Tracking down allergies
Decoding T cell regulation in allergies
What works differently in the immune system of allergic persons? Which immune cells can be held responsible for immune system overreaction? Scientists from Berlin, together with the e:Med consortia e:Kid around Professor Nina Babel, have now shed light on these questions and have decoded the role of the different T cells in allergies.
Highlight from the e:Med Newsletter:
The air around us contains an enormous number of the smallest particles of both, harmful agents and harmless substances. Our immune system faces the challenge of distinguishing between the two in order to react against dangerous agents and at the same time tolerate harmless substances. It is generally accepted that specific immunosuppressive cells (Treg) inhibit the immune response to harmless substances by blocking allergenic cells (Th2). However, in some humans, harmless pollen may cause a pathologic immune response due to excessive T cell activity, which leads on to the development of allergies. It was presumed for a long time that allergies were caused by a defect of the immunosuppressive Treg cells, not only because of methodical limitations, the evidence is missing. With the help of a new technology in this study large numbers of antigen- (allergen-) specific T cells were isolated from the blood and analyzed by e:Med scientists using specifically established methods. In this context, researchers have found that there is no difference in regulatory T cells between healthy individuals and persons suffering from an allergy, neither quantitatively nor qualitatively. They have further shown that specific easily-soluble substances generally trigger only a reduced activation of these regulatory cells. It is precisely these substances that may lead to allergies, through the lower control of the Tregs, the allergenic Th2 cells are freer to react. Thus, in allergic patients, the regulatory T cells are fully functional; however, Th2 cells are overreacting causing allergy symptoms. It is still unclear, why Th2 cells are using this loophole in patients while they behave “normal” in healthy persons. The finding, that the degree of activity in Tregs is dependent on the antigen, can help to optimize allergy therapy by specifically activating these cells which again suppresses immune active Th2 cells.
Original publication:
Bacher, P., Heinrich, F., Stervbo, U., Nienen, M., Vahldieck, M., Iwert, C., Vogt, K., Kollet, J., Babel, N., Sawitzki, B., Schwarz, C., Bereswill, S., Heimesaat, M.M., Heine, G., Gadermaier, G., Asam, C., Assenmacher, M., Kniemeyer, O., Brakhage, A.A., Ferreira, F., Wallner, M., Worm, M., Scheffold, A., 2016. Regulatory T Cell Specificity Directs Tolerance versus Allergy against Aeroantigens in Humans. Cell 167, 1067–1078.e16. doi.org/10.1016/j.cell.2016.09.050
Contact:
Prof. Nina Babel, e:Kid Konsortium
Charité - Universitätsmedizin Berlin
nina.babel@charite.de