Cytotoxic T-cells

Definition

Cytotoxic T-cells, also known as CD8+ T-cells, are a type of T-lymphocyte that play a crucial role in the adaptive immune response. These specialized cells are responsible for directly killing infected or cancerous cells, making them an essential component of the body's defense against various pathogens and diseases.

5 Must Know Facts For Your Next Test

1. Cytotoxic T-cells express the CD8 co-receptor on their surface, which allows them to recognize and bind to MHC class I molecules on the surface of infected or cancerous cells.
2. Upon recognition of their target, cytotoxic T-cells release cytotoxic granules containing perforin and granzymes, which induce apoptosis (programmed cell death) in the infected or cancerous cell.
3. Cytotoxic T-cells play a critical role in the body's defense against viral infections, as they can directly kill cells that have been hijacked by the virus and are producing viral proteins.
4. In addition to their role in fighting viral infections, cytotoxic T-cells are also important in the body's immune response to certain types of cancer, as they can recognize and destroy tumor cells.
5. The activation and differentiation of cytotoxic T-cells is a complex process that involves the interaction of various cytokines, co-stimulatory signals, and transcription factors, which ultimately leads to the generation of effector and memory T-cells.

Review Questions

• Explain the role of cytotoxic T-cells in the adaptive immune response.
  • Cytotoxic T-cells, also known as CD8+ T-cells, are a specialized type of T-lymphocyte that play a crucial role in the adaptive immune response. These cells are responsible for directly killing infected or cancerous cells, making them essential in the body's defense against various pathogens and diseases. Cytotoxic T-cells recognize their targets by binding to MHC class I molecules on the surface of infected or cancerous cells, which triggers the release of cytotoxic granules containing perforin and granzymes that induce apoptosis (programmed cell death) in the target cell. This process is a key mechanism in the body's ability to eliminate threats and maintain homeostasis.
• Describe the relationship between cytotoxic T-cells and helper T-cells (CD4+ T-cells) in the adaptive immune response.
  • Cytotoxic T-cells (CD8+ T-cells) and helper T-cells (CD4+ T-cells) work in tandem to orchestrate the adaptive immune response. While cytotoxic T-cells are responsible for directly killing infected or cancerous cells, helper T-cells play a crucial role in activating and supporting the function of cytotoxic T-cells. Helper T-cells recognize foreign antigens presented by antigen-presenting cells, such as dendritic cells, and then provide co-stimulatory signals and cytokines that promote the activation, proliferation, and differentiation of cytotoxic T-cells. This collaborative effort between the two T-cell subsets is essential for an effective and coordinated immune response against a wide range of threats.
• Analyze the significance of the Major Histocompatibility Complex (MHC) in the recognition and targeting of infected or cancerous cells by cytotoxic T-cells.
  • The Major Histocompatibility Complex (MHC) plays a crucial role in the recognition and targeting of infected or cancerous cells by cytotoxic T-cells. MHC class I molecules present peptide fragments derived from intracellular proteins, including those produced by viruses or tumor cells, on the surface of cells. Cytotoxic T-cells express the CD8 co-receptor, which allows them to recognize and bind to these MHC class I-peptide complexes. This interaction triggers the activation and cytotoxic response of the CD8+ T-cell, leading to the destruction of the infected or cancerous cell. The diversity of MHC class I molecules and their ability to present a wide range of peptides ensures that cytotoxic T-cells can recognize and respond to a vast array of threats, making the MHC-cytotoxic T-cell interaction a critical component of the adaptive immune system's defense against disease.

Related terms

T-cells:

T-cells, or T-lymphocytes, are a type of white blood cell that play a central role in the adaptive immune system, responsible for recognizing and responding to specific foreign antigens.

CD4+ T-cells: CD4+ T-cells, also known as helper T-cells, are a subtype of T-cells that assist other immune cells, such as B-cells and cytotoxic T-cells, in their immune response.

Major Histocompatibility Complex (MHC):

The Major Histocompatibility Complex (MHC) is a group of genes that encode proteins responsible for presenting foreign antigens to T-cells, allowing them to recognize and respond to threats.