Activated Langerhans Cells Release Tumor Necrosis Factor

摘要

Langerhans cell act as antigen presenting cells in immune reactions in the skin. What other roles they may play in inflammation are less well defined. We have tested whether these cells can produce TNF-alpha, an important mediator of inflammation. Resting Langerhans cells produce less than 0.1 U TNF-alpha/ml. Langerhans cells stimulated with phorbol myristate acetate (PMA) and lipopolysaccharide (LPS) release 4-5 U TNF-alpha/ml. Specificity of the released TNF-alpha in an L929 cytotoxicity assay was confirmed using neutralizing anti-TNF-alpha monoclonal antibodies, and the identity of TNF-alpha was further confirmed by Northern blot hybridization using a TNF-alpha oligomer DNA probe. Activated Langerhans cells may contribute to inflammation in the skin by releasing TNF-alpha, which is known to effect fibroblast growth, endothelial cell activation, and lymphocyte function. (KT)