Langerhans cells

Definition

Langerhans cells are specialized immune cells found in the skin, primarily in the epidermis, that play a crucial role in the body's immune response. These dendritic cells are involved in detecting and presenting antigens to T-cells, acting as sentinels for skin infections and contributing to the skin's overall function as a barrier against pathogens. They also help to mediate allergic reactions and maintain immune tolerance.

5 Must Know Facts For Your Next Test

1. Langerhans cells are named after Paul Langerhans, who first described them in 1868.
2. They originate from bone marrow and migrate to the skin, where they become embedded in the epidermis.
3. Langerhans cells can recognize pathogens through pattern recognition receptors (PRRs), enhancing their ability to respond to infections.
4. When activated, these cells can migrate to lymph nodes to activate T-cells, playing a vital role in adaptive immunity.
5. These cells also contribute to skin homeostasis by participating in wound healing and maintaining the balance of skin flora.

Review Questions

• How do Langerhans cells contribute to the skin's immune defense?
  • Langerhans cells act as the first line of defense in the skin's immune system by detecting and capturing pathogens. They reside in the epidermis, where they constantly monitor for harmful invaders. Once they recognize an antigen, they process it and present it to T-cells, which activates a broader immune response. This interaction is crucial for protecting the body from infections and initiating appropriate immune reactions.
• Discuss the relationship between Langerhans cells and allergic reactions.
  • Langerhans cells play a significant role in mediating allergic reactions by recognizing allergens and presenting them to T-cells. When exposed to an allergen, these cells become activated and release cytokines that attract other immune cells to the site. This process can lead to inflammation and symptoms associated with allergic responses. Their function in this context highlights their importance not only in detecting pathogens but also in managing inappropriate immune responses to non-harmful substances.
• Evaluate the impact of Langerhans cell dysfunction on skin health and immunity.
  • Dysfunction of Langerhans cells can have serious implications for both skin health and overall immunity. If these cells fail to recognize or present antigens effectively, it may result in an increased susceptibility to infections, as the body cannot mount an adequate immune response. Additionally, impaired function can lead to autoimmune disorders or chronic inflammation in the skin, contributing to conditions like eczema or psoriasis. Understanding these impacts emphasizes the importance of Langerhans cells in maintaining both local and systemic immune balance.

Related terms

Epidermis: The outermost layer of skin that provides a barrier against environmental factors and houses various types of cells, including Langerhans cells.

Dendritic cells: A type of antigen-presenting immune cell that helps initiate and regulate the immune response, with Langerhans cells being a specific type found in the skin.

Antigen presentation: The process by which Langerhans cells capture, process, and display antigens on their surface to T-cells, initiating an immune response.