The specificity of this monoclonal antibody to its intended target was validated by HuProt™ Array, containing more than 19, 000, full-length human proteins. S100 belongs to the family of calcium binding proteins. S100A and S100B proteins are two members of the S100 family. S100A is composed of an alpha and a beta chain whereas S100B is composed of two beta chains. This antibody is specific against an epitope located on the alpha-chain (i. e. in S-100A and S-100B) but not on the beta-chain of S-100 (i. e. in S-100B). This antibody can be used to localize S-100A in various tissue sections. S-100 protein has been found in normal melanocytes, Langerhans cells, histiocytes, chondrocytes, lipocytes, skeletal and cardiac muscle, epithelial and myoepithelial cells of the breast, salivary and sweat glands. Neoplasms derived from these cells also express S-100 protein. Almost all malignant melanomas and cases of histiocytosis X are positive for S-100 protein. Primary antibodies are available purified, or with a selection of fluorescent CF® Dyes and other labels. CF® Dyes offer exceptional brightness and photostability. Note: Conjugates of blue fluorescent dyes like CF®405S and CF®405M are not recommended for detecting low abundance targets, because blue dyes have lower fluorescence and can give higher non-specific background than other dye colors.