Antibodies are molecules that evolved as part of the immune system, attaching themselves to microorganisms and then presenting the microorganisms to white blood cells for destruction.
Now researchers at XOMA Corporation and the University of San Francisco in the United States are studying antibodies that attach themselves to insulin receptors in cells to help insulin to do its job. Insulin receptors have been compared to locks that are opened by insulin acting as a key. Insulin is then able to help sugar enter cells, where it can be broken down and used for energy. In Type 2 diabetes, for complex reasons, cells become resistant to insulin and sugar then stays outside the cells in the bloodstream. Blood sugar levels rise and damage blood vessels and certain organs, while muscles and some other organs are unable to produce enough energy to carry on normal healthy functions.
In February 2014, PLoS One reported improved use of sugar by cells in the presence of an antibody named XMetS. XMetS attaches itself to insulin receptors on outer cell membranes, much as other antibodies attach themselves to disease-causing microorganisms. Under the influence of this antibody, cells become better able to respond to insulin, allowing sugar molecules to enter and become fuel.
Antibody treatment is far from being tested on diabetic human beings, but the present state of knowledge shows promise. It is thought antibody therapy will not have any danger of causing hypoglycemia, or low blood sugar levels, as insulin and many oral medications can.
Antibodies, or immunoglobulins, are Y-shaped proteins produced by white cells called B plasma cells, or lymphocytes, a kind of white blood cell. Each of the two top points of the Y has a structure that attaches the antibody to another molecule, called an antigen. Antigens are usually protein molecules the body recognizes as foreign invaders. Antigens are commonly found on the surface of bacteria and viruses. When an antibody attaches itself to an antigen, the antibody’s other end can attach to a macrophage, another type of white cell, which then proceeds to eat the antigen-antibody complex. (“Macrophage” means “large eater”). Antibodies are often given in immunizations, or antigens may be given to induce the body’s own immune system to make new antibodies.
When an antibody attaches itself to an insulin receptor on a cell membrane, the receptor is playing the part of an antigen. XMetS, of course, is designed not to attract macrophages.
Antibody therapy for clinical use is years in the future, but isn’t it great to know techniques that would have been science fiction in the past are actually beginning to show promise