T-cells: Terminators of The Immune System

TYPES, THERAPY, TIPS

WHAT ARE T-CELLS?

A T-cell is one of two particular types of lymphocytes (a kind of white blood cell) that determines the specificity of an immune response to antigens in the body. An antigen is any foreign substance that activates an immune response. It may be a product or a part of a virus, fungi, bacteria, parasite, or harmful chemical. The T-cell is a vital part of adaptive immunity, a subsystem of your immune system that must be developed over a lifetime. It can learn and adapt to fight disease-causing microorganisms that evolve. The primary members of this subsystem include B-cells and T-cells. We’ll have more on B-cells in a future article. Let’s focus on T-cells in this article.

WHAT ARE THE DIFFERENT TYPES OF T-CELLS?

T-cells, also called T lymphocytes, are produced in the bone marrow and specialise (mature) in a glandular organ in the chest called the thymus. T-cells rapidly increase in numbers in the thymus and differentiate into killer (or cytotoxic), regulatory, helper, or memory T-cells. These are the different types of T-cells. The thymus can be compared to a university that offers four kinds of courses to a T-cell. After choosing a course, the T-cell completes it and graduates from the university. It’s now one of the four types of T-cells. It’s ready to go out into the world and get a job. The T-cells are sent to different organs and tissues or travel in the lymphatic system or blood. By the way, the T in T-cell stands for thymus.

Once an antigen arrives and enters the body, helper T-cells make cytokines (chemical messengers) which stimulate the specialisation of B-cells to produce antibodies. Antibodies are proteins made to protect your body. Next, regulatory T-cells control the immune reaction to the antigen. They try to make sure that the response is just right, not too much and not too little. Another function of cytokines is to activate killer T-cells which attach to and eliminate infected cells and even cancer cells. Some T-cells aren’t called into the present reaction and serve as memory T-cells. They remember the information regarding the antigen and are called to respond when the same antigen is encountered. The resulting response is quicker and more effective.

WHAT ARE THE FUNCTIONS OF T-CELLS IN CANCER? WHAT IS IMMUNOTHERAPY?

T-cells play a massive role in the never-ending fight against cancer.

1. Helper T-cells deal with cancer indirectly. They plan and put together the mechanisms on how to fight cancer cells.
2. Killer T-cells eliminate cancer directly. They actively search for cancer cells and kill them.

Cancer immunotherapy, also called immuno-oncology, is a cancer treatment that utilises your body’s immune system to control, eliminate, and prevent cancer. It has the potential to treat all types of cancers. As mentioned before, T-cells have a significant role in immunotherapy (helper and killer T-cells). There are different types of cancer immunotherapy. They can be conveniently categorised into five types:

1. Targeted antibodies are customised proteins produced in the laboratory to target antigens on cancer cells. Their main goal is to disrupt cancer cells' unrestrained growth and activity. Some of these targeted antibodies have drugs attached to them delivered straight to the tumour.
2. Oncolytic virus immunotherapy utilises viruses that are usually altered to infect tumour cells. This causes tumour cells to self-destruct. The fun begins when these processes attract the attention of T-cells to kill the primary tumour and potentially other tumour cells throughout the body. T-VEC or talimogene laherparepvec is approved for treating melanoma (a type of skin cancer) that’s inoperable. T-VEC is a modified version of HSV or herpes simplex virus, the virus that’s responsible for cold sores.
3. Adoptive cell therapy takes a cancer patient’s immune cells and modifies them. These cells are then reinfused into the patient. The immune cells, including T-cells, search and destroy cancer cells. An example of a therapy in this group is CAR T-cell therapy. Under this therapy, T-cells are altered and equipped with specialised targeting receptors for cancers called CARs (chimeric antigen receptors) that enhance anti-cancer activity. Adoptive cell therapy shows promise in treating certain types of blood cancers (leukaemia and lymphoma).
4. Immunomodulators orchestrate the activity of other immune system cells to unlock new or amplify existing immune responses to tumour cells. Cytokines (interleukins and interferons) are examples of immunomodulators that can be made in the laboratory to enhance the immune response. They’re used in the treatment of melanoma and kidney cancer.
5. Cancer vaccines evoke an immune response against tumour-specific or tumour-associated antigens. These vaccines influence the immune system to target tumour cells with antigens. Cancer vaccines can be divided into treatment vaccines and prevention vaccines. An example of a treatment vaccine is sipuleucel-T (Provenge®) which treats inoperable and advanced prostate cancer resistant to hormone therapy. Gardasil® is an example of a prevention vaccine. It protects against HPV or human papillomavirus, which causes cervical cancer.

HOW CAN WE HELP T-CELLS IN OUR BODIES?

If you want to help your T-cells, you have to support your entire immune system. Below are some practical tips and the latest research studies on how you can support your immune system with emphasis on your T-cells:

1. Exercise helps T-cells act against cancer progression. A 2020 research study in mice demonstrated that during exercise, the muscles released molecules that enhanced the activity of killer T-cells making them more effective in fighting cancer cells. This resulted in reduced tumour growth. The same results were seen when they transferred the T-cells and other immune cells into mice that didn’t exercise (improved T-cell activities). The exact mechanism as to how this happens remains unclear. But there’s one thing clear. Exercise improves T-cell function in the immune system, not just against cancer but also against infections. Just keep your exercise levels between light to moderate. Overexertion and strenuous activities do the exact opposite to your immune system. You can also alternate between cardio (cardiovascular training) and strength training. Both stimulate your immune system to produce more cells that fight infection and cancer.


2. Improve your immune system by avoiding pro-inflammatory foods. Inflammation takes a tremendous toll on your body, especially your immune system. It’s made up of active cells that work 24/7, even if you’re not sick. T-cells continue to function as long as there’s inflammation or infection.



Frequent consumption of pro-inflammatory foods puts your body in a chronic inflammatory state. Chronic inflammation puts you at risk for heart disease, diabetes, Alzheimer’s Disease, and arthritis. Stay away from the following pro-inflammatory foods:



1. Lard, margarine, shortening
2. Red meat and processed meat
3. Soda and sweetened drinks
4. Fried foods and processed carbohydrates



Increase your intake of the following well-known anti-inflammatory foods:



1. Fruits like cherries and oranges
2. Fish – mackerel, tuna, salmon, and sardines
3. Nuts – walnuts and almonds
4. Green leafy vegetables like kale, collards, and spinach
5. Tomatoes and spinach may increase lymphocyte (where T-cells come from) resistance to oxidative damage enabling them to live longer.
6. Olive oil
7. Garlic. Scientists believe that certain garlic compounds can stimulate the increase in T-cell numbers and their responsiveness when needed.



All these anti-inflammatory foods are low in calories and contain compounds that limit the effects of pro-inflammatory cytokines (chemical messengers).



3. Don't hesitate to use supplements. First, talk to your doctor before taking any supplements. You can opt to take a multivitamin and mineral complex type of supplement, or you can take several supplements depending on your needs and nutritional status. Just make sure you don’t skip on the following nutrients for the benefit of your T-cells:



NUTRIENT	SIGNIFICANCE TO T-CELLS
Amino acids, especially glutamine, branched chain amino acids, and arginine	Serve as energy source and raw material for protein synthesis in the course of activating and differentiation of T-cells.
Vitamin D	Stimulate T-cells to be more alert and responsive.
Vitamin A, C, and E	Act as antioxidants that reduce reactive oxygen species after T-cell activation.
Selenium	Activate T-cells to be more efficient especially during tumour growth among cancer patients.
Zinc	Essential for T-cell development and regeneration of the thymus.
Echinacea	Demonstrated to directly activate Regulatory T-cells in some research studies.

Note: You don’t have to be sick to take nutritional supplements. Make it a habit to keep taking them even if you feel well to avoid nutrient deficiencies.



4. Do you have allergies? Allergic reactions keep your body in a pro-inflammatory state, leading to chronic inflammation. Food allergies (e.g., nuts) and hay fever keep your immune cells, especially the T-cells working overtime. Learn how to handle your allergies and the best ways to avoid allergens.


5. Avoid toxins in your surroundings. Toxins are everywhere. You can find them in cleaning products, plastic containers, personal care products, pesticides, and food. Don’t smoke or quit smoking. Consume moderate amounts of alcohol.


6. Too much stress can depress your immune system and decrease T-cell function and numbers. High and prolonged levels of stress hormones and inflammation in your body negatively affect T-cell function. Minimise stress by doing meditation, going to the sauna, massage therapy, getting enough sleep, etc.

Your T-cells are an integral part of a team, your immune system. Their ability to fight infection and cancer cells places them at the cutting edge of research and medicine. To take good care of your T-cells, you must think about your entire immune system, including the cells, tissues, and organs in it. T-cells may be the terminators of the immune system, but they also need some tender loving.