Intranasal or subcutaneous co-administration of recombinant cholera toxin B subunit stimulates only a slight or no level of the specific IgE response in mice to tetanus toxoid.

Whether recombinant cholera toxin B subunit (rCTB) co-administered intranasally or subcutaneously with aluminium-non-adsorbed tetanus toxoid (nTT) can induce the production of tetanus toxoid (TT)-specific IgE antibodies in mice was investigated compared with aluminium-adsorbed tetanus toxoid (aTT) administered intranasally or subcutaneously. Mice immunized intranasally or subcutaneously with nTT together with rCTB showed a high level of TT-specific serum IgG antibody response and no or a slight level of TT-specific serum IgE antibody response. On the other hand, in mice vaccinated intranasally or subcutaneously with aTT alone, higher levels of TT-specific IgG and IgE antibodies were induced in comparison with intranasal or subcutaneous inoculation of nTT together with rCTB. These results suggest that intranasal or subcutaneous co-administration of rCTB with nTT is better than intranasal or subcutaneous administration of aTT to avoid IgE-mediated allergic reactions.