As their name implies, the sole purpose of natural killer (NK) cells is to monitor, recognize and kill diseased and abnormal cells. NK cells are best known for their ability to destroy virally infected cells, as well as detect and control early signs of cancer. As part of the innate immune system, NK cells quickly and effectively respond to a wide variety of pathological challenges. This rapid response enables NK cells to track down and kill infected body cells, making them highly effective at preventing the spread of pathogens. Unlike other more common, but also highly specialized defender cells, NK cells comprise just 10 – 15 percent of all circulating white blood cells.
Interestingly, these lymphocytes are in constant contact with other cells as they peacefully patrol the body, effectively activating and rapidly multiplying once a target is identified. To determine when to attack a cell, NK cells utilize unique balancing signals from activating and inhibitory receptors on the NK cell surface. Activating receptors recognize molecules that are expressed on the surface of cancer cells and infected cells, and ‘switch on’ the NK cell attack mode. Most normal healthy cells express MCH I receptors, or autorecognition antigens that ensure their survival. These antigens generate a strong inhibitory signal, preventing NK cells from attacking and destroying healthy cells. Cancer cells and infected cells often have reduced MHC I capacity, leaving them susceptible to elimination by an advancing army of NK cells.
While the diverse functions of NK cells is not fully understood, their contribution as first-line defense responders and their essential role as inflammatory mediators is well established. Like tiny but mighty warriors on patrol, NK cells are recognized for their role in tumor immunosurveillance and anti-viral immune stimuli. Critical for defense against a wide variety of pathogens, NK cells possess a unique ability to identify infected cells and appear to form immunological memory. As ongoing efforts to identify strategies to optimize NK cell activity continue, the future looks promising for safe and effective treatment of chronic infections, as well as the potential to advance cell-based cancer immunotherapies.
As we age, our immune system response capability weakens, which increases our vulnerability to infections and raises the risk of developing age related conditions. Altered immune responses, gut microbiota imbalance and an unhealthy low-fiber, high-sugar diet may all contribute to the growing incidence of inflammatory autoimmune diseases, such as asthma, diabetes, and irritable bowel disease. The highly specialized intestinal microbiome is home to a complex society of diverse beneficial microorganisms, as well as potentially harmful pathogens, viruses and fungi and parasites. NK cells play a key role in the response to intestinal bacterial infections and appear to be involved in the regulation of gut mucosa homeostasis, or balance.
Favorable microorganisms act against pathogens, support immune activity and protect intestinal wall integrity. The intestinal microbiota is continually shaped by diet, aging, antibiotic use, medications, illness and environmental factors. Balance of the microbiota is essential for maintaining immune and overall healthy function, as dysbiosis, or an imbalance in gut microbiota composition, can result in an altered immune response. Imbalances may result from decreased immune cell production, micronutrient malnutrition, chronic stress, low fiber diet, unhealthy lifestyle choices and other factors. Following general wellness guidelines may support beneficial composition of the gut environment and ensure the proper function of the vast, intricate and interconnected immune system.
Per the World Health Organization (WHO), probiotic organisms confer a benefit to the host when administered in adequate amounts. Some studies have reported that NK cell activity, and subsequently innate immunity, may be enhanced by the addition of certain strains of dietary probiotics, specifically the most studied strains of Lactobacilli, Lactobacillus plantarum, L. paracasei, L. reuteri and L. rhamnosus. Research has shown Bifidobacterium longum may also benefit and stimulate NK cell activity, potentially priming the immune system against harmful pathogens.
Adopting healthy living strategies can naturally protect and help maintain immune, physical, mental and emotional wellness. To support good health and bolster immunity, eat a colorful and balanced, largely plant-based diet filled with nutrient, antioxidant and fiber rich vegetables and fruits, maintain a healthy weight, get adequate sleep, exercise regularly, hydrate sufficiently and minimize stress. As well, a daily multivitamin and mineral supplement can help meet micronutrient and cellular energy requirements and support overall healthy function.
Professional Supplement Center offers these and other high quality supplements in support of healthy immune function:
NK Killer Cell Support 60 – 90 Senior Essentials by Kirkman® Labs: This hypoallergenic formula blends antioxidant vitamins A, C and E with specialized antioxidant nutrients including CoQ10, lycopene, pycnogenol and resveratrol for powerful protection against free radical cellular damage and increased NK cell activity. Free of soy, wheat, casein, gluten, milk, eggs, yeast, gelatin, flavorings, colorings, peanuts and tree nuts.
Probiotic-10™ 25 Billion by Now® Foods: This probiotic formula offers a balanced spectrum of 10 clinically validated, acid resistant, live bacterial strains, including Lactobacillus plantarum, L. paracasei, L. rhamnosus and Bifidobacterium longum in support of intestinal integrity, healthy digestion and proper immune function. Free of dairy, soy, gluten, wheat, milk, eggs, fish, shellfish and tree nuts. Non-GMO, kosher, vegan formulation. Refrigerate to maintain potency.
Bifido Complex by Progressive™ Laboratories: Each capsule provides two billion acid and bile resistant strains of live microorganisms, including Bifidobacterium, Lactobacillus acidophilus, L. casei and L. rhamnosus, in support of overall digestive and immune function. Free of milk, soy, whey, corn, wheat, yeast and preservatives. Heat sensitive.
NK-3 Immune™ 500 mg by Source Naturals®: This product is formulated to support natural immune processes by stimulating chemical messenger production and supporting NK and other immune cell activity.
AHCC® Active Hexose Correlated Compound Powder by Planetary™ Herbals: This proprietary powdered formula blends several species of cultivated enzymatically modified mushroom mycelia in support of healthy immune function and increased NK activity. Also available in capsule form.
Natural Killer Cells. https://www.immunology.org/public-information/bitesized-immunology/cells/natural-killer-cells
The major histocompatibility complex and its functions. https://www.ncbi.nlm.nih.gov/books/NBK27156/
Harnessing the Healing Power of Self through Natural Killer Cells. https://www.ncbi.nlm.nih.gov/books/NBK27156/
Activation of Natural Killer Cells by Probiotics. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5467532/
Natural Killer Cells: Development, Maturation, and Clinical Utilization. https://www.frontiersin.org/articles/10.3389/fimmu.2018.01869/full
Role of human natural killer cells in health and disease. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC368214/
Strategies to Enhance NK Cell Function for the Treatment of Tumors and Infections. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6343663/