The present invention provides improved methods and compositions for treating and preventing autoimmune and allergic diseases. More specifically, the invention relates to new immunomodulating complexes that are fusion proteins comprising a mutant subunit of the A1-subunit of the cholera toxin (CTA1), a peptide capable of binding to a specific cellular receptor, and one or more epitopes associated with an autoimmune or allergic disease. In the mutant CTA1 subunit, the amino acids corresponding to the amino acid 7, arginine, and amino acid 187, cysteine, in the native CTA1 have been replaced.