Lipid conjugation of TLR7 agonist Resiquimod ensures co-delivery with the liposomal Cationic Adjuvant Formulation 01 (CAF01) but does not enhance immunopotentiation compared to non-conjugated Resiquimod+CAF01


Pattern recognition receptors, including the Toll-like receptors (TLRs), are important in the induction and activation of two critical arms of the host defence to pathogens and microorganisms; the rapid innate immune response (as characterised by the production of Th1 promoting cytokines and type 1 interferons) and the adaptive immune response. Through this activation, ligands and agonists of TLRs can enhance immunotherapeutic efficacy. Resiquimod is a small (water-soluble) agonist of the endosome-located Toll-like receptors 7 and 8 (TLR7/8). However due to its molecular attributes it rapidly distributes throughout the body after injection. To circumvent this, these TLR agonists can be incorporated within delivery systems, such as liposomes, to promote the co-delivery of both antigen and agonists to antigen presenting cells. In this present study, resiquimod has been chemically conjugated to a lipid to form a lipid-TLR7/8 agonist conjugate which can be incorporated within immunogenic cationic liposomes composed of dimethyldioctadecylammonium bromide (DDA) and the immunostimulatory glycolipid trehalose 6,6′ – dibehenate (DDA:TDB). This DDA:TDB-TLR7/8 formulation offers similar vesicle characteristics to DDA:TDB (size and charge) and offers high retention of both resiquimod and the electrostatically adsorbed TB subunit antigen Ag85B-ESAT6-Rv2660c (H56). Following immunisation through the intramuscular (i.m.) route, these cationic liposomes form a vaccine depot at the injection site. However, immunisation studies have shown that this biodistribution does not translates into notably increased antibody nor Th1 responses at the spleenand draining popliteal lymph node. This work demonstrates that the conjugation of TLR7/8 agonists to cationic liposomes can promote co-delivery but the immune responses stimulated do not merit the added complexity considerations of the formulation.

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Divisions: College of Health & Life Sciences > Aston Pharmacy School
College of Health & Life Sciences > School of Biosciences > Cell & Tissue Biomedical Research
College of Health & Life Sciences
Additional Information: © 2018, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Publication ISSN: 1873-4995
Last Modified: 10 Jun 2024 07:29
Date Deposited: 10 Oct 2018 12:20
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Related URLs: https://linking ... 16836591830573X (Publisher URL)
PURE Output Type: Article
Published Date: 2018-12-10
Published Online Date: 2018-10-03
Accepted Date: 2018-10-01
Authors: Wilkinson, Alexander
Lattmann, Eric
Roces, Carla B.
Pedersen, Gabriel
Christensen, Dennis
Perrie, Yvonne

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