title: Highly purified mutant E112K of cholera toxin elicits protective lung mucosal immunity to diphtheria toxin.
abstract: We demonstrated that the mutant of cholera toxin (mCT) E112K which was LPS-free supported the induction of protective immunity in mucosal (e.g. lung lavage) and systemic (e.g. serum) compartments when given nasally with vaccine-grade diphtheria toxoid (DT) to mice. Significant DT-specific mucosal IgA antibody (Ab) and serum IgG, IgA and IgM Ab responses were induced when LPS-depleted mCT E112K or native CT (nCT) was co-administered nasally with DT. The analysis of DT-specific Ab-forming cell (AFC) responses supported the Ab titers and significant numbers of DT-specific IgA AFC were present in the lungs, nasal passages and submandibular glands. Furthermore, DT-specific IgG AFC in cervical lymph nodes (CLN) and the spleen were induced in mice administered with DT nasally with either mCT or nCT. The analysis of antigen-specific T cell responses revealed that increased DT-specific CD4+ T cell proliferative and Th2-type cytokine responses were induced in mice nasally-immunized with DT and the LPS-free form of mCT. The neutralization of diphtheria toxin by Abs showed that DT-specific IgG Ab responses in serum and lung lavages of mice immunized with DT and mCT were protective. Furthermore, it was shown that an IgA-enriched fraction of lung lavages possessed diphtheria toxin-specific neutralizing activity. These results are the first demonstration that nasally co-administered mCT E112K can induce DT-specific protective Ab responses in mucosal compartments (e.g. lung lavages and the lungs).
authors.affiliation: Department of Bacteriology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Niigata 951-8510, Japan. mario@med.niigata-u.ac.jp
authors.forename: M
authors.initials: M
authors.lastname: Ohmura
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: H
authors.initials: H
authors.lastname: Kiyono
authors.forename: K
authors.initials: K
authors.lastname: Fujihashi
authors.forename: Y
authors.initials: Y
authors.lastname: Takeda
authors.forename: J R
authors.initials: JR
authors.lastname: McGhee
mesh_terms: D000281:Administration, Intranasal; D000818:Animals; D000907:Antibodies, Bacterial / Q000096:biosynthesis; D000921:Antibody-Producing Cells / Q000276:immunology; D002772:Cholera Toxin / Q000008:administration & dosage / Q000235:genetics* / Q000494:pharmacology*; D004167:Diphtheria Toxin / Q000008:administration & dosage / Q000276:immunology*; D018928:Immunity, Mucosal / Q000187:drug effects*; D007070:Immunoglobulin A / Q000096:biosynthesis; D007074:Immunoglobulin G / Q000096:biosynthesis; D008168:Lung / Q000187:drug effects* / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D016297:Mutagenesis, Site-Directed; D009500:Neutralization Tests; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D004167:Diphtheria Toxin; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D002772:Cholera Toxin