Dendritic Cells

Definition

Dendritic cells are specialized antigen-presenting cells that play a crucial role in the adaptive immune response by capturing, processing, and presenting antigens to T cells. They act as a bridge between the innate and adaptive immune systems, helping to initiate and shape the immune response against pathogens. By doing this, dendritic cells are essential for activating T cells and ensuring that the immune system can respond effectively to infections.

5 Must Know Facts For Your Next Test

1. Dendritic cells are found in tissues throughout the body and are especially abundant in areas that are in contact with the external environment, such as the skin and mucosal surfaces.
2. Once dendritic cells capture antigens, they undergo maturation and migrate to lymph nodes, where they present the processed antigens to T cells.
3. They express major histocompatibility complex (MHC) molecules on their surface, which are critical for presenting antigens to T cells.
4. Dendritic cells can activate naive T cells, leading to their differentiation into effector T cells that carry out immune functions.
5. They also produce various cytokines that help regulate the immune response and influence other immune cell activities.

Review Questions

• How do dendritic cells capture and present antigens to T cells?
  • Dendritic cells capture antigens through a process called phagocytosis or endocytosis. After engulfing pathogens or their components, dendritic cells process these antigens internally and then present them on their surface using major histocompatibility complex (MHC) molecules. This presentation is crucial for the activation of T cells, as it allows them to recognize specific antigens and mount an appropriate immune response.
• Discuss the role of dendritic cells in bridging the innate and adaptive immune responses.
  • Dendritic cells serve as a vital link between the innate and adaptive immune systems. They are part of the innate immunity because they respond quickly to infections and can capture pathogens. After processing these pathogens, dendritic cells migrate to lymph nodes where they activate naive T cells, transitioning the response from an immediate innate reaction to a more targeted adaptive response. This role ensures a coordinated attack against pathogens while also shaping the specificity of the immune response.
• Evaluate the importance of dendritic cell maturation and migration for effective immune responses.
  • Dendritic cell maturation and migration are critical for effective immune responses because they dictate how well these cells can activate T cells. Upon capturing an antigen, dendritic cells mature by upregulating costimulatory molecules and cytokine production. This maturation is necessary for their function in lymph nodes, where they interact with T cells. If dendritic cells fail to migrate or mature properly, it can lead to inadequate activation of T cells, resulting in poor immunity against infections or even ineffective responses in vaccination scenarios.

Related terms

Antigen: A substance that induces an immune response, typically by being recognized by antibodies or T cell receptors.

T Cells: A type of white blood cell that is essential for the adaptive immune response, including helper T cells that assist other immune cells and cytotoxic T cells that kill infected or cancerous cells.

Innate Immunity: The body's first line of defense against pathogens, which includes physical barriers, immune cells, and various proteins that act immediately or within hours of an antigen's appearance.