How does the immune system work? When your immune system is working properly, it: Tells the difference between cells that are yours and those that don’t belong in your body. Activates and …

Mar 11, 2025 · The immune system defends the body from invaders such as viruses, bacteria, and foreign bodies. Find out how it works, what can go wrong, and how to boost immune health.

The immune system works to keep germs and other foreign substances out of the body and destroy any that get in. It's made up of a complicated network of cells and organs.

Apr 13, 2025 · The immune system is a vast, interconnected network of organs, cells, and molecules that protects your body from harmful substances, pathogens (like bacteria, viruses, …

Nov 29, 2025 · The immune system is a group of defense responses found in humans and other advanced vertebrates that helps repel disease-causing entities. Immunity from disease is …

Feb 3, 2025 · Your immune system defends your body against harmful invaders like viruses and bacteria, using white blood cells, antibodies, and other defenses to maintain health.

All immune cells come from precursors in the bone marrow and develop into mature cells through a series of changes that can occur in different parts of the body.

After exposure to a pathogen, our bodies generate a primary immune response. Subsequent exposures benefit from secondary (or memory) immune responses. Each is discussed here.

Nov 19, 2025 · Short on time? Here’s what to know: The immune system relies on different types of white blood cells. Phagocytes, for example, engulf and digest pathogens. B-cells (or B …

Understand how your immune system works with clear, science-backed insights. We empower you to make informed decisions and feel confident about your health.