Contaminant bands on SDS-polyacrylamide gel electrophoresis are recognised by antibodies in normal human serum and saliva.

Contamination of sodium dodecyl sulphate-polyacrylamide gel electrophoresis samples has commonly produced artefactual bands when sensitive detection systems, such as silver staining or immunoblotting procedures, have been used. Evidence suggests that these bands originate from human skin contamination of reagents and equipment. The presence of antibodies to contaminating bands, in serum and saliva samples from normal donors, detected in immunoblotting experiments, is described; the isotype distribution of these naturally occurring antibodies has also been investigated.