Immunogenicity of IRIV- versus alum-adjuvanted diphtheria and tetanus toxoid vaccines in influenza primed mice

The immunogenicity and protectivity of two different toroid vaccines were c ompared in mice. In one formulation, toxoids (diphtheria or tetanus) were a dsorbed to alumoxid, whereas in the other formulation the toxoids were cros slinked to immunopotentiating reconstituted influenza virosomes (IRIVs). A preimmunization with influenza antigens is necessary for a good anti-toroid antibody response when the IRIV formulation was administered. After two im munizations with the IRIV- or alum-based vaccines, the IRIV-based formulati on induced a higher humoral immune response than toxoids adsorbed to alum. Using an in vitro test, diphtheria toxin neutralizing antibodies were teste d. Di-IRIV induced a significantly (p = 0.002) higher titer of diphtheria t oxin neutralizing antibodies than Di-alum. Tetanus challenge experiments sh owed, that the IRIV-based tetanus vaccine induced a threefold higher titer of protective antibodies than the tetanus toroid adsorbed to alum. Therefor e, the IRIV-based formulations appeared to be superior to the alum-based va ccines in terms of immunogenicity and protectivity. (C) 1999 Elsevier Scien ce Ltd. All rights reserved.