OPTION 4

Langerhans cell:

 

•            The Langerhans cell is another clear cell or dendritic cell found in the upper layers of the skin and the mucosal epithelium.

•            There is a correlation in the occurrence of stratum granulosum and Langerhans cells. The cell has a convoluted nucleus and characteristic rod-like granules in the cytoplasm, termed Birbeck granules.

•            This cell is free of melanin and does not give a dopa reaction. It stains with gold chloride, ATPase, and immunofluorescent markers.

•            The Langerhans cell is a cell of hematopoietic origin. Langerhans cells penetrate the epithelium from lamina propria. It has vimentin-type intermediate filaments. Langerhans cells are involved in the immune response.

•            In the presence of antigenic challenge by bacterial plaque Langerhans cells migrate into the gingiva. They also migrate into the epithelium in response to chemotactic factors released by the keratinocytes to the surface receptors of Langerhans cells. They contain la antigens, which they present to primed T cells (thymocytes). They may function, as do macrophages by picking up antigen and presenting it to lymphocytes, either locally or at lymph nodes.

•            Langerhans cells with HLA-DR and T6 antigens also interact with lymphocytes but do so differently from keratinocytes.

•            It has vimentin-type intermediate filaments.

•            Langerhans cells are involved in the immune response.

•            In the presence of antigenic challenge by bacterial plaque Langerhans cells migrate into the gingiva.

•            They also migrate into the epithelium in response to chemotactic

factors released by the keratinocytes to the surface receptors of Langerhans cells.

•            They contain la antigens, which they present to primed T cells (thymocytes).

•            They may function, as do macrophages by picking up antigen and presenting it to lymphocytes, either locally or at lymph nodes.

•            Langerhans cells with HLA-DR and T6 antigens also interact with lymphocytes but do so differently from keratinocytes.

•            Langerhans cells present the antigen to specific helper T cells. They shuttle between epithelium and regional lymph nodes.

•            The importance of these observations is that the skin and presumably the oral mucosa have an epithelial immunologic function, and through this function the epithelium of the skin and oral mucosa interacts with the entire lymphoid system in concert with the Langerhans cells to help mount an immune response.