Clostridium difficile toxin peptide acts as mucosal adjuvant.

2004 JUL 7 - (NewsRx.com & NewsRx.net) -- Clostridium difficile toxin A carboxyl-terminus peptide lacking ADP-ribosyltransferase activity acts as a mucosal adjuvant.

"The receptor binding domains of the most potent mucosal adjuvants, bacterial toxins and plant lectins, are organized in repeat units to recognize specific sugar residues. The lectin-like structure of the C-terminal region of Clostridium difficile toxin A prompted us to investigate the mucosal adjuvant properties of a nontoxigenic peptide corresponding to amino acids 2394 to 2706 (TxA[subscript]C314). We compared TxA[subscript]C314 adjuvant activity to those of cholera toxin (CT) and Escherichia coli heat-labile enterotoxin subunit B (EtxB) co-administered orally or nasotracheally with poor peptide antigens (keyhole limpet hemocyanin [KLH] and hen egg lysozyme [HEL])," investigators in Italy report.

"Levels of anti-KLH-specific serum immunoglobulin G (IgG) and IgA as well as that of mucosal IgA were significantly higher in animals immunized orally with TxA[subscript]C314 plus KLH than with KLH alone, CT plus KLH, or EtxB plus KLH," said Ignazio Castagliuolo and colleagues at the University of Padua. "Following intranasal immunization with TxA[subscript]C314 plus HEL, levels of serum- and mucosa-specific antibodies were comparable to those induced by co-administering HEL with CT or EtxB. The TxA[subscript]C314 adjuvant effect following oral, but not intranasal, immunization was dose dependent."

"The analysis of the subclasses of anti-KLH-specific IgG ...