What is the primary function of Treg cells in the immune system?

Treg cells, or regulatory T cells, play a crucial role in maintaining immune homeostasis by regulating immune system activity. Their primary function is to suppress excessive immune responses and prevent autoimmune diseases, thereby ensuring that the immune system is responsive enough to defend against pathogens while also being restrained to prevent damage to the body's own tissues. Treg cells achieve this through various mechanisms, including the secretion of anti-inflammatory cytokines and direct interaction with other immune cells to inhibit their activity.

Understanding the primary role of Treg cells highlights the importance of balance in the immune system. Without this regulatory function, the immune system may become overactive, leading to conditions such as allergies or autoimmune disorders. This perspective aligns with the concept that the immune response's effectiveness relies not only on activating immune cells like B lymphocytes or other leukocytes but also on having an adequate system in place to control and modulate these responses. Therefore, the correct answer is centered around the core function of Treg cells as regulators of the immune response.