title: Autologous lymphoma vaccines induce human T cell responses against multiple, unique epitopes.
abstract: The clonotypic surface Ig receptor expressed by malignant B cells, idiotype, is a tumor-specific antigen and an attractive target for active immunotherapy. While Ab's specific for tumor idiotype have been well described in patients with B cell malignancies, the precise antigenic epitopes in human idiotype recognized by autologous T cells remain largely unknown. We report here that T cell lines generated from lymphoma patients actively immunized with idiotype protein specifically recognized multiple, unique immunodominant epitopes in autologous tumor idiotype. Synthetic peptides corresponding to hypervariable, but not framework, regions of Ig heavy chain specifically stimulated CD4(+) and CD8(+) T cells to proliferate and secrete proinflammatory cytokines in an MHC-associated manner. Detailed analysis revealed a minimal determinant of an immunodominant epitope, comprising critical residues at the amino terminus that may be a product of somatic hypermutation. Association of idiotype-specific T cell responses with previously documented molecular remissions in idiotype-vaccinated patients suggests that the newly identified T cell epitopes may be clinically relevant. Such antigenic epitopes may serve as candidates for novel peptide-vaccine strategies, and as tools to selectively expand tumor antigen-specific T cells for adoptive immunotherapy and for monitoring T cell immunity in vaccinated patients.
authors.affiliation: Basic Research Program, SAIC-Frederick Inc., National Cancer Institute at Frederick, National Institutes of Health, Maryland, 21702, USA. baskar@ncifcrf.gov
authors.forename: Sivasubramanian
authors.initials: S
authors.lastname: Baskar
authors.forename: Carol B
authors.initials: CB
authors.lastname: Kobrin
authors.forename: Larry W
authors.initials: LW
authors.lastname: Kwak
mesh_terms: D000595:Amino Acid Sequence; D000951:Antigens, Neoplasm / Q000235:genetics; D001324:Autoantigens / Q000235:genetics; D019496:Cancer Vaccines / Q000235:genetics / Q000276:immunology* / Q000494:pharmacology*; D002460:Cell Line; D006801:Humans; D016056:Immunodominant Epitopes / Q000235:genetics; D007130:Immunoglobulin Idiotypes / Q000235:genetics; D016219:Immunotherapy, Adoptive; D008213:Lymphocyte Activation; D008224:Lymphoma, Follicular / Q000235:genetics / Q000276:immunology* / Q000628:therapy*; D008969:Molecular Sequence Data; D015166:Monitoring, Immunologic; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000951:Antigens, Neoplasm; D001324:Autoantigens; D019496:Cancer Vaccines; D016056:Immunodominant Epitopes; D007130:Immunoglobulin Idiotypes