Immunoblot analysis of the specificity of the antibody: the proteins of several samples were separated by SDS-PAGE under reducing conditions, and transferred to a filter. Then, the filter was incubated with antibody against human lysozyme and developed. The proteins recognized by the antibody appear as dark bands against a uniform background. Molecular mass markers are indicated on the left of the gel but not shown in the gel itself. lysoz. = lysozyme.