Biodegradable Hyaluronic Acid Modified with Tetraglycine-l-octaarginine as a Safe Adjuvant for Mucosal Vaccination

Abstract

We have been investigating the potential use of polymers modified with cell-penetrating peptides as an adjuvant for mucosal vaccination and have already developed nondegradable poly(N-vinylacetamide-co-acrylic acid) (PNVA-co-AA) with which D-octaarginine, a typical cell-penetrating peptide, was grafted. Our previous murine infection experiments demonstrated that immunoglobulin G (IgG) and immunoglobulin A (IgA) were induced in systemic circulation and secreted on nasal mucosa, respectively, through 4-time nasal inoculations with a mixture of influenza viral antigens and D-octaarginine-linked PNVA-co-AA at 7-day intervals, and that immunized mice were perfectly protected from homologous virus infection. In the present study, we designed novel biodegradable polymers bearing cell-penetrating peptides from a perspective of clinical application. Hyaluronic acid whose glucuronic acid was modified with tetraglycine-L-octaarginine at a monosaccharide unit ratio of 30% was successfully developed. The hyaluronic acid derivative exhibited adjuvant activities identical to PNVA-co-AA bearing either D-octaarginine or tetraglycine-D-octaarginine under the above-mentioned inoculation schedule. We further found that there was no difference in humoral immunity between the 4-time inoculations at 7-day intervals and the 2-time inoculations at 28-day intervals. Intranasal IgA induced through the latter schedule with a smaller number of inoculations, which is clinically practical, exhibited cross-reactivity beyond the subtype of viral strains. In vitro toxicity studies demonstrated that the hyaluronic acid derivative was much less toxic than the corresponding PNVA-co-AA derivatives, and that both the polymers and their metabolites did not exhibit genotoxicity. Our results suggested that tetraglycine-L-octaarginine-linked hyaluronic acid would be a clinically valuable and safe adjuvant for mucosal vaccination.

Chitosan, alginate, hyaluronic acid, gums, and β-glucan as potent adjuvants and vaccine delivery systems for viral threats including SARS-CoV-2: A review

“…In-vitro examines showed low toxicity of the hyaluronic acid derivative compared to poly( N -vinylacetamide-co-acrylic acid) derivatives. Overall, this study confirmed the safety of hyaluronic acid-based adjuvant for mucosal influenza vaccination [ 41 ].…”

Evaluation of a _D-Octaarginine-linked polymer as a transfection tool for transient and stable transgene expression in human and murine cell lines

“…If stable-expression cells, which are established using VP-R8, are administered to the organism, and beneficial results are obtained, the application of VP-R8 to gene therapy in ex vivo methods wherein such highly stable expression efficiency is required will also be possible. The batch is identical to that used in the previous study [21].…”

“…c Mw of oligoarginine-linked polymers was calculated on the basis of Mw of PNVA-co-AA (350 kDa), Mw of oligoarginines, and the grafting degree. The batch is identical to that used in the previous study [ 21 ]. shows its physicochemical properties.…”

“…One production batch of VP-R8, which was reported in our previous study [21], was used in this study. Table 1 shows its physicochemical properties.…”

Cross-Protective Abilities of Hyaluronic Acid Modified with Tetraglycine-l-octaarginine as a Mucosal Adjuvant against Infection with Heterologous Influenza Viruses

“…The number of inoculations was successfully reduced to 2 times from 4 times through optimization of intervals between the first and the second inoculation, which boosts immune response through stimulation of immune memories acquired in the first inoculation, without any change of immune properties. 18 In the present study, heterologous virus challenge was performed to validate a potential of tetraglycine-L-octaarginine-linked hyaluronic acid as a mucosal adjuvant with crossprotective abilities.…”