Intranasal immunization with a recombinant truncated FimH adhesin adjuvanted with CpG oligodeoxynucleotides protects mice against uropathogenic Escherichia coli challenge

In this work, we assessed the efficacy of an experimental intranasal vaccine against urinary-tract infections. The vaccine contained a recombinant truncated FimH (rFimHt) adhesin plus CpG oligodeoxynucleotides. The efficacy of the vaccine was compared with that of an intramuscular vaccine that was formulated with the same immunogen plus Freund's adjuvant. Our results show that serum immunoglobulin G titers of vaccinated animals were similarly enhanced in both cases. However, the intranasal vaccine elicited higher vaginal-wash-specific immunoglobulin A titers against rFimHt than the intramuscular route. Both vaccines reduced the in vivo colonization of the bladder by uropathogenic Escherichia coli more than 100-fold in a murine cystitis model. Our results indicate that a recombinant truncated FimH adhesin plus CpG oligodeoxynucleotides is a suitable immunogenic combination that can contribute to the development of a highly efficacious urinary tract infection vaccine.