The invention relates to a glycopeptide comprising between 1 and 40 repeated C-terminal polypeptides, with 11 amino acids, of BSDL or FAPP, whereby the aforementioned polypeptides are glycosylated and bear glycosylated epitopes giving rise to a specific immunological reaction with induced antibodies in a patient suffering from type 1 diabetes, and/or purified from biological fluids of human or animal origin or recombinant and produced by expression in a standard host cell comprising an enzymatic material necessary for priming a glycosylation, said host cell being genetically modified such as to comprise a gene coding for the aforementioned polypeptides and a gene coding for one or more enzymes selected from among glycosyltransferases and anti-glycopeptide antibodies. The invention also relates to the applications thereof in therapeutics and diagnostics.