Th2-biased immune responses are believed to be important in the immune responses against helminth infections. If, however, Th2-biased immune responses are inappropriately directed against innocuous antigens, such as allergens, tissue damage and inflammation may ensue. These inappropriate Th2 responses underlie asthma, eczema, hay fever and some food allergies.
Th2 cytokines induce the isotype switching of B-cells to the synthesis of IgE. They also promote the growth, differentiation and release of mast cells and eosinophils from the bone marrow. Eosinophils are directed towards sites of helminth infection and allergy by chemokines, such as eotaxin, which are released by Th-cells. Th2 cytokines also activate eosinophils. In a situation analogous to Th1-biased responses, Th2-biased Th-cells induce a package of biological responses that are characteristic of allergy and helminth infection, namely, high levels of circulating IgE, mastocytosis and tissue eosinophilia.
Was this article helpful?
If you suffer with asthma, you will no doubt be familiar with the uncomfortable sensations as your bronchial tubes begin to narrow and your muscles around them start to tighten. A sticky mucus known as phlegm begins to produce and increase within your bronchial tubes and you begin to wheeze, cough and struggle to breathe.