Which type of cells are derived from red bone marrow, migrate to the epidermis, and are involved in immune responses?

Langerhans cells are specialized immune cells that originate from red bone marrow and migrate to the epidermis, the outermost layer of the skin. These cells play a crucial role in the body's immune response by identifying and presenting antigens to T-cells, thus initiating an immune reaction. They act as sentinels, detecting pathogens and foreign substances that may invade the skin.

In contrast, keratinocytes are the predominant cell type in the epidermis and are responsible for the formation of the skin barrier through the production of keratin. Melanocytes, another type of epidermal cell, are responsible for producing melanin, the pigment that gives skin its color and provides protection against UV radiation. Merkel cells, found in the epidermis, are involved in the sensation of touch but do not have a direct role in immune responses.

Therefore, Langerhans cells are uniquely suited to the immune function described in the question due to their origin, migration pattern, and role in presenting antigens within the skin.