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This image may not be used in educational posters ^BCell-mediated immune response,^b computer artwork. This type of immune response is most often used against intracellular pathogens, such as viruses. The viruses (gold) are phagocytosed (engulfed) by macrophage cells (green), a type of white blood cell. Fragments of viral protein (antigen) are displayed on the macrophage's surface. The antigen is recognised by a helper T lymphocyte (purple, centre and right), which secretes chemicals to activate other immune cells, including cytotoxic T lymphocytes (purple, left and bottom). The cytotoxic cells release chemicals that cause the macrophages to disintegrate and die, killing the viruses inside as well.

How to tell if your immune system is weak or strong

31 January 2023

New blood tests can reveal whether your immune system is fighting fit by looking at the balance of different immune cells, but there may be a simpler way of gauging your immune health
Evolution explains why social distancing due to covid-19 is so hard

Evolution explains why social distancing due to covid-19 is so hard

11 November 2020

Hugs, handshakes and air kisses serve the same crucial purposes as animal greetings like sniffing, eye poking and buttock grabbing

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