Carbohydrate-containing nanoparticles as vaccine adjuvants

ABSTRACT

Introduction: Adjuvants are essential to vaccines for immunopotentiation in the elicitation of protective immunity. However, classical and widely used aluminum-based adjuvants have limited capacity to induce cellular response. There are increasing needs for appropriate adjuvants with improved profiles for vaccine development toward emerging pathogens. Carbohydrate-containing nanoparticles (NPs) with immunomodulatory activity and particulate nanocarriers for effective antigen presentation are capable of eliciting a more balanced humoral and cellular immune response.

Areas covered: We reviewed several carbohydrates with immunomodulatory properties. They include chitosan, β-glucan, mannan, and saponins, which have been used in vaccine formulations. The mode of action, the preparation methods, characterization of these carbohydrate-containing NPs and the corresponding vaccines are presented.

Expert opinion: Several carbohydrate-containing NPs have entered the clinical stage or have been used in licensed vaccines for human use. Saponin-containing NPs are being evaluated in a vaccine against SARS-CoV-2, the pathogen causing the on-going worldwide pandemic. Vaccines with carbohydrate-containing NPs are in different stages of development, from preclinical studies to late-stage clinical trials. A better understanding of the mode of action for carbohydrate-containing NPs as vaccine carriers and as immunostimulators will likely contribute to the design and development of new generation vaccines against cancer and infectious diseases.

KEYWORDS:

• Antigen presentation
• carbohydrate
• immune potentiation
• mechanism
• nanoparticle
• vaccine adjuvant

Article highlights

• Novel adjuvants with improved properties could boost the immune response of non-virus-like particle antigens.

• Carbohydrate-containing nanoparticles help facilitate antigen delivery and elicit a desirable immune response.

• Cationic polysaccharide chitosan-containing NPs are capable of eliciting a balanced cellular and humoral immune response.

• β-glucan and mannan could act as motif-targeting molecules to achieve targeted delivery.

• Saponin-containing NPs can elicit robust cellular response and have been used in licensed human vaccines. The evaluation of vaccines against COVID-19 is on-going in late-stage clinical trials.

Author contributions

Qinjian Zhao contributed to the conceptualization and Funding acquisition of this manuscript. Xinyuan Zhang wrote and edited this manuscript. Zhigang Zhang edited this manuscript. Ningshao Xia contributed to the Funding acquisition of this manuscript.

Declarations of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Declaration of interest

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by National Natural Science Foundation of China [32070925].