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. 2013 Oct 29;2:e01599.
doi: 10.7554/eLife.01599.

Immune to Defeat

Free PMC article

Immune to Defeat

Michael L Reese. Elife. .
Free PMC article


A dramatic example of the 'arms race' between hosts and pathogens has been observed in the response of mice to the parasite that causes toxoplasmosis.

Keywords: IRG proteins; Mouse; Other; Toxoplasma gondii; coevolution; virulence.

Conflict of interest statement

Competing interests:The author declares that no competing interests exist.


Figure 1.
Figure 1.. Hosts vs parasites.
Toxoplasma parasites can kill laboratory mice (left) because they secrete effector molecules (ROP5 & ROP18) that prevent the effector IRG proteins (dark green) in the immune system of the mice from doing their job, which is to prevent the Toxoplasma parasites (grey) replicating themselves inside a vacuole. Lilue et al. show that in mice derived from wild mice (right), a particular isoform of an IRG protein (Irgb2-b1) binds to the ROP5 molecules, which means that the effector IRG proteins can assemble on the surface of the vacuole. This allows wild-derived mice to control an otherwise lethal infection in a way that, seemingly paradoxically, enables the survival of both the host and the parasite (which survives inside cysts in the brain and muscle tissue of the host).

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