Human epidermal Langerhans cells induce cellular immune response to trichophytin in dermatophytosis

Human epidermal cell suspensions were prepared from patients sensitized to trichophytin. The cells were 75% to 95% viable, and contained 2% to 6% Langerhans cells as judged by immunofluorescence staining with an anti-DR antiserum. T lymphocytes from the same patients were co-cultured with trichophytin, with or without epidermal cells or macrophages. Proliferative T-cell response to trichophytin was obtained in cultures containing epidermal cells or macrophages. Pretreatment of the epidermal cells with anti-DR antiserum abolished the response, but normal rabbit serum did not, indicating that HLA-DR positive Langerhans cells are able to induce the cellular immune response to trichophytin. These data indicate that Langerhans cells play an important role in dermatophytosis.