The immune system is an intricate, complex network of cells, organs, blood vessels, lymph nodes and more. The purpose of the immune system is to protect us from foreign invaders, or unwanted diseases that form from our own tissue, such as cancer.
The immune system is integral to fighting malignant mesothelioma, but it usually needs help to do so. Immunotherapy strengthens our immune system to better fight this rare cancer.
Immunotherapy is becoming more popular as a cancer treatment, and a therapy for mesothelioma. The U.S. Food and Drug Administration approved two immunotherapies, Opdivo and Yervoy, as an immunotherapy combination for mesothelioma. Patients can now receive this treatment at cancer centers or through their local oncologist.
It’s important for everyone – patients, family members and caregivers – to understand how immunotherapy for mesothelioma works. That first requires understanding some of the important parts of our immune system, most notably the cells that are key to the immune system’s response to cancer.
These five immune system cells are instrumental to fighting cancer, including mesothelioma.
T cells are white blood cells called lymphocytes. They are the primary soldiers of the immune system.
These cells have protein receptors on their surface. These receptors can link with protein receptors on cancer cells, which activates the T cells against the disease. Different types of T cells have different protein receptors.
Types of T cells
There are three types of T cells: cytotoxic, helper and regulatory.
Cytotoxic T cells, also called “killer” T cells, are on the front lines of fighting cancers such as mesothelioma. They’re one of the first responders to signs of infection, viruses and diseases such as cancer.
Helper T cells activate other immune cells to respond to infection. For example, helper T cells assist in preparing cytotoxic T cells to fight cancer.
Regulatory T cells are in charge of managing the immune system’s response to a disease. These cells prevent the immune system from going too far when trying to kill diseased tissue cells.
B cells are another type of white blood cell, or lymphocyte. They develop from stem cells in bone marrow.
B cells produce antibodies, which are crucial to the immune system’s response to cancer. Antibodies bind to cancer cells to kill them or stop them from invading healthy tissue. The release of antibodies and the binding of antibodies to cancer cells also alarms T cells and activates the immune system.
Natural Killer (NK) cells
Natural killer cells, or NK cells, are lymphocytes of the same family as T cells and B cells. NK cells are similar to T cells in their responsibilities. They respond to the presence of viruses and cancer, often joining T cells in the fight on the front lines.
The main difference between NK cells and T cells is how often they respond to cancer’s presence. NK cells are part of our body’s innate immune response. The non-profit organization Alliance for Cancer Gene Therapy explains what the innate immune response means.
“NK cells are part of the innate immune response, meaning they respond to any sign of something abnormal in the body. NK cells have a wider possible range of diseases they may confront. T cells are part of the adaptive immune response, which means they respond to specific irregularities based on the proteins.”
Dendritic cells are the link between the adaptive immune response and the innate immune response. They’re the antigen-presenting messenger cells of the immune system. Dendritic cells are responsible for downloading data about viruses and cancer cells and presenting this data to T cells, B cells and NK cells.
T cells struggle to use their protein receptors to bind directly to antigens on cancer cells. They need evidence of the antigens’ existence. This evidence comes from fragments of antigens, called peptides.
Dendritic cells present these peptides to the T cells. They’re able to infiltrate cancer cells and find hidden antigens that T cells cannot see.
Macrophages are called “cell eaters.” Their role is simple: locate, engulf, and destroy diseased tissue, such as mesothelioma cells.
Macrophages are a type of white blood cell called monocytes. They live in your tissue and look for infected cells to eliminate.
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