T lymphocytes

Definition

T lymphocytes, or T cells, are a type of white blood cell that play a crucial role in the adaptive immune response. They originate from hematopoietic stem cells in the bone marrow but mature in the thymus, which is where they gain their name. T cells are essential for identifying and eliminating infected or cancerous cells and coordinating the immune response by interacting with other immune cells.

5 Must Know Facts For Your Next Test

1. T lymphocytes are divided into different subtypes, including helper T cells (CD4+) and cytotoxic T cells (CD8+), each with specific functions in the immune response.
2. Helper T cells enhance the immune response by activating B cells and other immune cells through the secretion of cytokines.
3. Cytotoxic T cells directly kill infected or cancerous cells by recognizing specific antigens presented on their surfaces.
4. T cell activation requires two signals: recognition of an antigen presented by major histocompatibility complex (MHC) molecules and co-stimulatory signals from other immune cells.
5. Memory T cells are formed after an infection has been cleared, allowing for a quicker and stronger response to subsequent exposures to the same antigen.

Review Questions

• How do T lymphocytes contribute to the adaptive immune response?
  • T lymphocytes contribute to the adaptive immune response by identifying and eliminating infected or abnormal cells. There are various types of T cells, including helper T cells that activate other immune components and cytotoxic T cells that directly kill infected or cancerous cells. This interaction is critical for effectively targeting pathogens and mounting a coordinated immune response.
• Discuss the role of cytokines in the functioning of T lymphocytes during an immune response.
  • Cytokines play a vital role in the functioning of T lymphocytes by facilitating communication between different immune cells. When activated, helper T cells release cytokines that stimulate B cell activation and proliferation as well as recruit other immune cells to the site of infection. This creates a robust and coordinated immune response that is necessary for effective pathogen clearance.
• Evaluate how memory T lymphocytes enhance immunological memory and their significance in vaccination strategies.
  • Memory T lymphocytes enhance immunological memory by remaining in the body after an infection has been resolved, allowing for rapid activation upon re-exposure to the same antigen. This is significant in vaccination strategies because vaccines aim to induce the formation of memory T cells without causing disease, leading to a faster and more effective response if the individual encounters the pathogen later. Thus, understanding memory T cell responses is crucial for developing effective vaccines against various infectious diseases.

Related terms

B lymphocytes: B lymphocytes, or B cells, are another type of white blood cell involved in the adaptive immune response, responsible for producing antibodies that neutralize pathogens.

Antigen: An antigen is any substance that triggers an immune response, typically a foreign protein found on the surface of pathogens or abnormal cells.

Cytokines: Cytokines are signaling proteins secreted by immune cells that mediate and regulate immunity, inflammation, and hematopoiesis.