Final answer:
Regulatory T (Treg) cells play a crucial role in maintaining immune system balance by suppressing the activity of other immune cells through the release of inhibitory cytokines, thus ensuring the body's defenses do not incorrectly target its own tissues.
Step-by-step explanation:
The regulatory T (Treg) cells are responsible for preventing a hyperactive immune system from causing harm by differentiating between self and non-self entities. These specialized cells maintain immune system balance by releasing inhibitory cytokines that suppress other immune cells, thereby ensuring the body does not mount an immune response against itself. Immune tolerance is an essential mechanism within the immune system that allows for the suppression of immune responses towards harmless or self-antigens. Regulatory T cells play a key role in this process, thus preventing autoimmunity.
These Treg cells are critical for concluding the immune response after an infection has been eliminated and for avoiding unnecessary activation by non-threatening substances or the body's own cells. This is especially significant in areas where foreign substances are frequently encountered, such as the mucosa of the upper digestive system. The helper T cells release cytokines that direct the immune response, by activating other immune cells such as macrophages, cytotoxic T cells, and B cells.