Antibodies and peptide antigens for producing antibodies having a selective binding specificity to bioactive intact parathyroid hormone (PTH) 1-84

Abstract

Peptide antigens corresponding to amino acid residues 2-12, 1-12, 2-15 and 1-15 of parathyroid hormone (PTH), antibodies having an affinity to such peptide antigens and methods of producing the same. Such antigens, antibodies and methods producing the same according to the present invention are useful in determining bioactive intact PTH levels in serum, plasma, and/or cell culture media. Such antibodies further possess a high degree of species cross-reactivity, but substantially mitigated cross-reactivity to non-whole PTH peptide fragments and little to no recognition of the first amino acid residue of PTH.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] (Not Applicable) STATEMENT RE: FEDERALLY SPONSORED RESEARCH / DEVELOPMENT [0002] (Not Applicable) BACKGROUND OF THE INVENTION [0003] Parathyroid hormone (PTH) and its importance in regulating the concentration of calcium ions in the blood is well-known. In this regard, such hormone is created by the parathyroid glands and, in combination with other factors, functions to regulate the blood calcium ion levels such that the same is maintained in a steady concentration in both cells and surrounding fluids. Essentially, PTH functions to release stored calcium in the body when serum calcium levels decrease. On the other hand, such secretion is suppressed to the extent the serum calcium concentration increases. [0004] In its complete form PTH comprises a unique peptide comprised of 84 amino acids. The specific sequence of PTH, as provided for a plurality of species, namely, humans, rats, mice, bovids, dogs and pigs, are depicted in FIG. 1, and a...

AI Technical Summary

Benefits of technology

[0015] Another object of the present invention is to provide novel antigens for the production of antibodies, antibodies and methods of producing antibodies that have a greater affinity and specificity for PTH than prior art binding partners and further, possess a higher degree of cross reactivity between inter-species PTH such that the antigens, antibodies and methods producing the same according the present invention can be readily utilized for the detection of PTH in a variety of species.

[0016] Another object of the present invention is to provide novel antigens for the production and isolation of antibodies, antibodies and methods of producing antibodies which have a binding affinity and specificity for more of the biologically active N-terminal portion of PTH and, hence, are more effective and accurate in determining bioactive intact PTH levels than prior art binding partners directed thereto.

Problems solved by technology

Notwithstanding its important role in metabolism and clinical significance, substantial difficulties have and continue to exist with regard to determinating circulating biologically active PTH levels.

Furthermore, it is known that the PTH peptide can be present in a variety of circulating PTH fragments, and in particular large non-(1-84) circulating PTH fragments which appear to co-migrate chromatographically with the (7-84) PTH molecule and are known to significantly interfere with conventional PTH assay measurements.

However, to derive such antibodies requires substantial effort and expense in purifying the same.

Moreover, such tracer antibodies have maximum recognition for only the first amino acid residue of PTH, and substantially reduced specificity for any subsequent residues thus obviating its use for some other species where the first amino acid is different.

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