Immune system that is widely dispersed throughout the tissues in our body fights various viral and bacterial infections and is highly complex.
It basically comprises macrophages, lymphocytes, pathogenic cells and antibodies. Our immune system plays a very important role to prevent the growth and kill cancer cells. Some types of cancer occur when our immune system fails to perform this function.
Immunotherapy refers to using body’s own immune system to treat cancer.
Immunotherapy is at an investigational level in most of the medical centers around the world.
Biological response modifiers are substances used in immunotherapy that are involved in development of cancer and other diseases through body’s natural and biological response.
Interferon
Interferon is produced in response to a viral infection by the host and was the first substance described that can inhibit the spread of virus in the body.
Interferon is also believed to have anticancer effects which can be related to changes in function of immune system. There are various interferons and are mainly divided into three classes – Interferon alpha – produced on stimulation of a virus by lymphocytes. Interferon beta – produced on stimulation of a virus by fibroblast cells. Interferon gamma - produced on immune stimulation by lymphocytes. The liquid around the bacteria is the main source of interferon for the drug companies that use interferon as a cancer immunotherapeutic agent. The anti-cancer effects of interferon are variable for different patients and different cancers.
Before receiving this treatment, it is important for a person to confirm with a specialist about its effectiveness in a particular type of cancer.
Currently interferon is the best known example of biological-response modifiers others include –
Bacillus Calmette-Guerin (BCG) vaccine is used occasionally to prevent re growth of bladder cancer and sometimes used to control recurrent malignant melanoma. However laboratory studies and evaluation does not prove BCG as a powerful anti-cancer agent.
Monoclonal antibodies can be used in future therapeutically to carry drugs to specific body sites and determine the location of the tumor. Interleukin-2 is a biological substance under experiments in regards to its capacity to alter various concepts of normal immunity. It may have the ability to support some lymphocyte growth and stimulate a substance called lymphokine-activated killer cells that can attack tumor cells. Interleukin-2 has similar properties to that of interferon that stimulates the subset of tumor killer cells.
Patients can receive interleukin-2 in high doses intravenously or it can also be re-infused after exposure to patients own lymphocytes.
