What Does Your Immune System Actually Do?

Our immune system does a remarkable job of keeping us healthy, by fighting off diseases that could potentially harm us. Some immune systems are stronger than others and for certain individuals the immune system fails, either allowing surrounding bacteria and viruses to enter the body, or not responding to them when they do, resulting in sickness.

We tend to hear a lot about our immune system, but what does it actually do?

The immune system is made up of a network of cells, tissues and organs and is our body’s defence mechanism,  fighting off disease-causing microbes (pathogens). Even though a lot of research has been conducted on the immune system, there’s still a lot of ground to be covered in order to understand how it can be manipulated in order to target faulty cells such as cancer cells, while continuing to protect the healthy ones.

What forms our immune system?

Our immune system is formed of two main parts; the innate system and immunity. The innate system is the defence system that we are born with – nonspecific defence mechanisms that start working within hours of an antigen (usually a toxin or foreign substance) entering the body. The second part, referring to our immunity, develops as we grow older. It protects us against certain pathogens (bacterium, viruses or other microorganisms causing disease) and locks them in its memory. This is beneficial for us, as our body recognises a pathogen the second time it appears in our body and therefore responds quicker in order to fight off the infection.

Where can we find our immune system?

Our immunity is not located in just one place. The innate system is spread around the body, starting with the first line of defence, which is the skin. The skin is waterproof and acts as a barrier, preventing the entry of pathogens into more vulnerable areas. We produce sticky mucus through the mucous membranes in our cavities (such as our nose and mouth) that keep bacteria from entering further. Our body also produces other internal fluids that help fight off pathogens. For example, the gastric juice produced by our stomach, which is very high in acid – killing off the bacteria we ingest. Saliva is another liquid secreted into the mouth by glands, which washes pathogens off our teeth, lowering the level of oral bacteria. These defences are not the only ones, if pathogens do manage to enter, they are faced with a second-line of defence.

The second part of our immune system is the one that provides us with immunity. This involves activation of our lymphocytes (a type of white blood cell), which are found in our blood and other specialised lymph tissue. This is another very important part of our immune system as it doesn’t only fight off pathogens, it also makes antibodies which combine chemically to foreign substances in order to destroy them. Vaccinations are a way of tricking the body into ‘memorising’ a particular infection that it hasn’t experienced before, providing us with future protection.

For example, when we injure ourselves, the area we damage usually swells up. This is because inflammation is part of our body’s immune response, triggering a release of chemicals which make it easier for specialised leukocytes to go to the injured area. Leukocytes are colourless cells which are found in your blood and body fluids and are involved in fighting off foreign substances, which is the reason that they are normally called white blood cells. Leukocytes are made inside our bone marrow and stored in our blood and lymphatic tissues. Some leukocytes have a short lifespan (1-3 days), which is why our bone marrow is constantly making new ones.

What happens when the immune system turns against you?

The body’s immune system has the ability of attacking and destroying healthy tissue in your body by mistake, this is referred to as an autoimmune disorder. There are over 80 different kinds of autoimmune disorders including:

• Lupus
• Diabetes
• Underactive/Overactive Thyroid
• Multiple Sclerosis
• Rheumatoid Arthritis

Why does this happen?

Generally, your white blood cells are there to protect you against harmful substances that pose a health risk, such as bacteria, viruses, cancer cells and foreign blood and tissues. All of these substances contain antigens and these prompt a reaction from your immune system, which in turn produces antibodies to fight off the antigens. A body that is suffering from an autoimmune disorder will have an immune system that does not distinguish between its healthy tissues and the antigens that the harmful substances contain. This triggers the immune system to destroy the healthy ‘normal’ tissues in the body as well.

What makes the immune system ‘go rogue’? 

The specific cause of all autoimmune disorders is not yet known, some theories say that some drugs or microorganisms may influence and confuse the immune system. Other theories of autoimmune disease triggers are:

• Bacteria/virus
• Chemical irritants
• Environmental irritants

What are the symptoms of an autoimmune disorder?

There are over 80 different AI diseases, each with its own specific set of symptoms. However, there are some symptoms which are common amongst those who suffer from an AI including fevers, fatigue and generally feeling ill. Symptoms can also increase and decrease in severity depending on flare-ups and remissions.

The most common organs to be affected by these diseases are:

• Joints
• Muscles
• Skin
• Red blood cells
• Blood vessels
• Connective tissue
• Endocrine glands

If you feel like your immune system may be struggling and are experiencing symptoms similar to the ones listed above, then it would be best to contact your doctor for a general check up to be on the safe side.