THE ADJUVANT EFFECT OF A NONTOXIC MUTANT OF HEAT-LABILE ENTEROTOXIN OF ESCHERICHIA-COLI FOR THE INDUCTION OF MEASLES VIRUS-SPECIFIC CTL RESPONSES AFTER INTRANASAL CO-IMMUNIZATION WITH A SYNTHETIC PEPTIDE

The intranasal route has been shown to be effective for immunization. However, immunization via this route may require the use of potent and safe adjuvant. The construction of non-toxic mutants of heat labile e nterotoxin of Escherichia coli (LT), which is a potent mucosal adjuvan t, is a major breakthrough for the development of mucosal vaccines. In this study we have assessed the ability of an LT mutant (LTK63) to ac t as an adjuvant following intranasal co-immunization with a peptide c orresponding to a measles virus cytotoxic T lymphocyte (CTL) epitope. LTK63 was more effective at potentiating the in vivo induction of pept ide-specific and measles virus-specific CTL responses than was adminis tration of the peptide in saline. A concentration of 10 mu g/dose of L TK63 was found to be the most effective in potentiating the in vivo pr iming of peptide-specific and measles virus-specific CTL responses. Th ese findings highlight the potential of the non-toxic mutant of LT as a safe mucosal adjuvant for use in humans.