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: O E Tsitsiloni, E Heimer, A Felix, P P Yialouris, J Vamvoukakis, W Voelter, A A Haritos
• Journal: Journal of immunological methods (J Immunol Methods) Vol. 169 Issue 2 Pg. 163-71 (Mar 10 1994) ISSN: 0022-1759 [Print] Netherlands
• PMID: 7510758 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Epitopes
• Peptides
• Protein Precursors
• prothymosin alpha
• Thymosin
• parathymosin alpha
• Thymalfasin

Topics

• Aged
• Aged, 80 and over
• Amino Acid Sequence
• Animals
• Breast Neoplasms (chemistry)
• Chromatography, High Pressure Liquid
• Cross Reactions (immunology)
• Epitopes (immunology)
• Female
• Humans
• Middle Aged
• Molecular Sequence Data
• Peptides (analysis, chemical synthesis)
• Protein Precursors (analysis, chemical synthesis, immunology)
• Rabbits
• Radioimmunoassay (methods)
• Thymalfasin
• Thymosin (analogs & derivatives, analysis, chemical synthesis, immunology)