16 Aug Immunotherapy
What is immunotherapy?
Immunotherapy is a standard treatment for some types of cancer, for example melanoma that has spread. And it is in trials for other types of cancer.
What it is
Immunotherapy uses our immune system to fight cancer. It works by helping the immune system recognise and attack cancer cells.
Some types of immunotherapy are also called targeted treatments or biological therapies.
You might have immunotherapy on its own or with other cancer treatments.
The immune system
Our immune system works to protect the body against infection, illness and disease. It can also protect us from the development of cancer.
The immune system includes the lymph glands, spleen and white blood cells. Normally, it can spot and destroy faulty cells in the body, stopping cancer developing. But a cancer might develop when:
- the immune system recognises cancer cells but it is not strong enough to kill the cancer cells
- the cancer cells produce signals that stop the immune system from attacking it
- the cancer cells hide or escape from the immune system
Types of immunotherapy
Cancer treatments do not always fit easily into a certain type of treatment. This is because some drugs or treatments work in more than one way and belong to more than one group. So you might hear the same drug or treatment called different things.
For example, a type of immunotherapy called checkpoint inhibitors are also described as a monoclonal antibody or targeted treatment.
There are different types of immunotherapy:
Monoclonal antibodies (MABs)
MABs recognise and attach to specific proteins on the surface of cancer cells.
Antibodies are found naturally in our blood and help us to fight infection. MAB therapies mimic natural antibodies, but are made in a laboratory. Monoclonal means all one type. So each MAB therapy is a lot of copies of one type of antibody.
MABs work as an immunotherapy in different ways. They might do one of the following:
- trigger the immune system
- help the immune system to attack cancer
MABs trigger the immune system by attaching themselves to proteins on cancer cells. This makes it easier for the cells of the immune system to find and attack the cancer cells. This process is called antibody dependent cell mediated cytotoxicity (ADCC).
Checkpoint inhibitors are MABs that work by helping the immune system attack cancer cells. Cancer can sometimes push a stop button on the immune cells, so the immune system won’t attack them. Checkpoint inhibitors block cancers from pushing the stop button.
Different drugs block different checkpoint proteins, such as CTLA-4, PD-1 and PD-L1. So you might also hear these drugs called CTLA-4 inhibitors, PD-1 inhibitors or PD-L1 inhibitors.
Vaccines to treat cancer
Researchers are looking at whether vaccines can be used as a treatment to help the immune system to recognise and attack cancer cells.
Normally, vaccines help to protect us from disease. They are made from weakened or harmless versions of the disease they are being made to protect us from. This means that they don’t cause the disease.
When you have the vaccine, it stimulates the immune system into action. The immune system makes antibodies that can recognise and attack the harmless versions of the disease. Once the body has made these antibodies it can recognise the disease if you come into contact with it again. So you’re protected from it.
Researchers are also testing vaccines to treat cancer. In the same way that vaccines work against diseases, the vaccines are made to recognise proteins that are on particular cancer cells. This helps the immune system to recognise and mount an attack against those particular cancer cells.
Cytokines are a group of proteins in the body that play an important part in boosting the immune system.
Interferon and interleukin are types of cytokines found in the body. Scientists have developed man made versions of these to treat some types of cancer.
Adoptive cell transfer
Adoptive cell transfer changes the genes in a person’s white blood cells (T cells) to help them recognise and kill cancer cells. Changing the T cell in this way is called genetically engineering the T cell.