New research, carried out by NPL, the University of Edinburgh and industrial partners Mologic Ltd, IBM Watson Research Center and Pepscan Presto BV, sheds light on the way antibodies distinguish between different but closely related 'biomarkers' - proteins which reveal information about the condition of the human body. The results could be used to develop new technologies for quickly diagnosing and treating fatal diseases such as cancer.

The turn-like structure of human
chorionic gonadotropin epitope

All diseases have proteins, or concentrations of proteins, specifically linked to them called biomarkers, and identifying these can prove a powerful diagnostic tool.

Antibodies can be used to test for specific biomarkers because they only bind to specific molecules or groups of molecules. Problems can arise when they bind to groups of similar molecules, leading to false positives and unreliable information.

This research focused on hCG (human chorionic gonadotropin), a hormone produced during pregnancy. A subunit of hCG - hCGβ - is secreted by some cancers, meaning its detection can give early warning of tumours.

The antibodies bind to a tiny part of the hormone called an epitope. Hormones are made up of thousands of 'building blocks', with epitopes making up less than 10 of these blocks.

The difference between hormones can be as little as one of these epitope blocks.

hCG is very similar to other hormones, known as LH and FSH, which are always present in the body, and can be confused with these other hormones during testing, leading to unreliable results.

This research showed how very subtle, atomic level characteristics define the antibody selectivity of different proteins. It identified that certain antibodies are highly selective and can distinguish between hCGβ and the closely related LH hormone during testing.

This will enable development of further tests to identify other biomarkers from similar groups. Pharmaceutical companies could use this to develop new diagnostic technologies and clinical disease treatments, e.g. tests for tumours as part of routine screenings.

Max Ryadnov, Principal Research Scientist at NPL, said:

"This work answers one of the big questions in distinguishing biomarkers which are critical for identifying and treating serious diseases. We hope this breakthrough will underpin the development of a range of new diagnostic techniques and treatment."

Prof Paul Davis, Chief Scientific Officer of Mologic Ltd, said:

"It was a great collaborative effort, and it stands as a fine example of what can be achieved when motivated scientists work together openly across boundaries."

Read the full paper published in the Journal of Biological Chemistry: Antibody Recognition of a human chorionic gonadotropin epitope (hCG{beta}66-80) depends on local structure retained in the free peptide

Find out more about NPL's work in Biotechnology

For more information, please contact Max Ryadnov