What is the immune system?
The immune system is a network of cells and glands throughout the whole body that responds to injuries and pathogens, and works to remove any stimuli that are foreign to the system. Essentially, there are two branches of our immune system: innate and adaptive.
The innate immune system is comprised of things like our skin and digestive tract, and its purpose is to defend our system against anything that isn’t part of it: things we are innately immune to like dirt in food or the bacteria on the outside of our skin. Any substance or organism that wasn’t produced by our body is blocked by the innate immune system. Skin physically keeping dirt out, mucous membranes absorbing toxins we inhale, and our stomach acid dissolving the cell membranes of bacteria, are all examples of our first line of defense.
The adaptive immune system is much more specialized. Where the innate immune system targets everything foreign, the adaptive immune system targets only specific pathogens that it has learned to recognize. The focus of this article is on the role of endocannabinoids in the innate immune system.
White blood cells make up the bulk of our immune system, and they keep our blood clean. They also have many CB2 receptors, which arouse the cell and initiate a specific immune response depending on which endo- or phyto- cannabinoid activated them. Although there are many different kinds of immune cells, there are two main classes: neutrophils and lymphocytes.
Neutrophils make up around ⅔ of white blood cells. Like their name, they bind neutrally without preference to anything that is foreign to the body. They are mostly found in the blood stream, which is our second line of defense. Anything foreign is generally referred to as a pathogen, and includes bacteria, fungus, and viruses.
Lymphocytes comprise around ⅓ of white blood cells, but they actually spend most of their time in the fluid between cells, or the lymph system; this is our third line of defense. From this position, they catch most pathogens before they make it from the blood to the cells. Lymphocytes are also neutrally binding, at first. Later, we’ll talk about their key role in the adaptive immune system.
The innate immune system
Lymphocytes and neutrophils generally comprise the portion of our innate immune system that doesn’t involve acid or snot. Instead, they are each covered with around 10,000 protein chains called antibodies. Antibodies bind to small chunks of a pathogen called antigens. The antibody on the immune cell sticks to the antigen on the pathogen. The cell then absorbs the pathogen and salvages it for parts. This is a fundamental characteristic of all of our immune cells, but it is the only [important] function of neutrophils.
When certain lymphocytes called B-cells bind to an antigen, they become activated. What this means is that they make copies of themselves because they’re the B-cell that binds with that specific pathogen, and pathogens don’t usually travel alone. All of the copies that it makes of itself attach to as many of the pathogens as possible, helping your body to wipe out a potential infection. After so many B-cells are replicated, certain endocannabinoids get released that tell other immune cells to attack the B-cells with that antigen, and this brings balance once the infection is gone. However, around 1% of the B-cells remain around as memory cells. More on that in the next article.
Key point: When immune cells are being created, their genes are modified to ensure that they don’t create antibodies that would destroy your own cells. This process of weeding out the self-binding immune cells is initiated by cannabinoid receptors inside stem cells that go on to become immune cells. Following activation of CB2 receptors, these stem cells produce an enzyme that shuffles a specific few genes around, so that the antibodies it produces are attracted only to proteins that your own genome can’t code for. When this mechanism fails, autoimmune deficiencies like AIDS result.