Which cells are primary immune cells in the epidermis?

Which cells are primary immune cells in the epidermis?

• A. Melanocytes
• B. Keratinocytes
• C. Langerhans cells
• D. Fibroblasts

Answer: (C)

Antigen presentation in the epidermis is carried out primarily by Langerhans cells. These are specialized dendritic cells that reside in the epidermal layers, constantly sampling for antigens that breach the skin barrier. After capturing and processing these antigens, they migrate to regional lymph nodes and present peptide fragments to naive T cells using MHC class II molecules, delivering the necessary co-stimulatory signals to activate adaptive immunity. This role makes them the key immune players within the epidermis. Melanocytes are pigment-producing cells, keratinocytes mainly form and maintain the barrier (and can participate in signaling), and fibroblasts reside in the dermis, contributing to structural support rather than primary immune functions in the epidermis.

Antigen presentation in the epidermis is carried out primarily by Langerhans cells. These are specialized dendritic cells that reside in the epidermal layers, constantly sampling for antigens that breach the skin barrier. After capturing and processing these antigens, they migrate to regional lymph nodes and present peptide fragments to naive T cells using MHC class II molecules, delivering the necessary co-stimulatory signals to activate adaptive immunity. This role makes them the key immune players within the epidermis. Melanocytes are pigment-producing cells, keratinocytes mainly form and maintain the barrier (and can participate in signaling), and fibroblasts reside in the dermis, contributing to structural support rather than primary immune functions in the epidermis.