In brief
Your body's defence network. It defends you against infection while protecting your own cells, and it keeps a record of every germ it has defeated.
- Fever is an immune system response.
- In the gut, the mucous lining contains antibodies, and stomach acid can kill most microbes.
- Long-lasting stress can make you more vulnerable to infection and illness, according to healthdirect.
How it works
White blood cells are the key players. Blood cells are made in the bone marrow, the thymus produces white blood cells called T-lymphocytes, lymph nodes trap microbes, and the spleen filters the blood to remove microbes and old or damaged red blood cells. Antibodies help the body fight microbes and the toxins they produce.
The immune system keeps a record of every microbe it has ever defeated, and immunisation works by copying this natural immune response. Problems arise when it makes an overly strong response to harmless allergens, causing allergies, or mounts a response against the body's own tissues, causing autoimmune conditions.
Going deeper
The immune system has two subsystems. Innate immunity is a general, non-specific defence against germs, using cells such as phagocytes, which eat germs, and natural killer cells. Adaptive immunity is specific. It is constantly learning and adapting, makes antibodies to fight particular germs, and usually stores information about a germ so it can recognise it straight away next time.
Connections
11 connections on the map. Select a topic to read its page.
Immune system is linked with
The gut's mucous lining contains antibodies, and stomach acid can kill most microbes.
Source: Better Health Channel (Victorian Government), Immune system explained
Hay fever is an allergic reaction that happens when the immune system responds to an allergen.
Psoriasis is an immune system condition. It happens when the immune system makes skin cells grow too fast.
Immune system includes
Lymph nodes trap microbes, and the spleen filters the blood to remove microbes.
Sources: Better Health Channel (Victorian Government), Immune system explained; Better Health Channel (Victorian Government), Lymphatic system
The immune system defends against infection while protecting the body's own cells.
Sources: Better Health Channel (Victorian Government), Immune system explained; InformedHealth.org (IQWiG), NCBI Bookshelf, In brief: How does the immune system work?
Immune system is supported by
- Vitamin D Supported
Your immune system needs vitamin D to fight off invading bacteria and viruses.
Source: NIH Office of Dietary Supplements, Vitamin D fact sheet for consumers
Vitamin C helps the immune system work properly to protect the body from disease.
Source: NIH Office of Dietary Supplements, Vitamin C fact sheet for consumers
Immune system can be worsened by
- Chronic stress (allostatic load) Supported
Long-lasting stress can make you more vulnerable to infection and illness, according to healthdirect.
Source: healthdirect Australia, Stress
Immune system is affected by
- Trouble sleeping Supported
Getting enough sleep helps keep your immune system strong, according to healthdirect.
Source: healthdirect Australia, Sleep
Immune system makes
Inflammation is the immune system's response to an irritant, such as a germ or a foreign object.
Source: InformedHealth.org (IQWiG), NCBI Bookshelf, In brief: What is an inflammation?
Immune system needs
Zinc helps your immune system fight off invading bacteria and viruses.
Source: NIH Office of Dietary Supplements, Zinc fact sheet for consumers
Lab tests
Medicines and supplements
General education only. Never start, stop or change a medicine without your prescriber.
Sources
Each connection above names its own source. See every source AskBioMap uses.
Summarised from the Better Health Channel and healthdirect. Sources read on 13 October 2026. General education only, not medical advice. Spotted a mistake? Please tell us through the HuBu-Intel contact page.