title: Radioimmunoassays for the C-terminus of prothymosin alpha and the N-terminus of parathymosin alpha for the measurement of the levels of alpha-thymosins in human cancer.
abstract: A radioimmunoassay specific for the C-terminus of human prothymosin alpha was developed using the synthetic peptide [Cys-Aca degrees]-human prothymosin alpha (90-109)-OH coupled to KLH as antigen and the analogue [Tyr-Aca degrees]-human prothymosin alpha (90-109)-OH labelled with 125I as tracer. The radioimmunoassay measured intact prothymosin alpha, in the range of 2-100 pmol and does not cross-react with the partly homologous polypeptide parathymosin alpha. A major epitope was located in the segment 95-107. A radioimmunoassay specific for the N-terminus of human parathymosin alpha, also measuring intact parathymosin alpha in the range of 1-20 pmol and not cross-reacting with prothymosin alpha, was developed using the synthetic peptide [Cys-Aca degrees]-human parathymosin alpha (1-30)-OH as antigen coupled to KLH and the analogue [Tyr-Aca degrees]-human parathymosin alpha (1-10)-OH labelled with 125I as tracer. A major epitope was located in the segment 1-10. These radioimmunoassays, together with a previously established radioimmunoassay for the N-terminus of prothymosin alpha, permitted the identification of the molecular forms of the cross-reactive materials in both normal and neoplastic breast tissue extracts as intact prothymosin alpha and parathymosin alpha. It was also possible to reveal significantly higher levels of both alpha-thymosins in breast cancer tissue compared to the nearby healthy tissue--the mean of 14 samples was over 14-fold higher--suggesting a role of both prothymosin alpha and parathymosin alpha in cell proliferation. The reported radioimmunoassays are expected to facilitate the search for prognostic and/or diagnostic applications of these polypeptides in human cancer.
authors.affiliation: Zoological Laboratory, Faculty of Science, University of Athens, Greece.
authors.forename: O E
authors.initials: OE
authors.lastname: Tsitsiloni
authors.forename: E
authors.initials: E
authors.lastname: Heimer
authors.forename: A
authors.initials: A
authors.lastname: Felix
authors.forename: P P
authors.initials: PP
authors.lastname: Yialouris
authors.forename: J
authors.initials: J
authors.lastname: Vamvoukakis
authors.forename: W
authors.initials: W
authors.lastname: Voelter
authors.forename: A A
authors.initials: AA
authors.lastname: Haritos
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000595:Amino Acid Sequence; D000818:Animals; D001943:Breast Neoplasms / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D003429:Cross Reactions / Q000276:immunology; D000939:Epitopes / Q000276:immunology; D005260:Female; D006801:Humans; D008875:Middle Aged; D008969:Molecular Sequence Data; D010455:Peptides / Q000032:analysis / Q000138:chemical synthesis; D011498:Protein Precursors / Q000032:analysis* / Q000138:chemical synthesis / Q000276:immunology; D011817:Rabbits; D011863:Radioimmunoassay / Q000379:methods*; D000077596:Thymalfasin; D013947:Thymosin / Q000031:analogs & derivatives* / Q000032:analysis / Q000138:chemical synthesis / Q000276:immunology
chemical_list: D000939:Epitopes; D010455:Peptides; D011498:Protein Precursors; C040782:prothymosin alpha; D013947:Thymosin; C044498:parathymosin alpha; D000077596:Thymalfasin