RESUMO
Langerhans cells (LCs) represent a unique DC subset populating the outermost body surface, i.e., the epidermis. Although CD1a and langerin (CD207) are used as specific markers to distinguish LCs from other DC subsets, their immunological functions have remained mostly unknown. A new paper (see the related article beginning on page 701) demonstrates that LCs utilize these markers to induce cellular immune responses to Mycobacterium leprae: CD1a mediates the presentation of nonpeptide antigens to T cells, while langerin facilitates uptake of microbial fragments and perhaps their delivery to a specialized subcellular compartment.
Assuntos
Antígenos CD1/fisiologia , Antígenos de Superfície/fisiologia , Ilhotas Pancreáticas/citologia , Lectinas Tipo C/fisiologia , Lectinas de Ligação a Manose/fisiologia , Animais , Apresentação de Antígeno , Antígenos/química , Antígenos CD , Transporte Biológico , Humanos , Lectinas/química , Lipídeos/química , Modelos Biológicos , Mycobacterium leprae/patogenicidadeRESUMO
Langerhans cells (LCs) constitute a subset of DCs that initiate immune responses in skin. Using leprosy as a model, we investigated whether expression of CD1a and langerin, an LC-specific C-type lectin, imparts a specific functional role to LCs. LC-like DCs and freshly isolated epidermal LCs presented nonpeptide antigens of Mycobacterium leprae to T cell clones derived from a leprosy patient in a CD1a-restricted and langerin-dependent manner. LC-like DCs were more efficient at CD1a-restricted antigen presentation than monocyte-derived DCs. LCs in leprosy lesions coexpress CD1a and langerin, placing LCs in position to efficiently present a subset of antigens to T cells as part of the host response to human infectious disease.