The Biochemical Society is 100 years old this year. To celebrate, they have prepared a list of the most important discoveries. Like lists of the best books or the best films, the joy is not in the result but in the discussion. In their “what did we miss section”, I added antibodies. I love antibodies. Well actually that’s probably over stating the case a bit, but I think antibodies are cool. Remember, I am a nerd so it’s OK for me to think that molecules are cool.
Why do I think antibodies are cool?
Well firstly, they help to keep you, me, and our families, alive. Antibodies are proteins made by our white blood cells that bind bacterias and viruses and help us to clear them from our bodies. Most vaccines depend on a good antibody response to work. In order to measure my vaccination against hepatitis, my antibody levels were measured.
Secondly, antibodies are some of the most sensitive things in the world. After they are made, antibodies undergo a process called “affinity maturation”. This basically means they get better and better. This sensitivity is caused by small changes in the DNA that makes the antibody and then a test for the strength of the antibody to the virus. The good antibodies are encouraged the poor ones ignored….
Thirdly, antibodies are incredibly specific. They typically recognise just 8 to 10 amino acids. This means a chain of about 30 carbon and nitrogen molecules. If you change even the order these amino acids, the antibodies don’t work any more. This specificity is also remembered. So your antibodies remember a small peptide sequence from a virus they met years ago.
The combination of specificity and sensitivity makes antibodies very useful in the laboratory. They are used for clinical diagnosis and for cutting edge research. Using an antibody we can detect very small amounts of proteins on the surface of cells. As was lyrically described during a collaboration with an artist and a poet, we use them to “seed our cells with light”.
Finally, as if all that wasn’t enough, antibodies are a great example of science2therapy. I have described herceptin previously. Herceptin is an antibody against a growth factor receptor that is used to treat breast cancer. The first antibody to really make a difference to clinical treatment was ritiximab, an antibody against a B-cell molecule called CD20. Rutiximab is now routinely used for the treatment of Non-Hodgkin’s lymphoma and chronic lymphocytic leukaemia.
The usefulness of antibodies in the clinic is prompting the development of many different antibodies. They are useful for targeting molecules on the surface of cells. An interesting Perspective article from Nature Drugs Discovery (payment required), showed a graph with an exponential growth of the number of antibodies in clinical development.
For me, antibodies are a science2therapy example of how science has already delivered, continues to deliver and will continue to deliver in the future. Optimistic days for a cool little molecule that inside all of us :-)
A few interesting facts:
Antibodies are small (about 12 nanometers). There is a very nice graphic here about scale.
In 1984, the Nobel Prize in Physiology or Medicine was awarded jointly to Niels K. Jerne, Georges J.F. Köhler and César Milstein “for theories concerning the specificity in development and control of the immune system and the discovery of the principle for production of monoclonal antibodies”.
Last year, the US market spent $2.2 billion on Rituxin, the brand name for rituximab, according to this report by the IMS Institute for Healthcare Informatics.