Complementary peptides against the major epitope in the NC16A domain of BP180 show no specificity as vaccines to bullous pemphigoid

A stretch of 14 amino acids (542-555) (MCW-1) in the NC16A domain of BP180 has been shown to be an immunogenic and pathogenic epitope for bullous pemp higoid (BP). Therefore, it provides an excellent target for treatment throu gh a complementary peptide approach, which has been established in other au toimmune diseases, including experimental autoimmune myasthenia gravis. We examined two synthetic complementary peptides BP3CP5 and BP5CP3 against thi s region. These peptides were derived, respectively, by reading the antisen se RNA of this region of BP180 in 3'-5' and 5'-3' directions. We found evid ent complementarities in hydropathic scores between MCW-1 and both compleme ntary peptides. However. by enzyme-linked immunosorbent assay (ELISA), the complementary peptides BP3CP5 and BP5CP3 did not bind to either synthetic p eptide BPNP or glutathione-S-transferase (GST) fusion proteins BP180NC16a a nd GST-BP-1050. BPNP, BP180NC16a and GST-BP-1050 cover the MCW-1 region of BP180 and were used as the natural peptides in this study. In addition, nei ther BP3CP5 nor BP5CP3 blocked the reaction between BPNP and anti-BPNP anti body, nor did they block immunofluorescent staining of the basement membran e zone by BP sera. Pre-incubation with BP3CP5 and BP5CP3 did not block the binding of BP sera to the BP180NC16a fusion protein in immunoblotting. Furt hermore, rabbit antisera raised against BP3CP5 and BP5CP3 did not bind BP s era in ELISA. Pre-incubation with these rabbit antisera did not inhibit or reduce the binding of BP sera to the autoantigen in either immunoblotting o r immunofluorescence. Thus, we concluded that complementary peptides agains t this particular epitope in BP180 NC16A domain showed no specificity as va ccines to BP, although this approach should be tried for other epitopes in various autoimmune bullous diseases. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.