Flagellin as Carrier and Adjuvant in Cocaine Vaccine Development

Abstract

Cocaine abuse is problematic, directly and indirectly impacting the lives of millions, and yet existing therapies are inadequate and usually ineffective. A cocaine vaccine would be a promising alternative therapeutic option, but efficacy is hampered by variable production of anticocaine antibodies. Thus, new tactics and strategies for boosting cocaine vaccine immunogenicity must be explored. Flagellin is a bacterial protein that stimulates the innate immune response via binding to extracellular Toll-like receptor 5 (TLR5) and also via interaction with intracellular NOD-like receptor C4 (NLRC4), leading to production of pro-inflammatory cytokines. Reasoning that flagellin could serve as both carrier and adjuvant, we modified recombinant flagellin protein to display a cocaine hapten termed GNE. The resulting conjugates exhibited dose-dependent stimulation of anti-GNE antibody production. Moreover, when adjuvanted with alum, but not with liposomal MPLA, GNE-FliC was found to be better than our benchmark GNE-KLH. This work represents a new avenue for exploration in the use of hapten-flagellin conjugates to elicit antihapten immune responses.

The Impact of Bioinformatics on Vaccine Design and Development

“…Their computational results agreed with those used for experimentation since then in a TLR5 reporter assay: the modiied lagellin protein still activated TLR5 when the hapten density was <10 GNE per FliC. Finally, the authors showed that cocaine-lagellin conjugates induced, in a dose-dependent model, the production of anticocaine antibodies in mice, improving the response with the adjuvant alum [73,74].…”

“…Again, bioinformatics was necessary to assess the secondary structure and MHC-II binding predictions for FliC and mFliC, employing the PSIPRED (htp://bioinf. cs.ucl.ac.uk/psipred/) method and the external software from IEDB (htp://www.immunoepitope.org/), respectively [74].…”

“…However, because FliC and mFliC exhibited poor eicacy as carrier proteins when comparing two formulations, GNE-FliC + CpG and GNE-TT + CpG, through a hyperlocomotion test and analysis of cocaine in blood, where GNE-TT + CpG had best eicacy, the authors proposed the investigation of monomers of FliC instead of the polymeric form utilized [74].…”

Heat shock proteins: A dual carrier-adjuvant for an anti-drug vaccine against heroin

“…11-12 In the field of vaccine development, new adjuvants are highly sought after that can stimulate a robust humoral immune response. 13-14 …”

Biologics to treat substance use disorders: Current status and new directions

“…99 A cocaine hapten conjugated to the TLR5 agonist flagellin elicited greater cocaine-specific Ab concentrations than the same hapten conjugated to KLH. 100 A novel nicotine vaccine employed a peptide-based trimeric coiled-coil (TCC) carrier containing CD4 C T cell epitopes.…”