Some cells of the immune system activate or deactivate depending on the presence of the steroid they produce, researchers from the UK report.
Their discovery could help to better understand the course of cancer, autoimmune diseases and parasitic infections.
The research was conducted by teams of scientists from two British institutes: the European Bioinformatics Institute (EMBL-EBI) and the Wellcome Trust Sanger Institute in Cambridge. Their results were published in the Cell Reports journal.
We were very surprised that immune cells can make steroids, says lead author of the study, Dr. Bidesh Mahata. “Through cell culture experiments, we saw that these compounds play an important role in regulating the proliferation of T cells. At first, we didn’t know where they came from. It is now clear that the T cells produced them themselves.
As Mahata explains, anyone who has ever used steroids, for example in the fight against eczema, knows that these substances effectively suppress the immune response and reduce inflammation. Under normal circumstances, it is similar – when the body feels that the immune cells have finished working, it produces steroids to eventually shut them down. But which specific cells are responsible for this production so far has not been known.
Dr. Mahata’s team looked at the behavior of Th2 helper cells during a parasitic infection. It has been noticed that at some point these cells start to produce a steroid called pregnenolone.
We were very surprised by this fact. But because we had access to data from previous experiments on single cell lines, we were able to perform in-depth statistical analysis on a very large and authoritative dataset, says Dr. Sarah Teichmann, co-author of the study. Thanks to this, we identified the genes involved in the production of pregnenolone and concluded that it was the Th2 lymphocytes themselves that were involved in immunosuppression.
Scientists explain that balancing the immune system is an integral part of any immune response.
Then we further confirmed our assumptions experimentally, showing that pregnenolone inhibits both the proliferation of Th lymphocytes and the conversion of B lymphocytes to plasma cells, Mahata adds. – We believe that the phenomenon of Th2 cell differentiation into steroid-producing cells is part of a larger mechanism that allows the immune system to return to a state of equilibrium each time. (PAP)