Natural Killer Cells: What Immune System Role Do They Play?

Natural killer cells are one of the most important types of immune cells in our bodies. They help keep us healthy by killing cancerous or virus-infected cells when they enter the body, and have been shown to be a key player in fighting against some cancers. Read on to learn more about natural killer cells, including what they do, how they work, their role in the innate immune system, and ways that you can boost your own natural killer cell levels through diet and supplements.
What is the function of natural killer cells?
The main function of natural killer cells is to get rid of any “bad” (cancerous, infected) cells in our body. They do this by releasing enzymes which attack these cells, which the bad cells are unable to defend themselves against.
Natural killer cells kill these “bad” cell by releasing enzymes into them that attack and destroy them. This is different from other immune system defenses because natural killer cells can release their killing molecules without being a part of an antigen-antibody reaction.
Natural killer cells don’t attack cancerous or virus-infected cells like the other parts of our immune system do, but they are able to get rid of them much more quickly. They work in a way different from antibodies: natural killer cells can kill without first making an antigen-antibody reaction with their target cell. This makes them an especially powerful weapon against cancerous or virus-infected cells.
Natural killer cells are not specific to one type of cell–they kill what they recognize as “bad” cells without having to make a reaction with the target and defend themselves from that. This is different than other types of immune defenses, which require an antigen-antibody reaction with the target cell to kill it.
When were NK cells discovered?
Natural killer cells (NK) were first described by Polish scientist Paweł Olszewsk in 1964. At the time, they were thought to be a type of cytotoxic T cell because they kill tumor cells in an antigen-independent manner similar to other immune system responses. It was later discovered that NK cells are actually part of another type of immune response called innate immunity; this is why natural killer cells don’t work as well against certain cancers.
What is the innate immune system?
The innate immune system is the first line of defense against invaders to our bodies. It includes physical barriers like skin and coats, inflammatory cells such as natural killer cells that attack cancerous or infectious cells entering the body, and other defenses created by different parts of your immune system.
The “first layer” of protection in our immune systems are the physical barriers like skin and the coating on cells, called mucus. It also includes inflammatory cells such as natural killer cells that attack cancerous or infectious cells entering the body.
Other defenses include different parts of your immune system: white blood cells with specific antibodies to bind invaders, phagocytes which engulf these invaders and break them down into smaller pieces, and so on.

What is the role of NK cells in the innate immune system?
NK cells play a key role in the innate immune system by first being able to attack cancerous or infected cells entering our bodies. They are also one of the main regulators for inflammation, which is important because an overactive inflammatory response can lead to chronic diseases and autoimmune disorders.
How are natural killer cells produced?
Natural killer cells are produced in the bone marrow. They’re part of a type of white blood cell that starts off as stem cells, which then differentiate into natural killer cells.
Can I get tested to check the level of my NK cells?
There are blood tests that measure the level of natural killer cells in your body. If you want to test, visit an allergist or pulmonologist who can provide a simple cheek swab and send it off for testing. You’ll also be able to ask them any questions about NK cell levels and how they work. It’s important to note that there’s a difference between the number of NK cells in your body and their function. There are factors like obesity, alcohol consumption, smoking status, or chronic stress which can affect both numbers and function of natural killer cells.
Is there treatment for abnormal levels of natural killer cells?
If your natural killer cells levels are low, it can make you more likely to get sick and stay in a chronic state of disease. There is no known specific treatment for abnormal level of NKs but there are treatments for related illnesses, like cancer or chronic diseases.
Are natural killer cells good or bad?
Natural killer cells are essential to the immune system because they kill cancerous or infected cells without an antigen-antibody reaction. Antigen-antibody reactions are necessary to get the immune system going. Natural killer cells are just another type of white blood cell, but they have special abilities which make them important in many cases when an infection or cancerous growth is present.
NK cells in viral infections
Natural killer cells are important in viral infections. There’s a different type of natural killer cell for each virus that NKs target. For example cytotoxic T-lymphocytes can be used to kill HIV when it enters the body and erythrocyte progenitor cells attack Hepatitis C by destroying infected blood cells.
NK cells and cancer therapy
Natural killer cells are not typically used in cancer therapy. Instead, they play a key role in the innate immune system by first being able to attack and kill cancerous or infected cells entering our bodies through physical barriers like skin or lungs before these invaders can do any damage. Natural killer cell therapies have been shown to improve survival rates for certain types of cancer.
Can foods or health supplements increase natural killer cells?
There are certain foods that may increase natural killer cells. These include green tea, soy products, and turmeric. However there is not enough scientific evidence to know for sure if these actually do boost the immune system in this way.
There are also some supplements like vitamin D or curcumin which have been shown to improve NK cell activity in lab settings. Talk to your doctor about which ones might be best for you and make sure that they’re safe when combined with other medications or supplements.
Health and wellness are big in the world of network marketing

Among the biggest multi-level marketing businesses are companies that offer health and wellness products. One of these MLM companies is 4Life, which sells products that target the immune system. These include Immunotec, which is a line of nutritional supplements for people who want to increase their natural killer cells in order to fight illness or maintain health.
I Buy I Review recently explored how 4Life operates as an MLM company to determine if it’s legitimate or a scam. Read our review of 4Life here.

I buy and review courses so you don’t have to. Sometimes, I even find courses that are legitimate and worthwhile; and that’s how I accidentally came across one that led me to building a 6-figure business in a little under 5 years. Now, I still review courses because it’s my favorite hobby. 🙂 Learn more about me here.