Novel process for worm-mediated immunosuppression in the skin
On the 20th of December the journal Mucosal Immunology published an article with results contributed from several MTC researchers. Susanne Nylén lead the study.
Congratulations Susanne to your publication in Mucosal Immunology!
What are the most important results of your study?
We show in this work how T- cells colonize the skin after infection with a relatively benign intestinal worm infection and that this has long-term effects on immune cell composition and local immune responses in the skin, revealing a novel process for worm-mediated immunosuppression in the skin.
Why are these results important?
The reduced prevalence of helminth infections in the past 50-100 years has been linked to an increase in autoimmune and inflammatory disorders in Western societies. Intestinal worm infections have been suggested to have beneficial effects on inflammatory skin disorders with reduced atopy and allergic reactions in the skin. This study shows that intestinal worms upregulate skin homing receptors on circulating T cells and cause seeding of worms specific T-helper 2 cells in the skin. This results in dampened immune responses towards stimulations with other antigens or infections given in the skin, explaining previously observed immune-regulations in skin of worm-infected mice. Further our results propose a novel explanation to the geographically mutually exclusive high prevalence of immune mediated inflammatory skin disorders and the stronger responsiveness to the intradermally administered tuberculosis vaccine BCG, observed around the world.
How can this new knowledge contribute to improving human health?
The functional advantage of the observed recruitment of CD4+ T cells into skin is not clear. Several parasitic worm species infect through the skin and skin-homing TH2 cells could provide direct protection against repeated exposure to larval forms of the same skin-infecting nematode or cross-protection against other worms. If we can harness the signals induced by the worms that allows T cells with immune regulatory properties to colonize the skin (and other tissues) we could in the future potentially use these to alleviate inflammatory diseases.
How did you conduct the study?
This was an experimental study carried out in mice that were infected with the nematode Heligmosomoides polygyrus.
What is the next step in your research?
We would like to follow up this study by more in detail addressing how worms induce skin homing molecules on T cells and if we can mimic the effect of worms and create a less inflammatory prone tissue T cells without having to infect the animal.