authors.initials: A
authors.lastname: Theofilopoulos
authors.forename: S
authors.initials: S
authors.lastname: Kakumu
authors.forename: F V
authors.initials: FV
authors.lastname: Chisari
mesh_terms: D019943:Amino Acid Substitution / Q000276:immunology; D000818:Animals; D000956:Antigens, Viral / Q000276:immunology* / Q000378:metabolism; D001667:Binding, Competitive / Q000276:immunology; D002999:Clone Cells; D003601:Cytotoxicity Tests, Immunologic; D018984:Epitopes, T-Lymphocyte / Q000276:immunology* / Q000378:metabolism; D006183:H-2 Antigens / Q000378:metabolism; D006514:Hepatitis B Surface Antigens / Q000276:immunology* / Q000378:metabolism; D012515:Mast-Cell Sarcoma; D051379:Mice; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000276:immunology / Q000378:metabolism; D011485:Protein Binding / Q000276:immunology; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000037:antagonists & inhibitors / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D014407:Tumor Cells, Cultured
chemical_list: D000956:Antigens, Viral; D018984:Epitopes, T-Lymphocyte; D006183:H-2 Antigens; D006514:Hepatitis B Surface Antigens; D010455:Peptides; D016693:Receptors, Antigen, T-Cell, alpha-beta