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New anti-parasite protective mechanism

Nature Immunology

June 30, 2008

Scientists have discovered how the immune system fights Toxoplasma gondii, a parasite that causes the disease toxoplasmosis in humans, according to a paper online this week in Nature Immunology.

Immune cells called CD8+ T lymphocytes are required to fight T. gondii, which can cause severe disease in humans with weak immune systems. These cells recognize parasite-derived protein fragments displayed on the surface of infected cells. Nilabh Shastri and colleagues show that a fragment of the T. gondii protein called GRA6 is a target of CD8+ T lymphocytes and induces a protective immune response in mice.

They also showed that the host cell protein ERAAP, which acts as a scissor to ‘clip’ proteins into fragments, is required for the production of this protective GRA6 fragment. This is the first time ERAAP has been shown to have a specific and protective role in the immune response to pathogens.

doi: 10.1038/ni.1629 | Original article

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