Every cell in the body has a signature set of proteins that allow one cell to distinguish itself from another, much like the shared facial or skin features common to ethnic groups. Some of these signature proteins, known as receptors, are found on the cell’s surface and can be detected by using antibodies that match up to specific receptors. To locate stem cells amid millions of other cell types, scientists must know which receptors are exclusive to the rare cell and not present on others. Radiology researcher Sridhar Nimmagadda, Ph.D., is testing methods to tag cancer stem cells with their own signature of antibodies and radiolabel them to be visible on combined PET/CT scanners. He says the technique also has the potential to allow study of embryonic stem cells as long as scientists could identify the cells’ signature receptors.
Nimmagadda’s technique also employs a modified antibody that binds to two different receptors on the same cell, simultaneously. He says the double-binding strategy could increase specificity for locating stem cells in the body in addition to generating a long-lasting signal, as opposed to if a mono-specific antibody is used. Overall, these methods could increase both specificity and sensitivity for locating stem cells in the body.
--by Vanessa Wasta