Immunotherapy strategies for disease challenges

Modern disease challenges include not only infectious disease but also increasing rates of cancer and autoimmune diseases. These have increased with the aging of our population and changes in our habits and environment.

Immunotherapies are medical treatments that take advantage of the patient’s own immune system to fight disease. Immunotherapies generally fall into two categories:

  • Stimulation: activating and enhancing immune responses
  • Suppression: blocking or limiting immune responses

Use this page to revise the following concepts within the immunotherapies strategies for disease challenges:

The development of monoclonal antibodies

The growing challenge of the identification, screening, and treatment of infectious diseases led to medical advancements such as the development of enzyme-linked immunosorbent assays (ELISAs) and rapid antigen tests (RATs) which are used to identify the presence and concentration of antigens or antibodies in a sample. Injections of identical copies of a specific antibody, called monoclonal antibodies (mAbs), are one of the only ways to currently treat the infectious disease Ebola. All of these tests and treatments require many, many identical copies of an antigen or antibody, which led to the development of mass-production methods for making mAbs. mAbs are now being used to treat many conditions including  cardiovascular disease, hypersensitivity responses such as allergies, autoimmune diseases, and cancer.

mAbs are created in a laboratory to replicate the antibodies naturally produced by the adaptive immune system in vertebrates. They are designed to bind to specific protein targets (called antigens) on the surface of cells or free in the body. mAbs can stimulate, suppress, or have no effect on the immune system. They can empower our innate and adaptive immune systems by making targets easier for white blood cells to locate and destroy or by neutralising a pathogenic cell or protein’s actions.

Producing monoclonal antibodies

In 1975, the development and mass production of mAbs using the hybridoma technique was a major breakthrough in immunology. Click the hotspots in the image below to see the general steps in producing mAbs.

Treating autoimmune diseases with monoclonal antibodies

Autoimmune diseases occur when the body's immune system attacks its own healthy cells and tissues. mAbs help treat autoimmune diseases by neutralising and reducing the numbers of:

  • specific proteins or cells that both trigger and perpetuate inflammation
  • specific immune system cells that are attacking the body’s own cells
  • B plasma cells producing autoantibodies targeting the body’s own cells

In the autoimmune disease Lupus, various B and T cells become overactive and the B plasma cells produce autoantibodies. The autoantibodies can lead to long-lasting tissue inflammation and damage to various organs. They can also be linked to pregnancy complications, stroke, heart attacks, and other blood clots.

Click on the image below to see how monoclonal antibodies help to treat Lupus.

Treating cancer with monoclonal antibodies

Cancer is caused by uncontrolled cell division and can form large masses of cancer cells called tumours. Apoptosis, or programmed cell death, is a series of molecular steps that cause a cell to die. It is a natural response to cell stress, and is used to get rid of old, damaged or unneeded cells. Apoptosis becomes blocked or evaded in cancer cells. Cancer cells also developed ways to avoid being found and targeted by immune system cells. Surgery and chemotherapy, the traditional cancer treatments, are both difficult and potentially dangerous, as they also damage healthy cells. Since cancer cells often have cancer-specific surface antigens which are not found on healthy cells, mAbs can provide a more targeted and precise treatment. mAbs can also be further personalised by using antigen samples of the patient's own tumour removed during an initial surgery.

mAbs can be used to treat cancer by either stimulating and enhancing the immune system’s natural targeting of cancerous cells, suppressing the actions of pro-tumour cells, or delivering radioactive substances, drugs and toxins to selectively damage the cancer cells. All these strategies eventually result in the death of the cancer cells through apoptosis.

There are two types of mAbs used against cancer:

  1. Naked mAbs that work directly on cancerous cells or by stimulating the immune response.
  2. Conjugated mAbs that work by delivering a substance attached, or conjugated, to the antibody, directly to cells bearing cancer antigens.

The image below summarises the main actions of naked and conjugate mAbs.