The One With Our T Cells

T cells. The name makes these little guys sound quite simple, but T cells are incredibly intelligent and important for fighting disease.

T cells make up a very important part of our immune system. More specifically, T cells are a certain type of white blood cell called lymphocytes. Other types of lymphocytes are B cells and natural killer cells (very cool name! I will cover these guys another time).

All of the blood cells in our body originate from our bone marrow, which essentially gives birth to and coordinates the sending of stem cells (baby, underdeveloped cells) to other areas of the body. These other areas of the body then help foster the development of these baby cells into specialised adult cells. For example, T cells are called T cells because they turn into adult cells in our thymus, which is right next to our heart.

There are many different types of T cells, but most can be categorised into killer T cells (how cool!) and helper T cells (below). Killer T cells are exactly like they sound, they can kills foreign objects (or pathogens in science speak) that enter our body.



The way they find these is also pretty cool, they swim around our bodies and scan our cells to see if there are any pathogens inside our cells, and if there is they destroy these cells. Helper T cells play important roles in our immune response, such as developing a memory that they’ve seen that pathogen before (by producing antibodies).

Most of our T cells are part of what is called our adaptive immune system, which is responsible for developing immunity to specific pathogens when they enter the body. Think of this as like a specialisation, one T cell becomes a specialist in its pathogen, knowing what it looks like, why it’s not part of our body, and what to do about it when the it encounters that pathogen and how to tell other T cells what to do.

One of the amazing things about T cells is how they can tell the difference between healthy and unhealthy (e.g. cancerous) cells within our body. T cells can read the signals on the outside surface of the cell and determine if the cell is healthy or not. If the T cell thinks the cell is unhealthy then it activates a pathway which ultimately leads to inflammation and destroys the unhealthy cell.

Unfortunately, sometimes T cells can become susceptible to a cancer called T-cell lymphoma. More broadly, lymphoma is a group of blood cancers that can develop from white blood cells, lymphocytes (mentioned earlier). T-cell lymphoma accounts for about 15% of all blood caners and there are a number of different subtypes of T-cell lymphomas, which usually cause people to present to their doctor with symptoms similar to the flu.

Fortunately, research is amazing, and there are some great researchers who have discovered a way to utilise T cells to fight cancer. There is a technique called chimeric antigen receptors (CAR) T cells (big words, but let’s focus on what it actually is!), which gives T cells the power to fight certain cancers. They achieve this by attaching an antibody (or signal) of a specific cancer to the T cells outer surface, so then the T cell will hopefully search for and find those cancerous cells and destroy them. In this process the T cell will also employ other T cells to help it out, hopefully overpowering the cancer.

This is just a mere speck of what T cells can do, so if you’d like to know more about T cells there is a great webpage called the Beginners Guide to T cells –, well worth a look.

Until next time.




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