Immunity to a Self-Derived, Channel-Forming Peptide in the Respiratory Tract

Department of Pathobiology, College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849, Department of Biochemistry and Department of Anatomy and Physiology, Kansas State University, Manhattan, Kansas 66506

^* To whom correspondence should be addressed. Email: vangifw{at}vetmed.auburn.edu.

	Abstract

The channel-forming peptide NC-1130 was generated based on the amino acid sequence of the M2-segment of the spinal cord -subunit of the glycine receptor and has been proposed as a therapeutic agent for anion channelopathies such as cystic fibrosis. Lysine adduction and amino acid substitutions at positions T19R and S22W of the peptide improved its performance as an ionchannel. However, these modifications generated an altered-self, potentially making this NC-1130 peptide immunogenic, which could preclude repeated use of NC-1130 as a therapeutic agent. To measure NC-1130 ability to induce an immune response, it was administered nasally with or without cholera toxin (CT). The NC-1130 peptide, when given alone without adjuvant, induced very little peptide-specific immunity based on analyses of peptide-specific antibodies by ELISA and ELISPOT assays, induction of cytokine production and delayed–type hypersensitivity (DTH) responses. Administration of peptide NC-1130 with the mucosal adjuvant CT induced peptide-specific IgG antibodies and DTH responses and a Th2-dominant cytokine response. The co-administration of the strong mucosal adjuvant CT induced a systemic NC-1130-specific IgG response but not a mucosal peptide-specific antibody response. The lack of peptide-specific immunity and specifically mucosal immunity should allow repeated NC-1130 peptide applications to epithelial surfaces to correct anion channelopathies.