A protein in mice known as RGS13 suppresses allergic reactions including the severe, life-threatening allergic reaction known as anaphylaxis, according to scientists at the NIAID.
RGS13, a regulator of G-protein signaling (RGS), is also found in humans and is expressed in only a limited number of cells including the immune system's mast cells that are central to allergic reactions. It is known to inhibit cellular responses induced by G-protein-coupled receptors.
The investigators made a group of mice deficient in the RGS13 gene. The NIAID team compared localized anaphylactic reactions between the deficient mice and normal mice. They injected an allergen, IgE antibody, and a blue dye under the skin of the mice. The results showed that RGS13-deficient mice had a larger and more intense blue reaction than normal mice, indicating that their blood vessels leaked more.
To test for systemic anaphylaxis, they injected the IgE antibody and a blue dye directly into the veins of the mice. The organs of RGS13-deficient mice showed an anaphylactic response that was twice as large as that of the normal mice.
The study also found that RGS13 inhibits the activity of PI3 kinase, an enzyme involved in many biological processes including those involved in cancer and diabetes.
The research is described in a report online in Nature Immunology.