Effect of glycosylation of a synthetic MUC1 mucin-core-related peptide on recognition by anti-mucin antibodies.

Human epithelial mucins are heterogeneously glycosylated proteins associated with breast and ovarian cancer. Several peptide-reactive anti-mucin MUC1 monoclonal antibodies are used in experimental and diagnostic assays but it is not known how glycosylation of the mucin influences antibody recognition. In this report we show that increasing glycosylation of a synthetic 25-amino acid fragment of the MUC1 core protein with N-acetylgalactosamine (GalNAc) elicits different responses in its recognition by two anti-MUC1 antibodies, C595 and HMFG1. We propose that increasing glycosylation of the synthetic mucin fragment produces an alteration in the structure of the epitope which enhances binding in C595, but not in HMFG1.