Induction of systemic and mucosal antibody responses in mice immunized intranasally with aluminium-non-adsorbed diphtheria toxoid together with recombinant cholera toxin B subunit as an adjuvant. Vaccine 18:743–751

Abstract

Abstract Nasal mucosal immunization is very attractive for vaccination to prevent various bacterial and viral infectious diseases because of induction of systemic and mucosal immune responses. The aim of the present study was to investigate the possibility of changing the immunization procedure of diphtheria toxoid (DT) from intramuscular or subcutaneous injection to intranasal administration. Intranasal immunization with aluminium-non-adsorbed diphtheria toxoid (nDT) together with recombinant cholera toxin B subunit (rCTB, 10 mg) induced, at a concentration of 5 Lf, high levels of serum DT-speci®c IgG antibody responses and high or moderate levels of the speci®c IgA antibody responses in all mice and only a slight level of the speci®c IgE antibody responses in some mice. Furthermore, suciently high diphtheria antitoxin titres more than 0.1 international units (IU) ml À1 were obtained from mice which showed high levels of serum DT-speci®c IgG antibody responses. Under the same experimental conditions, induction of signi®cant levels of mucosal DT-speci®c IgA antibody responses occurred in the nasal cavity, the lung, the saliva and vaginal secretions and the small and large intestines of all mice, although there were dierent titres between individual mice. Similar results were also obtained with rCTB-speci®c serum IgG and IgA and mucosal IgA antibody responses; serum rCTB-speci®c IgE antibody titres were not detected. These results show that intranasal administration of nDT with rCTB must be a very useful means for vaccination against diphtheria.