Sharper weapons against tumor cells
American researchers have developed a method that could improve the use of monoclonal antibodies in cancer therapy.
The researchers led by Greg Lazar from the California-based biotechnology company Xencor have found a process that can increase the toxic effect of certain antibodies on cancer cells tenfold. For this purpose, the scientists specifically modified the "constant", so-called FC region of the immunoglobulins.
The FC region of antibodies does not recognize the antigens themselves, but after the antibody has docked to its target, it activates further defense measures - such as the so-called antibody-dependent cell-mediated Cytotoxicity (ADCC), which allows the organism to lyse tumor cells. In the experiments, the researchers partially doubled the activities of the ADCC by modifying the FC region.
The modified antibodies can also target previously unassailable cancer cells that only reveal themselves through a very small amount of typical antigens, the researchers hope.
The high precision with which these proteins recognize antigens has been used to detect and visualize the causes of diseases for some time now. To do this, a weakly radioactive substance is attached to the antibody. A target region targeted by the antibody can then be localized on later X-ray images. This is used, for example, to locate and attack tumors in the body. However, only certain antibodies have so far been suitable for this purpose, many others have proven to be too ineffective.
