title: In vitro selection of lymphocytic choriomeningitis virus escape mutants by cytotoxic T lymphocytes.
abstract: Cytotoxic T lymphocyte (CTL)-mediated cytolysis is induced via the interaction of the specific T-cell antigen receptor and the peptidic viral antigen associated with the major histocompatibility complex class I antigen. Here we demonstrate in vitro that lymphocytic choriomeningitis virus (LCMV) can escape the cytotoxic activity of LCMV-specific cloned CTLs by single amino acid changes within the recognized T-cell epitope defined by residues 275-289 of the LCMV glycoprotein [LCMV-GP-(275-289)]. LCMV-infected fibroblasts at a multiplicity of infection of 10(-3) exposed to virus-specific CTL at an effector-to-target cell ratio of 4:1 4 hr after infection was optimal for virus mutant selection. The selections were carried out with three LCMV-GP-(275-289)-specific CTL clones expressing T-cell antigen receptors containing the identical variable gene segments V alpha 4 and V beta 10 but different junctional regions; selection was also possible with LCMV-GP-(275-289)-specific cytotoxic polyclonal T cells. The most common escape mutation was an amino acid change of asparagine (AAT) to aspartic acid (GAT) at position 280; an additional mutation was glycine (GGT) to aspartic acid (GAT) at position 282. The results presented show that relevant point mutations within the T-cell epitope of LCMV-GP-(275-289) occur frequently and that they are selectable in vitro by CTLs.
authors.affiliation: Institute of Pathology, University Hospital, Zurich, Switzerland.
authors.forename: T
authors.initials: T
authors.lastname: Aebischer
authors.forename: D
authors.initials: D
authors.lastname: Moskophidis
authors.forename: U H
authors.initials: UH
authors.lastname: Rohrer
authors.forename: R M
authors.initials: RM
authors.lastname: Zinkernagel
authors.forename: H
authors.initials: H
authors.lastname: Hengartner
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002461:Cell Line, Transformed; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D004279:DNA, Viral / Q000235:genetics; D000939:Epitopes / Q000032:analysis; D014644:Genetic Variation; D008217:Lymphocytic choriomeningitis virus / Q000235:genetics* / Q000276:immunology / Q000302:isolation & purification; D046911:Macromolecular Substances; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D012367:RNA, Viral / Q000235:genetics; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D013539:Simian virus 40 / Q000235:genetics; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D004279:DNA, Viral; D000939:Epitopes; D046911:Macromolecular Substances; D009838:Oligodeoxyribonucleotides; D012367:RNA, Viral; D011948:Receptors, Antigen, T-Cell