Dendritic cells

Definition

Dendritic cells are specialized antigen-presenting cells that play a crucial role in initiating and modulating the immune response. They act as a bridge between the innate and adaptive immune systems, capturing and processing antigens from pathogens, then presenting them to T cells to activate an adaptive immune response. Their ability to migrate to lymph nodes and interact with T cells makes them essential for generating immunity and maintaining immune tolerance.

5 Must Know Facts For Your Next Test

1. Dendritic cells originate from bone marrow and can be found in tissues that are in contact with the external environment, like the skin and mucosal surfaces.
2. They capture antigens through processes like phagocytosis or endocytosis before migrating to lymph nodes to present these antigens to T cells.
3. There are several types of dendritic cells, including conventional dendritic cells and plasmacytoid dendritic cells, each playing distinct roles in the immune response.
4. Dendritic cells also secrete cytokines that help shape the adaptive immune response, influencing T cell differentiation into specific subtypes.
5. These cells are crucial for tolerance mechanisms as well, helping to prevent autoimmune responses by presenting self-antigens to T cells.

Review Questions

• How do dendritic cells function as a link between the innate and adaptive immune systems?
  • Dendritic cells act as a crucial connector between the innate and adaptive immune systems by capturing antigens from pathogens during the initial immune response. After processing these antigens, they migrate to lymph nodes where they present the processed antigens to T cells. This presentation is key for activating T cells and triggering a more specific adaptive immune response, which leads to long-lasting immunity.
• Discuss the significance of cytokine secretion by dendritic cells in shaping the immune response.
  • Cytokine secretion by dendritic cells is significant because it influences how T cells differentiate and respond to antigens. Depending on the types of cytokines released, dendritic cells can promote various T cell subsets, such as Th1, Th2, or regulatory T cells. This ability to modulate T cell responses is essential for tailoring the immune reaction appropriately based on the pathogen encountered and can also help maintain immune tolerance.
• Evaluate the role of dendritic cells in preventing autoimmune diseases through their interaction with T cells.
  • Dendritic cells play a critical role in preventing autoimmune diseases by mediating tolerance through their interactions with T cells. By presenting self-antigens alongside signals that promote tolerance rather than activation, dendritic cells can induce anergy or apoptosis in self-reactive T cells. This process helps maintain a balance in the immune system, preventing inappropriate responses against the body's own tissues and thereby reducing the risk of autoimmune disorders.

Related terms

Antigen-presenting cells (APCs): Cells that display antigens on their surface for recognition by T cells, including dendritic cells, macrophages, and B cells.

T cells: A type of lymphocyte that plays a central role in cell-mediated immunity, responsible for recognizing and responding to antigens presented by APCs.

Innate immunity: The first line of defense against pathogens, involving non-specific responses such as inflammation and the activity of various immune cells, including dendritic cells.