Langerhans cells cross-present antigen derived from skin

Area of Science:

• Immunology
• Dermatology
• Cell Biology

Background:

• Dendritic cells (DCs) are known for cross-presentation of exogenous antigens on MHC class I to CD8+ T cells.
• Langerhans cells (LCs), the primary DCs in the epidermis, have poorly understood cross-presentation capabilities.

Purpose of the Study:

• To investigate the capacity of murine Langerhans cells (LCs) to cross-present exogenous antigens.
• To determine the functional consequences of LC-mediated cross-presentation on CD8+ T cells.
• To assess the potential role of LCs in epicutaneous vaccination.

Main Methods:

• Isolation and in vitro culture of murine LCs.
• Assessment of antigen cross-presentation using ovalbumin protein and peptide.
• Utilizing transporter associated with antigen processing (TAP)-1-deficient mice.
• In vivo studies involving epicutaneous antigen application and T cell proliferation assays.

Main Results:

• Isolated LCs demonstrated cross-presentation of soluble and cell-associated ovalbumin on MHC class I to CD8+ T cells.
• Cross-presentation by LCs was less potent than spleen-derived CD8+ DCs but involved a TAP-dependent pathway.
• Migratory LCs ingested epidermal antigens and presented them to T cells.
• LC cross-presentation induced IFN-gamma production and cytotoxicity in antigen-specific CD8+ T cells.
• Epicutaneous ovalbumin application led to in vivo OT-I T cell proliferation, enhanced by skin inflammation.

Conclusions:

• Langerhans cells are capable of cross-presenting exogenous antigens to CD8+ T cells, inducing effector functions.
• LCs contribute to immune surveillance in the skin and may play a crucial role in epicutaneous vaccination.