Antibodies are naturally used by the body to bind targets on pathogens and neutralize them, and these specific interactions have been used in the biomedical research community in many ways. Antibodies that are linked to a marker, such as a fluorescent tag, can be used to bind to a specific protein and enable scientists to visualize the protein in a microscope, for example. Now scientists have found a way to use antibodies to trigger chemical reactions in very specific ways; the work has been reported in Nature Communications.
The idea is that a specific chemical reaction will only take place when a certain antibody is present.
"We demonstrated a strategy to use specific antibodies to control chemical reactions forming a wide range of molecules, from imaging to therapeutic agents." said the senior study author, Francesco Ricci, a professor at the University of Rome, Tor Vergata. "Our approach allows to synthesize a functional molecule from inactive precursors only when a specific antibody is present in the reaction mixture."
In this study, the researchers also utilized a synthetic molecule based on another biomolecule called oligonucleotides. These are made of the nucleotides that compose DNA, and interactions between them also happen in very specific ways because of the particular ways that DNA sequences interact.
"Synthetic oligonucleotides are amazing molecules, they can be modified with a range of reactive groups and also with recognition elements that can target specific antibodies," explained first study author Lorena Baranda, a graduate candidate in the Ricci lab. "In our work we rationally designed and synthesized a pair of modified DNA sequences that can recognize a specific antibody and bind to it. When this happens the reactive groups appended on the other ends of the DNA strands will be in close proximity and their reaction will be triggered ultimately leading to the formation of a chemical product."
One application for this research, for example, is the regulation of how functional molecules are formed. The scientists demonstrated this by generating an anticoagulant drug; it works by inhibiting an enzyme called thrombin, which is key to blood coagulation.
"We demonstrated that a specific IgG antibody can trigger the formation of the anticoagulant agent, which was further proven to efficiently inhibit the activity of thrombin," said Ricci. "The strategy is highly specific to the antibody of interest and also programmable. We envision it would represent a new avenue to targeted therapy and diagnostics."