**Question:** Antigen presenting cells present in skin are called

A. Dendritic cells
B. Langerhans cells
C. Macrophages
D. Natural killer cells

**Core Concept:** Antigen presenting cells (APCs) are specialized immune cells that play a crucial role in initiating immune responses by presenting antigens to T cells. In the skin, two main types of APCs are present: dendritic cells and Langerhans cells. These cells are essential for maintaining skin immune surveillance and preventing infections.

**Why the Correct Answer is Right:** Dendritic cells and Langerhans cells are both types of APCs that function in antigen presentation and immune surveillance within the skin. They serve as the first line of defense against pathogens and help to initiate a specific immune response.

**Why Each Wrong Option is Incorrect:**

**Option A (Natural killer cells):** Natural killer cells are part of the innate immune system and primarily target virus-infected cells and tumor cells. Although they can also present antigens, they are not the primary antigen presenting cells in the skin.

**Option B (Macrophages):** Macrophages are part of the innate immune system and are found throughout the body. While they can present antigens, the focus in the skin is on dendritic cells and Langerhans cells, which are more specific to the skin microenvironment.

**Option C (Dendritic cells):** Although dendritic cells are antigen presenting cells in the skin, Langerhans cells, a subset of dendritic cells, are specifically associated with the skin and play a crucial role in skin immune surveillance.

**Clinical Pearl:** Langerhans cells, being a part of the skin's immune system, play a vital role in maintaining skin health by detecting and responding to pathogens and foreign substances. Their presence in the skin ensures efficient immune surveillance and helps prevent infections and skin diseases.

**Correct Answer:** B. Langerhans cells

Explanation: Among the available options, Langerhans cells are the correct answer as they are a specific subset of dendritic cells that reside in the skin and play a crucial role in immune surveillance. They are responsible for presenting antigens to T cells, initiating an adaptive immune response, and maintaining skin health by detecting and responding to pathogens and foreign substances.