T cells

Definition

T cells are a type of white blood cell that plays a central role in the adaptive immune response. They originate in the bone marrow and mature in the thymus, where they learn to recognize specific antigens. T cells are essential for identifying and destroying infected or cancerous cells, and they also help orchestrate the overall immune response by communicating with other immune cells.

5 Must Know Facts For Your Next Test

1. T cells are divided into several subtypes, including helper T cells (CD4+), cytotoxic T cells (CD8+), and regulatory T cells, each serving distinct functions in the immune response.
2. Helper T cells activate other immune cells by releasing cytokines, while cytotoxic T cells directly kill infected or cancerous cells.
3. Regulatory T cells play a crucial role in maintaining immune tolerance and preventing autoimmune diseases by suppressing excessive immune responses.
4. T cell activation requires two signals: recognition of the antigen presented by antigen-presenting cells (APCs) and additional co-stimulatory signals.
5. The interaction between T cells and the microbiome can influence immune development and responses, impacting overall health and disease susceptibility.

Review Questions

• How do T cells differentiate between self and non-self antigens, and what role does this play in their function?
  • T cells differentiate between self and non-self antigens through a process called positive and negative selection during their maturation in the thymus. This ensures that only T cells capable of recognizing foreign antigens without reacting against the body's own tissues are allowed to mature. This capability is crucial for their function, as it prevents autoimmune responses while allowing them to effectively target pathogens.
• Discuss the importance of helper T cells in coordinating the immune response and how they interact with other immune cells.
  • Helper T cells are vital for coordinating the immune response because they release cytokines that stimulate other immune cells like B cells and cytotoxic T cells. By providing signals necessary for B cell activation and antibody production, as well as enhancing the activity of cytotoxic T cells, helper T cells ensure a well-organized attack against pathogens. Their ability to communicate with various components of the immune system makes them central players in adaptive immunity.
• Evaluate the impact of T cell dysregulation on health outcomes, particularly in relation to autoimmune diseases and cancer.
  • T cell dysregulation can have profound effects on health, leading to conditions such as autoimmune diseases where T cells mistakenly attack the body's own tissues. In contrast, inadequate T cell responses can contribute to cancer progression as tumors may evade immune detection. Understanding these dynamics highlights the importance of balanced T cell activity for maintaining health, where appropriate activation is critical for fighting infections and tumors while avoiding harmful autoimmune reactions.

Related terms

Antigen: A molecule or substance that is recognized by the immune system as foreign, triggering an immune response.

Cytokines: Signaling molecules released by immune cells that facilitate communication and coordination among various components of the immune system.

B cells: Another type of white blood cell that works alongside T cells to produce antibodies and adaptively respond to pathogens.