Answer: cells that depress or regulate the responses of other T cells and B cells are known as regulatory T cells, often abbreviated as Tregs. The primary function of regulatory T cells is to maintain immune system balance and prevent excessive immune responses. Here's how they achieve this:Suppressing Excessive Immune Responses: Regulatory T cells play a crucial role in preventing the immune system from overreacting to harmless substances or its tissues (autoimmunity). They suppress the activation and proliferation of other T cells and B cells when their response is no longer needed to prevent unnecessary tissue damage.Tolerance Induction: Tregs help establish and maintain immune tolerance, which is the ability of the immune system to distinguish between self (the body's own tissues) and non-self (foreign invaders). They ensure that immune responses are focused on pathogens like bacteria and viruses, while sparing the body's own cells and tissues.Preventing Autoimmunity: Regulatory T cells are essential for preventing autoimmune diseases where the immune system mistakenly attacks the body's own tissues. By suppressing self-reactive T cells and B cells, they reduce the risk of autoimmune reactions and inflammation.Resolving Inflammation: In addition to preventing excessive immune responses, Tregs also play a role in dampening ongoing immune reactions. They help resolve inflammation after an infection or injury by suppressing immune cells involved in the inflammatory response, thus promoting tissue repair and healing.Maintaining Immune Homeostasis: Tregs contribute to immune system homeostasis, which is the delicate balance between immunity and tolerance. They ensure that the immune system remains in a state where it can effectively respond to pathogens without causing harm to the host.In summary, regulatory T cells are crucial for maintaining immune system balance and preventing inappropriate immune responses. They do so by suppressing the activation and proliferation of other T cells and B cells, thus helping to prevent autoimmune diseases and limit inflammation when it's no longer necessary. Their role is essential for overall immune system function and preventing immune-related disorders.