Question

We talked a lot about Treg cells and their importance not only in the immune system, but in overall health and disease. Explain each of the following about Treg cells, using sketches where they aid your explanations.

A. How do Treg cells help shut off an immune response that has developed against a pathogen once the pathogen is no longer present?

B. How does the presence of Treg cells influence "allergies" that develop in response to food we eat? ... In response to dust mites we inhale?

Answer 1

A) T Regulatory cells are also known as suppressor T cells because they help the body's immune system stay in check by regulating their activity. They not only shut down immune reactions once the invading pathogen is eliminated from the body, but also help in preventing autoimmune reactions.

The suppressing activity of T reg cells is not very well defined, but a lot of hypotheses have been effectively proven over the years. T reg cells produce inhibitory cytokines such as Transforming Growth Factor Beta, Interleukin 35, and Interleukin 10. These cells can also induce other cell types to produce inhibitory interleukins which serve to suppress immune activity. Apart from these, they also produce Granzyme B, which induces apoptosis of T effector cells. They can also directly interact with dendritic cells and suppress their activity.

B) Recent studies have shown that T regulatory cells play an important role in promoting tolerance to allergens and preventing allergic diseases. There are many mechanisms through which this is achieved. They directly act on mast cells, blocking their degranulation, and controlling hypersensitivity reactions. This is a particularly important mechanism in food allergies that are largely mediated by mast cells and IgE.