title: Identification of a CD4 T-cell epitope in tumor rejection antigen RLakt on BALB/c radiation-leukemia RL male 1.
abstract: We have previously shown that the RLakt antigen was predominantly recognized by CD8 cytotoxic T lymphocytes (CTL) in RL male 1-bearing or -rejected syngeneic BALB/c mice. CD8 CTL were directed to the octamer pRL1a peptide IPGLPLSL of which recognition was H-2L(d)-restricted. In this study, we identified a CD4 T-cell epitope peptide in the tumor rejection antigen RLakt on BALB/c radiation-leukemia RL male 1. Analyses of the recognition of a bulk CD4 T-cell line using several recombinant RLakt proteins suggested the presence of multiple CD4 T-cell epitopes in the molecule. However, cloning from a bulk CD4 T-cell line resulted in only two clones from 200 wells seeded at three cells per well, and those two CD4 T-cell clones recognized the same epitope peptide in RLakt. The epitope peptide was 14-mer p12-25, AYREETLSIIPGLP, and its recognition was H-2IA(d)-restricted. This sequence overlapped with the CD8 T-cell epitope pRL1a in its N-terminal 5 amino acid residues. The relationship of the epitope to the pRL1a peptide predominantly recognized by CD8 CTL suggests that the 14-mer epitope is predominantly recognized by CD4 T-cells.
authors.affiliation: Department of Immunology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikaya-Cho, Okayama, Japan.
authors.forename: Savas
authors.initials: S
authors.lastname: Kaya
authors.forename: Akiko
authors.initials: A
authors.lastname: Uenaka
authors.forename: Shuichiro
authors.initials: S
authors.lastname: Sato
authors.forename: Toshiro
authors.initials: T
authors.lastname: Ono
authors.forename: Toshiki
authors.initials: T
authors.lastname: Aji
authors.forename: Eiichi
authors.initials: E
authors.lastname: Nakayama
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002460:Cell Line; D018984:Epitopes, T-Lymphocyte; D005260:Female; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D007953:Leukemia, Radiation-Induced / Q000276:immunology*; D008213:Lymphocyte Activation; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D050378:T-Lymphocytes, Regulatory / Q000276:immunology
chemical_list: D000951:Antigens, Neoplasm; D018984:Epitopes, T-Lymphocyte; D000949:Histocompatibility Antigens Class II