Select a Topic
- What is the Immune System?
- How Does the Immune System Work?
- What Can Go Wrong with the Immune System?
- Help for the Immune System
- More Information on Immune System
What is the Immune System?
The immune system is an amazingly intricate and complex system that keeps us healthy and protects us against all sorts of viruses, bacteria, microbes, parasites, and toxins.
To help us understand the power of our immune system, it is useful to take a look at what happens when anything dies, including the human body. Within hours after death, the body is invaded and taken over by a multitude of different bacteria, parasites, etc., and it does not take long for the body to be broken down and dismantled until all that remains is the skeleton. When we are alive this doesn’t happen - which just goes to show us how powerful and important our immune system is.
Like with many things, we often don’t think about our immune system until something goes wrong with it. Therefore, taking extra care in strengthening the immune system can help prevent many problems related to a weak system, such as many common immune disorders.
How does the Immune System Work?
The immune system has many different components both inside and outside the body. Starting from the outside, there are many different barriers that form part of the immune system.
The immune system is an immensely complicated and intricate system, and like all systems in the body, it needs to be in top condition to perform optimally. If it is compromised in any way, it will allow the germs to win the battle and disease will develop. We are surrounded by germs of all descriptions at all times without getting sick. When our immune system is compromised and cannot effectively fight off the infection, we become ill.
External Lines of Defense
The Skin – The skin is obviously a physical barrier to many germs and toxins, as it contains special immune cells called Langerhans cells that act as warning bells to alert the immune system to any foreign agents. Langerhans cells also regulate the immune response to these agents, evident in the skin’s reaction to stinging nettles or a cat scratch. The skin also secretes antibacterial substances which hinder the growth of bugs on our skin.
The Mucus Membrane Linings - The eyes, nose, and mouth are all possible ports of entry for invading germs, but our tears, nasal secretions, and saliva all contain enzymes or cells of the immune system to keep the invaders at bay. The mucus membrane linings of the respiratory, gastrointestinal, and genitourinary tracts also provide one of the first lines of defense against invasion by microbes or parasites.
Internal Lines of Defense
If the germs make it past this first line of defense, they encounter a number of immune components inside the body including:
- The lymphatic or lymph system
- The thymus gland (in your chest)
- The spleen
- Bone marrow
- White blood cells or leukocytes
The Lymphatic or Lymph System
The swollen glands that we all check for in the neck are in fact lymph nodes that are part of the lymphatic system. The lymph system is similar to the circulatory system, in that it is an interconnected series of vessels carrying lymphatic fluid, except that lymphatic fluid is not pumped around the body (like the heart pumps blood), but rather it moves passively. Fluid oozes in and out of the lymphatic system with normal body and muscle movement. Lymph contains plasma (the watery part of the blood) and helps to carry nutrients, oxygen, and waste products from the blood cells through the capillary walls. Germs generally find their way into this fluid and are then carried to the lymph nodes, which act as filters. The lymph nodes filter the fluid, and if there are any germs, the immune cells in the node rise to the occasion to fight them off. If the lymph nodes swell up during this process, this acts as a sure indication of infection. The filtered lymphatic fluid is then returned to the blood stream where the cycle starts again.
The Thymus Gland
The thymus gland is situated in the chest in front of the heart but behind the breast bone, and is responsible for producing T-cells, one of the important germ-fighting cells of the immune system. The thymus gland is very important for newborn babies (who need it to survive), but as we get older it becomes less important, as other parts of our immune system manage to compensate.
All the cells of the immune system are originally derived from the bone marrow. Our bone marrow produces blood cells – both red cells, which carry oxygen, as well as white blood cells, which are part of the immune system. There are many different types of white blood cells including T-cells, B-cells, natural killer cells, lymphocytes, etc. and they all work together to destroy the foreign cells or germs. The B-cells produce antibodies, or proteins that are specific to the germ (or antigen, which is anything foreign to the body) encountered. Specific B-cells are tuned into specific germs, and when that germ is present, the corresponding B-cell multiplies rapidly and produces the antibodies to destroy that germ. The antibodies then bind to the germ and prevent it from entering our cells. If this is not enough, the antibodies will cover the germ and signal the complement system for assistance.
The spleen is also an important filtration organ, as it searches for and filters out foreign cells as well as old red blood cells that need replacing. In addition, the spleen plays an important role in activating appropriate immune responses by presenting the antigen to the appropriate T or B cells, which in turn can then produce large amounts of anti-bodies.
White blood cells or leukocytes
Immune cells are white blood cells, otherwise known as leukocytes, which are produced in large quantities in the bone marrow. There is a great variety of leukocytes, each with a specific function and role to play in the working of the immune system. Some of these blood cells seek out and destroy foreign organisms, some dispose of infected or mutated body cells, while others release proteins called antibodies that alert other cells to destroy invading organisms.
Antibodies are Y-shaped proteins found in the blood and are made by B-cells. Essentially these proteins are used by the immune system to identify and block the effects of antigens. Thus when an antigen (or foreign cell) is identified, an antibody attaches itself - like a key fits into a lock – and neutralizes the effect of the antigen.
The Complement system
The complement system is a series of different proteins that work with (or compliment) the antibodies. These proteins flow freely in the blood and can therefore rapidly reach the site of an invasion where they can react directly with antigens (molecules that the body recognizes as foreign and potentially dangerous). When triggered, these complement proteins can trigger inflammation, attract eater cells such as macrophages to the area, cover intruders so that eater cells are more likely to destroy them, and directly kill intruders by causing the cells to burst. This in turn signals other ‘clean up’ cells, called phagocytes to come and remove the burst cell. Other substances such as hormones, tumor necrosis factor, and interferons also play an integral part in the functioning of the immune system.
What Can Go Wrong with the Immune System?
- Autoimmune disorders
- Immunodeficiency disorders
- Allergic disorders
- Cancers of the immune system
Autoimmune disorders occur when the immune system mistakenly attacks the body’s own tissues and organ cells. So instead of white blood cells attacking harmful antigens and pathogens, the immune system starts attacking healthy cells for reasons that are not yet clearly understood. There are more than 80 different types of autoimmune disorders which include:
- Addison’s Disease
- Rheumatoid arthritis
- Multiple Sclerosis (MS)
- Graves' disease
This category of immune disorders occurs when a part of the immune system is not present or not working as it should. Some people are born with an immune deficiency (called primary immunodeficiency), in which case they tend to be more inclined to catching colds, getting infections and allergies than most others. Other immunodeficiencies are acquired either through disease, injury, or certain medications. Some of the most common causes of immunodeficiency include:
- HIV (human immunodeficiency virus) and AIDS (acquired immunodeficiency syndrome)
- After-effects of chemotherapy and radiation therapy
- After-effects of other immunosuppressant medication, such as corticosteroids and drugs used to prevent transplant rejection
- Sickle cell anemia
- Certain infections such as measles
- Severe burn trauma
Many individuals suffer from allergies caused by a hypersensitivity reaction of the immune system to certain allergens in the environment. Some common allergens which trigger this reaction are dust, pollen, pet hair, bee stings, and certain foods. When these antigens enter the body, the immune system tends to overreact and antibodies quickly cause the release of histamine, which results in an allergic reaction. These reactions differ in severity and may include itchiness, hives, rhinitis, and in more serious allergies, swelling of mucous membranes such as in the nose and throat, leading to potential difficulties and anaphylaxis. Common allergic disorders include:
- Contact dermatitis
- Food, environmental, and insect bite allergies
Cancers of the Immune System
When cells of the immune system are over-produced and the normal body mechanisms of keeping them in check fail, they become out of control and the result is cancer. For example, when the body over-produces white blood cells, the result is leukemia. Other cancers associated with the immune system are:
- Hodgkin's disease
- Multiple myeloma
While not all of these immune disorders are preventable, some are, and necessary precautions should be taken to ensure that you give your immune system all the help it needs to remain strong and resilient against illness. Eating a healthy diet, getting enough exercise, practicing good hygiene and safe sex can go a long way to assisting and maintaining your immune system.
Help for the Immune System
Antibiotics treat bacterial infections when the immune system alone couldn’t mount an adequate response against immune disorders. Therefore a strong and healthy immune system should negate the need for any antibiotics in the majority of situations, therefore it is so critical to always consider strengthening the immune system by taking preventative measures, to help avoid unnecessary medication.
What are Antibiotics?
Antibiotics are specific chemicals aimed at killing off the targeted bacteria (they are not effective against viruses and should not be taken for a viral infection). In theory antibiotics are supposed to do this without damaging the cells of our body, but antibiotics do come with side effects and consequences. The paradox is that antibiotics were developed to help the immune system, but in reality they actually impair it. This paradoxical effect was first noted in 1950, but couldn’t be confirmed, and it was only in 1972 at the Baylor School of Medicine in Houston that it was documented that some antibiotics actually prevented white blood cells from attacking and killing bacteria. This included some of the well-known antibiotics used today such as tetracyclines, erythromycin, and chloramphenicol.
It is fairly common practice nowadays to take probiotics when on an antibiotic to replace the ‘good’ bacteria in our digestive tract in order to reduce the gastric side effects of the antibiotics. However, there are also bacteria in the stomach that produce specific proteins that stimulate our immune systems. When these bacteria are killed off too, a temporary halt is put on our immune system and this increases susceptibility to additional infections.
The Drawbacks of Antibiotics
Excessive use of antibiotics sets up a vicious cycle:
The more you take antibiotics, the more you depress your immune system. The more depressed your immune system is, the more likely you are to get another infection. If you get another infection, you will get another antibiotic, and so the vicious cycle continues.
In addition, because of improper prescribing and usage by patients, the incidence of antibiotic-resistant bacteria is increasing. This can lead to serious illnesses as well, as people taking more than one antibiotic for one infection or taking a much stronger, and more dangerous, antibiotic.
Similarly, there are also many over-the-counter preparations available that do as much harm as good, and for which the long-term side effects are not always known. In medical trials, it is usually only the short-term efficacy and side effects that are tested and measured.
It is also important to remember that many of the symptoms that we seek to treat are actually the body’s way of dealing with the infection and are proof that the immune system is working and doing its job. For example, a runny nose with a cold is the body’s way of trying to rid itself of germs, and trying to stop this process also stops the body from expelling the pathogen.
More Information on Immune System
Self-Care Prevention Measures
Here are some of the lifestyle factors that you can employ to keep your immune system in peak condition and able to ward off recurrent infections.
- Make sure that you get enough sleep – this means both an adequate quality of sleep as well as an adequate length of sleep. Sleep is one of the most important factors in maintaining a strong and healthy immune system
- Ensure that you have a wholesome, nutritious diet rich in fresh fruits, and vegetables (preferably organically grown), whole-grains, legumes and natural oils.
- Exercise and keeping active is not only good for your body and your mind, but also helps to optimize immune functioning. In addition, regular moderate exercise will help to relax you and will also encourage healthy sleep. Not to mention, the more we move, the more our lymph is circulated - thus, the better this system can function.
- Maintain a healthy weight. Being too thin or overweight can equally depress the immune system.
- Stress is also bad for the immune system. While small amounts of stress can be beneficial, prolonged stress depresses the immune system. If you are experiencing anything like this it is important to treat it. Anxiety and depression can also compromise the immune system – a healthy mind leads to a healthy body.
- Laugh – the chemicals produced when we are happy have receptor sites on cells all over our body so happy minds can make happy, healthy cells
- Don’t smoke and avoid secondhand cigarette and tobacco smoke. The chemicals contained, even in secondhand smoke, all depress the immune system and have a negative impact on its functioning.
- Reduce exposure to germs. Practice good hygiene habits such as washing your hands before meals and after going to the toilet. Stay away from people who are sick and, where possible, keep your children in smaller day care centers or crèches.
- Avoid the excessive use of antiseptic and antibacterial soaps, sprays, and other detergents. While these may kill bacteria and other organisms in the short term, they also contribute towards the development of resistant strains of bacteria which at times can reach epidemic proportions. Use natural ingredients such as Tea Tree oil and certain aromatherapy essential oils. Do not keep children ‘too clean’. A certain amount of ‘healthy dirt’ is good for the immune system!
- We are surrounded by toxic chemicals and pollutants wherever we go, at home and in the environment. Where possible use safe non-toxic chemicals at home, in your toiletries and in your gardens.
- Avoid excessive sun exposure, as this can depress the immune system – this is why cold sores are so common after spending time in the sun. Sunlight is necessary to produce Vitamin D so don’t avoid it entirely, just be sensible about the time of day and length of time you spend in the sun, and wear sun block.
- Avoid the vicious antibiotic cycle. While antibiotics may be necessary in some cases, they are generally over-prescribed and used as a first option instead of a last resort. Try exploring natural health options, as there are many herbs with a long history of use that are well-known to strengthen different parts of the immune system.