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The immune system is made up of a complex network of organs, cells and proteins that fight infection (microbes). keeps a record of every microbe it has ever defeated, in types of white blood cells (B-lymphocytes and T-lymphocytes) known as memory cells. This means it can recognise and destroy the microbe quickly if it enters the body again, before it can multiply and make you feel sick.

, have to be fought many times because so many different viruses or strains of the same type of virus can cause these illnesses. Catching a cold or flu from one virus does not give you immunity against the others.

The main parts of the immune system are: thymus

White blood cells are the key players in your immune system. They are made in your bone marrow and are part of the lymphatic system. White blood cells move through blood and tissue throughout your body, looking for foreign invaders (microbes) such as , parasites and fungi.

When they find them, they launch an immune attack. White blood cells include lymphocytes (such as B-cells, T-cells and natural killer cells), and many other types of immune cells. Antibodies help the body to fight microbes or the toxins (poisons) they produce.

They do this by recognising substances called antigens on the surface of the microbe, or in the chemicals they produce, which mark the microbe or toxin as being foreign.

The antibodies then mark these antigens for destruction

There are many cells, proteins and chemicals involved in this attack. The complement system is made up of proteins whose actions complement the work done by antibodies. is a network of delicate tubes throughout the body.

The main roles of the lymphatic system are to: absorb some of the fats in our diet from the intestine. The lymphatic system is made up of: lymph vessels – tubes that carry lymph, the colourless fluid that bathes your body’s tissues and contains infection-fighting white blood cells white blood cells (lymphocytes). is a blood-filtering organ that removes microbes and destroys old or damaged red blood cells.

It also makes disease-fighting components of the immune system (including antibodies and lymphocytes). is the spongy tissue found inside your bones. It produces the red blood cells our bodies need to carry oxygen, the white blood cells we use to fight infection, and the platelets we need to help our blood clot.

The thymus filters and monitors your blood content

It produces the white blood cells called T-lymphocytes. As well as the immune system, the body has several other ways to defend itself against microbes, including: – mucous in the lungs (phlegm) traps foreign particles, and small hairs (cilia) wave the mucous upwards so it can be coughed out – body fluids like skin oil, saliva and tears contain anti-bacterial enzymes that help reduce the risk of infection.

The constant flushing of the urinary tract and the bowel also helps.

This is actually an immune system response

A rise in temperature can kill some microbes. Fever also triggers the body’s repair process. It is common for people to have an over- or underactive immune system. can take many forms, including: – where the immune system makes an overly strong response to allergens.

Allergic diseases are very common

They include: – where the immune system mounts a response against normal components of the body.

Autoimmune diseases range from common to rare

  • systemic vasculitis. Underactivity of the immune system
  • also called immunodeficiency
  • such as common variable immunodeficiency (CVID)
  • x-linked severe combined immunodeficiency (SCID)
  • complement deficiencies An underactive immune system does not function correctly
  • makes people vulnerable to infections

It can be life threatening in severe cases

Immunoglobulins (commonly known as antibodies) are used to treat people who are unable to make enough of their own, or whose antibodies do not work properly. This treatment is known as Until recently, immunoglobulin therapy in United States mostly involved delivery of immunoglobulins through a drip into the vein – known as intravenous immunoglobulin (IVIg) therapy.

Now, can be delivered into the fatty tissue under the skin, which may offer benefits for some patients. This is known as subcutaneous infusion or SCIg therapy.

Subcutaneous immunoglobulin is similar to intravenous immunoglobulin

It is made from plasma – the liquid part of blood containing important proteins like antibodies.

to read more about this type of treatment

Many health services are now offering SCIg therapy to eligible patients with specific immune conditions.

If you are interested, please discuss your particular requirements with your works by copying the body’s natural immune response. A vaccine (a small amount of a specially treated virus, bacterium or toxin) is injected into the body.

The body then makes antibodies to it

If a vaccinated person is exposed to the actual virus, bacterium or toxin, they won’t get sick because their body will recognise it and know how to attack it successfully. The immunisations you may need are decided by your health, age, lifestyle and occupation. Together, these factors are referred to as HALO, which is defined as: – some health conditions or factors may make you more vulnerable to vaccine-preventable diseases.

For example, premature birth, asthma, diabetes, and HIV will mean you may benefit from additional or more frequent immunisations. – at different ages you need protection from different vaccine-preventable diseases. sets out recommended immunisations for babies, children, older people and other people at risk, such as Aboriginal and Torres Strait Islanders.

Most recommended vaccines are available at no cost to these groups. – lifestyle choices can have an impact on your immunisation needs. , and playing contact sport that may expose you directly to someone else’s blood, will mean you may benefit from additional or more frequent immunisations.

For example, if you work in aged care, childcare, healthcare, emergency services or sewerage repair and maintenance, discuss your immunisation needs with your doctor.

Some employers help with the cost of relevant vaccinations for their employees

Immune system The immune system and microbial infection The immune system Some infections, like the flu and the common cold Parts of the immune system white blood cells antibodies complement system lymphatic system spleen bone marrow White blood cells bacteria, viruses Antibodies Complement system Lymphatic system The lymphatic system manage the fluid levels in the body react to bacteria deal with cancer cells deal with cell products that otherwise would result in disease or disorders lymph nodes (also called lymph glands) – which trap microbes Spleen The spleen Bone marrow Bone marrow Thymus The body’s other defences against microbes skin – a waterproof barrier that secretes oil with bacteria-killing properties lungs digestive tract – the mucous lining contains antibodies, and the acid in the stomach can kill most microbes other defences Fever is an immune system response A rise in body temperature, or fever Common disorders of the immune system Overactivity of the immune system allergic diseases allergies to foods , medications or stinging insects anaphylaxis (life-threatening allergy) hay fever (allergic rhinitis) sinus disease asthma hives (urticaria) dermatitis eczema autoimmune diseases multiple sclerosis autoimmune thyroid disease type 1 diabetes systemic lupus erythematosus rheumatoid arthritis be inherited – examples of these conditions include primary immunodeficiency diseases arise as a result of medical treatment – this can occur due to medications such as corticosteroids or chemotherapy be caused by another disease – such as HIV/AIDS or certain types of cancer People who have had an organ transplant Immunoglobulin therapy immunoglobulin replacement therapy (IRT) subcutaneous immunoglobulin (SCIg) therapy Download the Subcutaneous Immunoglobulin - information sheet for patients clinical immunology/allergy specialist Immunisation Immunisation Vaccinations are available against many diseases, including measles and tetanus Health heart , lung, spleen or kidney conditions, Down syndrome Age United States’s National Immunisation Program Lifestyle Travelling overseas to certain places , planning a family, sexual activity , smoking Occupation View the HALO infographic Where to get help Your GP (doctor) A specialist (ask your GP for a referral – the specialist you need may be a dermatologist , rheumatologist or clinical immunology/allergy specialist ) American Society of Clinical Immunology and Allergy (ASCIA) – Locate a specialist Allergy and Anaphylaxis United States Immune Deficiencies Foundation of United States (IDFA) 1800 100 198.

Key Points

  • main parts of the immune system are: thymus
  • White blood cells are the key players in your immune system
  • main roles of the lymphatic system are to: absorb some of the fats in our diet from the intestine
  • common for people to have an over- or underactive immune system
  • Allergic diseases are very common