title: Induction of T cells specific for the mutated segment of oncogenic P21ras protein by immunization in vivo with the oncogenic protein.
abstract: Many malignancies harbor mutated ras proto-oncogenes encoding 21 kDa proteins with single amino acid substitutions. Previous studies have shown that the aberrant p21ras proteins are potential tumor-specific antigens in that CD4+ class II major histocompatibility complex-restricted T cells specific for the mutated segment of various oncogenic p21ras proteins can be elicited by immunization in vivo with synthetic peptides corresponding to the mutated segment. T-cell recognition of an antigenic peptide within a protein may be influenced substantially, either positively or negatively, by flanking amino acid sequences as well as by more distal immunogenic or tolerogenic epitopes within the same protein. This study examined whether T cells specific for the mutated segment of an oncogenic p21ras protein can be elicited by immunization in vivo with the protein. The results showed that p21ras protein bearing the transforming single amino acid substitution of leucine for glutamine at residue 61 could elicit T cells specifically reactive to the mutated region of the protein in C3H/HeN mice. Thus, an abnormal p21ras protein specifically associated with malignant transformation can be immunogenic in vivo. These results predict that in some circumstances, mutated p21ras proteins expressed by malignancies might elicit detectable mutation-specific T-cell responses.
authors.affiliation: Department of Medicine, University of Washington, Seattle.
authors.forename: D J
authors.initials: DJ
authors.lastname: Peace
authors.forename: J W
authors.initials: JW
authors.lastname: Smith
authors.forename: M L
authors.initials: ML
authors.lastname: Disis
authors.forename: W
authors.initials: W
authors.lastname: Chen
authors.forename: M A
authors.initials: MA
authors.lastname: Cheever
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002455:Cell Division / Q000276:immunology; D002460:Cell Line; D000939:Epitopes; D005260:Female; D007114:Immunization; D051379:Mice; D008809:Mice, Inbred C3H; D008969:Molecular Sequence Data; D009154:Mutation; D015689:Oncogene Protein p21(ras) / Q000235:genetics / Q000276:immunology*
chemical_list: D000939:Epitopes; D015689:Oncogene Protein p21(ras)