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Studies from Free University Add New Findings in the Area of Sulfur Amino Acids (Site-Specific Labeling of Cysteine-Tagged Camelid Single-Domain...

July 1, 2014



Studies from Free University Add New Findings in the Area of Sulfur Amino Acids (Site-Specific Labeling of Cysteine-Tagged Camelid Single-Domain Antibody-Fragments for Use in Molecular Imaging)

By a News Reporter-Staff News Editor at Life Science Weekly -- Current study results on Sulfur Amino Acids have been published. According to news reporting from Brussels, Belgium, by NewsRx journalists, research stated, "Site-specific labeling of molecular imaging probes allows the development of a homogeneous tracer population. The resulting batch-to-batch reproducible pharmacokinetic and pharmacodynamic properties are of great importance for clinical translation."

The news correspondents obtained a quote from the research from Free University, "Came lid single-domain antibody-fragments (sdAbs)-the recombinantly produced antigen-binding domains of heavy-chain antibodies, also called Nanobodies-are proficient probes for molecular imaging. To safeguard their intrinsically high binding specificity and affinity and to ensure the tracer's homogeneity, we developed a generic strategy for the site-specific labeling of sdAbs via a thio-ether bond. The unpaired cysteine was introduced at the carboxyl-terminal end of the sdAb to eliminate the risk of antigen binding interference. The spontaneous dimerization and capping of the unpaired cysteine required a reduction step prior to conjugation. This was optimized with the mild reducing agent 2-mercaptoethylamine in order to preserve the domain's stability. As a proof-of-concept the reduced probe was subsequently conjugated to maleimide-DTPA, for labeling with indium-111. A single conjugated tracer was obtained and confirmed via mass spectrometry. The specificity and affinity of the new sdAb-based imaging probe was validated in a mouse xenograft tumor model using a modified clinical lead compound targeting the human epidermal growth factor receptor 2 (HER2) cancer biomarker. These data provide a versatile and standardized strategy for the site-specific labeling of sdAbs."

According to the news reporters, the research concluded: "The conjugation to the unpaired cysteine results in the production of a homogeneous group of tracers and is a multimodal alternative to the technetium-99m labeling of sdAbs."

For more information on this research see: Site-Specific Labeling of Cysteine-Tagged Camelid Single-Domain Antibody-Fragments for Use in Molecular Imaging. Bioconjugate Chemistry, 2014;25(5):979-988. Bioconjugate Chemistry can be contacted at: Amer Chemical Soc, 1155 16TH St, NW, Washington, DC 20036, USA. (American Chemical Society - www.acs.org; Bioconjugate Chemistry - www.pubs.acs.org/journal/bcches)

Our news journalists report that additional information may be obtained by contacting S. Massa, Vrije Univ Brussel, Univ Ziekenhuis Brussel, Dept. of Nucl Med, B-1090 Brussels, Belgium. Additional authors for this research include C. Xavier, J. De Vos, V. Caveliers, T. Lahoutte, S. Muyldermans and N. Devoogdt (see also Sulfur Amino Acids).

Keywords for this news article include: Antibodies, Europe, Belgium, Brussels, Cysteine, Immunology, Blood Proteins, Nanotechnology, Immunoglobulins, Molecular Imaging, Sulfur Amino Acids, Neutral Amino Acids, Sulfhydryl Compounds, Emerging Technologies

Our reports deliver fact-based news of research and discoveries from around the world. Copyright 2014, NewsRx LLC


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Source: Life Science Weekly


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