How the immune system works
The immune system is a vital defense system in our bodies that protects against harmful pathogens like viruses, bacteria, and parasites as well as toxic substances. It can also recognize and ward off internal cell changes, such as cancer. The immune system contains a fascinating network of subsystems throughout the body that work in tandem — including lymph nodes, gut microbes, and several different organs. Our skin, sweat, and mucus also work to protect our bodies from pathogens by blocking or removing them. Here are the different components of the immune system and a brief breakdown of how they work together to keep us safe and healthy.
What does the immune system do?
The immune system’s main job is protection — it protects us from bacteria, parasites, and viruses. Some parts of the immune system, such as skin, sweat, and mucus, work as filters and barriers to keep harmful substances out, while other parts, like cells and antibodies, work to detect and attack these substances.
An immune response works by detecting antigens (any foreign body such as a virus, bacteria, toxin, or harmful fungus), recognizing these antigens as invaders, and forming antibodies to both attack them and save a record for the future. This copy remains in the body so that antigens can be detected and dealt with more quickly if it appears again.
Immune system components
Lymph nodes
Lymph nodes are found all over the body — like in your neck, throat, armpits, and groin — and act as filters to trap germs and activate antibodies when needed. If lymph nodes are swollen or painful, that’s a sign that the immune system is working to fight off infection.
Antibodies
Antibodies are specialized proteins that essentially hunt for foreign pathogens through detecting an antigen (short for “antibody generator”) and then mark the antigen so that it can be destroyed by other parts of the immune system. By keeping record, they ensure that the same antigen can be detected and destroyed more quickly if it enters the body in the future.
White blood cells
White blood cells are one of the primary components of our immune system and are even sometimes referred to as “immunity cells.” White blood cells are formed in our bone marrow and released when we’re sick to help our bodies fight off infections. White blood cells include lymphocytes like T cells and B cells, which can powerfully fight off infections and prevent them from coming back. Lymphocytes are why we get sick from illnesses like chicken pox only once.
T cells
T cells are a type of white blood cell that work by attacking antigens, including allergens and tumors. In infancy and childhood, T cells work to create “memory cells” that learn to detect and fight off foreign entities. In adulthood, T cells work to maintain this learned immunity and to fight off cancer cells and tumors.
Spleen and tonsils
These organs store immunity cells, support your lymph nodes, and sift out germs. The spleen filters out germs in the bloodstream and breaks down platelets (a small, colorless cell fragment with no nucleus) that can lead to blood clots. The tonsils contain white blood cells and protect and surround the lymph nodes in the throat.
Skin, sweat, and mucus
Our skin acts as a barrier to protect the more vulnerable parts of our body, and our sweat and mucus both work to trap pathogens and eliminate them.
Innate vs. adaptive immunity
The immune system contains two subsystems known as innate immunity and adaptive immunity, which work in different ways but are equally important. We are born with some level of innate immunity, whereas adaptive immunity is acquired throughout our lives. We also have some level of “passive immunity,” which is immunity that’s borrowed and only lasts a short period of time. For example, breast milk temporarily provides antibodies to newborn babies.
The innate immune system
The innate (or non-specific) immune system is meant to provide defense against a more general pool of harmful germs and toxic substances. Our skin, for example, acts as a barrier that protects against — and filters out — pathogens from entering our bodies. Mucus in our noses and throats can trap germs and push them out. And the digestive system recognizes toxic substances and expels them if needed.
The adaptive immune system
Adaptive (or acquired) immunity kicks in when a pathogen gets past the innate immune system. The adaptive immune system is constantly learning and adapting to fight off specific pathogens. It works through creating antibodies: specialized proteins that detect and attack specific antigens, while also creating records so they can be fought off more quickly in the future.
What is an immunization?
An immunization, or vaccine, is a product that’s designed to boost immunity to a specific disease, such as COVID-19. An immunization introduces specific antigens or dead pathogens to trigger the creation of antibodies. This allows the body to create an immune response without having to be exposed to the pathogen.
Natural ways to boost your immune system
To maintain a healthy immune system, it’s important to eat a diet rich in vitamins, minerals, and antioxidants that naturally support immunity. Some foods like ginger, turmeric, garlic, and mushrooms can be especially helpful. Sleep is also critically important for our immune system. But sometimes we need a little boost. Here are a few natural ways to support your immune system with supplements.
Echinacea and Zinc. Taking an echinacea and/or zinc supplement when you’re sick has shown to support your immune system and even shorten the length of time that you are sick.
Vitamin D. Vitamin D deficiency can increase your chances of getting sick. Try a Vitamin D supplement (like this one from Hum), especially in the winter when sunshine is in short supply.
Vitamin C. A Vitamin C supplement can help boost the production of white blood cells, so it might help your immune system when you’re sick.
Mushrooms. Some medicinal mushroom varieties have been shown to powerfully support the immune system and even fight off cancer cells and tumors. We suggest trying an immunity-specific mushroom supplement like this blend from Host Defense or this immune-boosting powder from Four Sigmatic.
Fermented foods and probiotics. Fermented foods like kimchi, kombucha, and yogurt contain probiotics that boost our gut bacteria, which can help our digestive system ward off infections and support our immune cells. It’s generally best to get probiotics from naturally fermented foods, but you might also consider a probiotic supplement.
Adaptogenic herbs. Herbs such as ashwagandha and Siberian ginseng work to combat the effects of stress in the body, which can lead to an improved immune system.
Katy Severson is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money.
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