Regulatory T Cells: Study with Video Lessons, Practice Problems & Examples

Regulatory T cells, or Tregs, are a specialized subset of helper T cells that play a crucial role in inhibiting immune responses. Unlike cytotoxic T cells that promote immune activity, Tregs prevent the immune system from attacking healthy cells, thus helping to avoid autoimmune reactions. They achieve this through mechanisms of peripheral tolerance, ensuring the immune system does not overreact to harmless substances. Ongoing research continues to uncover the detailed functions of Tregs, highlighting their importance in maintaining immune homeostasis.

Regulatory T Cells

In this video, we're going to briefly talk about regulatory T cells. And so these regulatory T cells are commonly abbreviated as Tregs. And these regulatory T cells or Tregs are unlike the other T cells that we've talked about so far. Because the other T cells, including the cytotoxic T cells and the helper T cells, are all about stimulating and generating an immune response. However, the regulatory T cells or the T regs are all about inhibiting and preventing an immune response. And so these regulatory T cells or Tregs are really a subset of the helper T cells that are going to once again inhibit self-reacting T cells ultimately involved with preventing autoimmune reactions, preventing our own immune system from attacking our own healthy cells. And so these Tregs play an important role. They help to make sure that our immune system does not target our own cells. And so once again, these T regs are unlike the other types of T cells because the other types of T cells are promoting and initiating immune responses. However, the T regs are all about stopping the immune system response. And it stops the immune system response from overreacting and responding to harmless substances. And that's a good thing, we do not want our immune system to overreact and to respond to harmless substances. So these T regs have an important role. However, the detailed role of the T regs is still being studied and still being revealed today. It's undergoing research as we speak. And so more and more information will become available about these regulatory T cells. Now, these regulatory T cells, again, what they can do is they can inhibit the activity of other T cells via peripheral tolerance mechanisms during development. Again, helping to prevent immune system responses from overreacting and targeting self cells. And so if we take a look at this cartoon that we have down below of these regulatory T cells we can get a little bit of a better understanding of what they are involved with. And so notice over here on the left-hand side what we have are some immune system cells, here represented as a SWAT team. We have a CD8 cell over here or cytotoxic T cell, and perhaps some neutrophils and things like that. And notice that these T cells over here are self-reacting because they're saying we need to destroy that cell over there. But notice that this cell over here is a normal cell, that is displaying normal cytoplasmic proteins on its MHCs. And so because this is a normal cell, we do not want our immune system targeting this normal healthy cell. And so these, right here in the middle, this represents our regulatory T cell or in other words, our T reg cell. And the T reg cell is all about stopping and inhibiting the immune system response from overreacting and targeting self cells. And so notice here our regulatory T cell is saying "stop, this cell is perfectly healthy, do not attack it." And so these regulatory T cells help to inhibit the immune response, whereas the other types of T cells that we've talked about are all about promoting and generating immune responses. And so this year concludes our brief lesson on regulatory T cells, and we'll be able to get some practice applying these concepts as we move forward. So I'll see you all in our next video.

Which of the following is NOT a function of regulatory T cells?

• A. Regulatory T cells contain receptors that remove cytokines required for the growth and proliferation of effector cells.
• B. Regulatory T cells induce apoptosis of effector cells via perforin and granzyme.
• C. Regulatory T cells secret cytokines that reduce the signaling activity of effector T cells.
• D. Regulatory T cells interact with MHC class I APCs and inhibit their maturation.

What does it mean when $T_R$$_e$$_g$ cells control lymphocyte functions via peripheral tolerance?

• A. $T_R$$_e$$_g$ cells show T and B lymphocytes in the peripheral lymphoid organs which antigens to attack.
• B. $T_R$$_e$$_g$ cells inhibit T and B lymphocytes that have exited the primary lymphoid organs from attacking self-antigens.
• C. $T_R$$_e$$_g$ cells control the production of T and B lymphocytes and ensure only cells with immune tolerance proliferate.
• D. $T_R$$_e$$_g$ cells inhibit T and B lymphocytes that are maturing within the primary lymphoid organs.

Here’s what students ask on this topic:

What are regulatory T cells (Tregs) and what role do they play in the immune system?

Regulatory T cells, commonly known as Tregs, are a specialized subset of helper T cells that play a crucial role in maintaining immune system balance. Unlike cytotoxic T cells and other helper T cells that stimulate immune responses, Tregs inhibit immune activity. Their primary function is to prevent the immune system from attacking the body's own healthy cells, thereby avoiding autoimmune reactions. Tregs achieve this through mechanisms of peripheral tolerance, ensuring that the immune system does not overreact to harmless substances. This inhibition is essential for preventing conditions where the immune system mistakenly targets normal, healthy cells.

How do regulatory T cells (Tregs) prevent autoimmune reactions?

Regulatory T cells (Tregs) prevent autoimmune reactions by inhibiting the activity of self-reactive T cells. They achieve this through mechanisms of peripheral tolerance, which occur outside the thymus during immune system development. Tregs can suppress the activation and proliferation of other T cells that might mistakenly target the body's own cells. By doing so, they ensure that the immune system does not overreact to normal, healthy cells or harmless substances, thereby preventing autoimmune diseases. This regulatory function is crucial for maintaining immune homeostasis and preventing the immune system from causing self-damage.

What mechanisms do regulatory T cells (Tregs) use to inhibit immune responses?

Regulatory T cells (Tregs) use several mechanisms to inhibit immune responses. One primary method is through the secretion of inhibitory cytokines such as IL-10 and TGF-β, which suppress the activity of other immune cells. Tregs can also directly interact with other T cells to inhibit their activation and proliferation. Additionally, Tregs can modulate the function of antigen-presenting cells (APCs) to reduce their ability to stimulate immune responses. These combined actions help Tregs maintain immune tolerance and prevent the immune system from attacking the body's own healthy cells.

Why is ongoing research important for understanding the detailed functions of regulatory T cells (Tregs)?

Ongoing research is crucial for understanding the detailed functions of regulatory T cells (Tregs) because their role in the immune system is complex and not yet fully understood. As we uncover more about how Tregs function, we can better understand their mechanisms of action and their impact on immune homeostasis. This knowledge can lead to new therapeutic strategies for treating autoimmune diseases, allergies, and even cancer. By studying Tregs in greater detail, researchers can develop targeted treatments that enhance or inhibit their activity, providing more effective and personalized medical interventions.

How do regulatory T cells (Tregs) differ from other types of T cells?

Regulatory T cells (Tregs) differ from other types of T cells, such as cytotoxic T cells and helper T cells, in their primary function. While cytotoxic T cells and helper T cells are involved in stimulating and generating immune responses to fight infections and diseases, Tregs are focused on inhibiting immune responses. Tregs prevent the immune system from attacking the body's own healthy cells and from overreacting to harmless substances. This inhibitory role is essential for maintaining immune tolerance and preventing autoimmune reactions, making Tregs a unique and critical component of the immune system.