Oral administration of influenza vaccine in combination with the adjuvantsLT-K63 and LT-R72 induces potent immune responses comparable to or stronger than traditional intramuscular immunization

Mucosal immunization strategies are actively being pursued in the hopes of improving the efficacy of vaccines against the influenza virus. Our group i nvestigated the oral immunization of mice via intragastric gavage with infl uenza hemagglutinin (HA) combined with mutant Escherichia coli heat-labile enterotoxins K63 (LT-K63) and R72 (LT-R72), These oral immunizations result ed in potent serum antibody and HA inhibition titers, in some cases stronge r than those obtained with traditional intramuscular administration, in add ition to HA-specific immunoglobulin A in the saliva and nasal secretions. T his study demonstrates that it may be possible to develop effective oral in fluenza vaccines.