Immunohistochemical labeling of normal melanocytes.

Comparison of seven antibodies for the demonstration of normal melanocytes in formalin-fixed, paraffin-embedded surgical discard skin showed that the monoclonal antibody Mel-5 (clone TA99) directed against pigment associated antigen was the most sensitive. Quantitative data were obtained for the sensitivity of the antibodies NKI/beteb, S100, T311, Melan A (clone A103), c-kit, and Mel-5 in parallel sections of human skin. An anticytokeratin antibody (CK34betaE12) was also used to stain basal keratinocytes and provide a negative image of the melanocytes present. Optimal conditions for the use of Mel-5 in paraffin sections of skin are described.