VEGF stands for vascular endothelial growth factor, which is a substance that promotes blood vessel growth. An antibody is a special kind of protein in the immune system, with receptors that attach to a specific harmful particle, or antigen. A VEGF antibody has receptors that bind to VEGF, preventing it from functioning normally. VEGF helps tumors grow by increasing their blood supply, and a VEGF antibody can be used to treat cancer by blocking this effect. The drug bevacizumab is a VEGF antibody used in the treatment of breast cancer.
In the growth of cancers, VEGF plays an important role by stimulating the development of blood vessels supplying oxygen and nutrients to tumors. The VEGF antibody bevacizumab binds to the part of VEGF which normally attaches to receptors on the surfaces of endothelial cells. Endothelial cells line blood vessels, and when VEGF binds to them it triggers changes causing them to multiply, ultimately leading to the formation of new blood vessels. VEGF is prevented from binding to endothelial cells when a VEGF antibody is attached to its binding site, so blood vessel growth is inhibited and tumor growth is reduced.
When a VEGF antibody, in the form of bevacizumab, is used to treat cancer, it is normally infused into a vein. The treatment may be given together with chemotherapy, and doses are administered at intervals of two or three weeks. Side effects may occur and these can include tiredness, nausea, diarrhea and raised blood pressure. Occasionally, patients experience a reaction to the infusion, with a rash, fever, swelling and wheezing, but this can often be treated simply by stopping the procedure.
The drug bevacizumab is an example of a monoclonal antibody, a single type of antibody produced commercially by an antibody production company. Monoclonal antibodies are produced by only one line of B cells in the immune system, while polyclonal antibodies are the products of more than one kind of B cell. Bevacizumab is also an example of an unconjugated antibody, which is not joined to another substance such as a drug, cancer-destroying agent or radioactive material.
Antibody conjugation is sometimes carried out by companies in order to create guided missiles, consisting of an antibody and a toxic material. The antibody delivers the destructive substance directly to a target such as a cancer cell, reducing its effect on healthy cells. Companies may research antibodies, develop them for therapeutic use and carry out antibody production on a large scale. Such antibody suppliers may offer a range of antibodies in an antibody catalog, or they may create custom products.