In a recent poll of my Twitter followers, I asked (on a whim while writing an article for work) what their favorite lymphocyte was.
Cytotoxic T cells (Tc cells) were the clear winner (disclaimer – Twitter only allows four choices. There are of course many other lymphocytes to choose from). Tc cells are also known as Killer T cells, and rightfully so, due to the fact that they recognize certain patterns on the surfaces of cells either infected with an infectious microorganism or that are growing abnormally (tumor cells). Even their name suggests their nature: cyto – (cell) toxic (deadly). After recognizing the dangerous cells, Tc cells then act on their own to kill them, releasing enzymes like perforin, granzymes, and granulysin.
Perforin enzymes literally poke holes in the membrane of the suspicious cell, allowing granulysin and granzymes to enter. Granulysin attacks the surface of any viral particles, bacterial cells, or parasitic organisms that may have invaded. In some cases, granzymes enter the invader and cause it to self-destruct.
Or, in the words of University of South Florida medical school student Scott Nelson, “they can kill all by themselves.”
Let’s take a minute and think about the underdogs of the poll results, the unsung heroes of immune protection: regulatory T cells. Although a meager nine percent of the responses to my poll indicated these lymphocytes were immune cells of choice, they certainly deserve a shout out.
While T helper cells are off stimulating cytokine production, activating B cells and running the block during a pathogenic invasion, the regulatory T cells stay primed for preventing any autoimmune activity that may occur by accident. The body’s immune system is prone to erring just like any other machine, and regulatory T cells exist to prevent and reverse any potentially deleterious actions of helper T cells if they were to accidentally target the body’s own cells, mistaking them as foreign antigens.
So while lymphocytes like T helper cells and Tc cells are out fighting pathogenic crime and protecting the body from infection (by all means a noble venture), regulatory T cells stay at home in case of dangerous mutiny or friendly fire.
Now you know a little bit more about what T cells do for our body, especially important to consider since we’re in the middle of flu season. On that note, I never even mentioned B cells, the other piece of the immunological puzzle, being the lymphocytes that are responsible for antibody production. Until next time…