Optimising the oil phases of aluminium hydrogel-stabilised emulsions for stable, safe and efficient vaccine adjuvant

Abstract

To increase antibody secretion and dose sparing, squalene-in-water aluminium hydrogel (alum)-stabilised emulsions (ASEs) have been developed, which offer increased surface areas and cellular interactions for higher antigen loading and enhanced immune responses. Nevertheless, the squalene (oil) in previous attempts suffered from limited oxidation resistance, thus, safety and stability were compromised. From a clinical translational perspective, it is imperative to screen the optimal oils for enhanced emulsion adjuvants. Here, because of the varying oleic to linoleic acid ratio, soybean oil, peanut oil, and olive oil were utilised as oil phases in the preparation of aluminium hydrogel-stabilised squalene-in-water emulsions, which were then screened for their stability and immunogenicity. Additionally, the underlying mechanisms of oil phases and emulsion stability were unravelled, which showed that a higher oleic to linoleic acid ratio increased anti-oxidative capabilities but reduced the long-term storage stability owing to the relatively low zeta potential of the prepared droplets. As a result, compared with squalene-in-water ASEs, soybean-in-water ASEs exhibited comparable immune responses and enhanced stability. By optimising the oil phase of the emulsion adjuvants, this work may offer an alternative strategy for safe, stable, and effective emulsion adjuvants.

Graphical abstract

Keywords

pickering emulsion / vaccine adjuvant / alum-stabilised emulsion / oleic to linoleic acid ratio / stability

References

[1] Bosch F X, Robles C, Díaz M, Arbyn M, Baussano I, Clavel C, Ronco G, Dillner J, Lehtinen M, Petry K U, . HPV-Faster: broadening the scope for prevention of HPV-related cancer. Nature Reviews. Clinical Oncology, 2016, 13(2): 119–132

[2] Zhao H, Zhou X Y, Zhou Y H. Hepatitis B vaccine development and implementation. Human Vaccines & Immunotherapeutics, 2020, 16(7): 1533–1544

[3] Zeng Z, Cheng L, Chen X. Progress in research on polio vaccine. Chinese Journal of Biologicals, 2019, 32(6): 713–716, 720 (in Chinese)

[4] Bellini C, Horvati K. Recent advances in the development of protein-and peptide-based subunit vaccines against tuberculosis. Cells, 2020, 9(12): 2673

[5] Cossette B, Kelly S H, Collier J H. Intranasal subunit vaccination strategies employing nanomaterials and biomaterials. ACS Biomaterials Science & Engineering, 2021, 7(5): 1765–1779

[6] Do Tien D, Kim H, Jeong J, Park K H, Yang S, Oh T, Kim S, Kang I, Chae C. Comparative evaluation of the efficacy of commercial and prototype PRRS subunit vaccines against an HP-PRRSV challenge. Journal of Veterinary Medical Science, 2018, 80(9): 1463–1467

[7] Nevagi R J, Skwarczynski M, Toth I. Polymers for subunit vaccine delivery. European Polymer Journal, 2019, 114: 397–410

[8] Chao L, Xu L, Song G, Zhuang L. Emerging nanomedicine approaches fighting tumor metastasis: animal models, metastasis-targeted drug delivery, phototherapy, and immunotherapy. Chemical Society Reviews, 2016, 45(22): 6250–6269

[9] Dupuis M, Denis-Mize K, Labarbara A, Peters W, Charo I, Mcdonald D, Ott G. Immunization with the adjuvant MF59 induces macrophage trafficking and apoptosis. European Journal of Immunology, 2015, 31(10): 2910–2918

[10] Bui C, Bethmont A, Chughtai A, Gardner L, Sarkar S, Hassan S, Seale H, Macintyre C R. A systematic review of the comparative epidemiology of avian and human influenza A H5N1 and H7N9—essons and unanswered questions. Transboundary and Emerging Diseases, 2016, 63(6): 602–620

[11] Shah R R, Taccone M, Monaci E, Brito L A, Bonci A, O’Hagan D T, Amiji M M, Seubert A. The droplet size of emulsion adjuvants has significant impact on their potency, due to differences in immune cell-recruitment and-activation. Scientific Reports, 2019, 9(1): 11520

[12] Singh Y, Meher J G, Raval K, Khan F A, Chaurasia M, Jain N K, Chourasia M K. Nanoemulsion: concepts, development and applications in drug delivery. Journal of Controlled Release, 2017, 252: 28–49

[13] Xia Y, Wu J, Du Y, Miao C, Ma G. Bridging systemic immunity with gastrointestinal immune responses via oil-in-polymer capsules. Advanced Materials, 2018, 30(31): 1801067

[14] Peng S, Cao F, Xia Y, Gao X, Dai L, Yan J, Ma G. COVID-19 vaccines: particulate alum via Pickering emulsion for an enhanced COVID-19 vaccine adjuvant. Advanced Materials, 2020, 32(40): e2004210

[15] Song T, Xia Y, Du Y, Chen M W, Qing H, Ma G. Engineering the deformability of albumin-stabilized emulsions for lymph-node vaccine delivery. Advanced Materials, 2021, 33(26): e2100106

[16] Xia Y, Jie W, Wei W, Du Y, Tao W, Ma X, An W, Guo A, Miao C, Hua Y. Exploiting the pliability and lateral mobility of Pickering emulsion for enhanced vaccination. Nature Materials, 2018, 17(2): 187–194

[17] Shimizu N, Ito J, Kato S, Eitsuka T, Nakagawa K. Significance of squalene in rice bran oil and perspectives on aqualene oxidation. Journal of Nutritional Science and Vitaminology, 2019, 65(Suppl.): S62–S66

[18] Larsson K, Istenic K, Wulff T, Jonsdottir R, Kristinsson H, Freysdottir J, Undeland I, Jamnik P. Effect of in vitro digested cod liver oil of different quality on oxidative, proteomic and inflammatory responses in the yeast Saccharomyces cerevisiae and human monocyte-derived dendritic cells. Journal of the Science of Food and Agriculture, 2015, 95(15): 3096–3106

[19] Castelli G, Bianco I D, Kiyomi Mizutamari R. Polyphenol content in argentinean commercial extra virgin olive oil. European Journal of Lipid Science and Technology, 2018, 120(12): 1800124

[20] Li Q, Tang X, Lu S, Wu J. Composition and tocopherol, fatty acid, and phytosterol contents in micro-endosperm ultra-high oil corn. Grasas y Aceites, 2019, 70(3): e311

[21] Zhang T, Wang T, Liu R, Chang M, Jin Q, Wang X. Chemical characterization of fourteen kinds of novel edible oils: a comparative study using chemometrics. LWT, 2020, 118: 108725

[22] Combs R, Bilyeu K. Novel alleles of FAD2-1A induce high levels of oleic acid in soybean oil. Molecular Breeding, 2019, 39(6): 79–90

[23] Davis J P, Price K, Dean L L, Sweigart D S, Cottonaro J, Sanders T H. Peanut oil stability and physical properties across a range of industrially relevant oleic acid/linoleic acid ratios. Peanut Science, 2016, 43(1): PS14–17.1

[24] Gnoni A, Longo S, Damiano F, Gnoni G V, Giudetti A M. Oleic acid and olive oil polyphenols downregulate fatty acid and cholesterol synthesis in brain and liver cells. In: Olives and Olive Oil in Health and Disease Prevention. London: Elsevier, 2021, 651–657

[25] Cooper J F, Weary C E, Jordan F T. The impact of non-endotoxin LAL-reactive materials on Limulus amebocyte lysate analyses. PDA Journal of Pharmaceutical Science and Technology, 1997, 51(1): 2–6

[26] Symoniuk E, Ratusz K, Krygier K. Oxidative stability and the chemical composition of market cold-pressed linseed oil. European Journal of Lipid Science and Technology, 2017, 119(11): 1700055

[27] Siegler A J, Wiatrek S, Mouhanna F, Amico K R, Dominguez K, Jones J, Patel R R, Mena L A, Mayer K H. Validation of the HIV pre-exposure prophylaxis stigma scale: performance of Likert and semantic differential scale versions. AIDS and Behavior, 2020, 24(9): 2637–2649

[28] Fan B, Fenton O, Daly K, Ding J, Chen Q, Chen Q. Alum split applications strengthened phosphorus fixation and phosphate sorption in high legacy phosphorus calcareous soil. Journal of Enviromental Sciences, 2021, 101: 87–97

[29] Tan H, Han L, Yang C. Effect of oil type and β-carotene incorporation on the properties of gelatin nanoparticle-stabilized pickering emulsions. LWT, 2021, 141: 110903

[30] Yao X X, Liu Z, Ma M Z, Chao Y C, Gao Y X, Kong T T. Control of particle adsorption for stability of Pickering emulsions in microfluidics. Small, 2018, 14(37): e1802902

[31] Ghimire T R, Benson R A, Garside P, Brewer J M. Alum increases antigen uptake, reduces antigen degradation and sustains antigen presentation by DCs in vitro. Immunology Letters, 2012, 147(1-2): 55–62

[32] Carrillo J, Izquierdo-Useros N, Vila-Nieto C, Pradenas E, Blanco J. Humoral immune responses and neutralizing antibodies against SARS-CoV-2: implications in pathogenesis and protective immunity. Biochemical and Biophysical Research Communications, 2021, 538: 187–191

[33] Lin J Z, Xu R, Tian X H. Threshold dynamics of an HIV-1 model with both viral and cellular infections, cell-mediated and humoral immune responses. Mathematical Biosciences and Engineering, 2019, 16(1): 292–319

[34] Jalkanen S, Salmi M. Lymphatic endothelial cells of the lymph node. Nature Reviews. Immunology, 2020, 20(9): 566–578

[35] Koksel Y, Gencturk M, Spano A, Reynolds M, Roshan S, Caycı Z. Utility of Likert scale (Deauville criteria) in assessment of chemoradiotherapy response of primary oropharyngeal squamous cell cancer site. Clinical Imaging, 2019, 55: 89–94

[36] Krzych L J, Lach M, Joniec M, Cisowski M, Bochenek A. The Likert scale is a powerful tool for quality of life assessment among patients after minimally invasive coronary surgery. Kardiochir Torakochirurgia Pol, 2018, 15(2): 130–134

RIGHTS & PERMISSIONS

Higher Education Press