Among the following, which cells assist in immune responses?

Langerhans cells play a crucial role in the immune system as specialized antigen-presenting cells. They are a type of dendritic cell found primarily in the skin's epidermis and act as sentinels, detecting and capturing pathogens that invade the skin. Once they recognize antigens—substances that provoke an immune response—they migrate to the lymph nodes and present these antigens to T cells. This process is vital for triggering adaptive immune responses, enabling the body to recognize and combat foreign invaders effectively.

In contrast to Langerhans cells, keratinocytes primarily function in forming a protective barrier against environmental damage and pathogens, but they do not directly orchestrate immune responses. Fibroblasts are mainly involved in the structural framework of tissues and do not play a direct role in immune function. Melanocytes are responsible for the production of melanin, which protects against UV damage, but they have no direct involvement in immune responses. Thus, Langerhans cells are distinct as the key players in modulating and facilitating immune reactions within the skin.