Nanovaccine: an emerging strategy

ABSTRACT

Introduction

Vaccination is so far the most effective way of eradicating infections. Rapidly emerging drug resistance against infectious diseases and chemotherapy-related toxicities in cancer warrant immediate vaccine development to save mankind. Subunit vaccines alone, however, fail to elicit sufficiently strong and long-lasting protective immunity against deadly pathogens. Nanoparticle (NP)-based delivery vehicles like microemulsions, liposomes, virosomes, nanogels, micelles and dendrimers offer promising strategies to overcome limitations of traditional vaccine adjuvants. Nanovaccines can improve targeted delivery, antigen presentation, stimulation of body’s innate immunity, strong T cell response combined with safety to combat infectious diseases and cancers. Further, nanovaccines can be highly beneficial to generate effective immutherapeutic formulations against cancer.

Areas covered

This review summarizes the emerging nanoparticle strategies highlighting their success and challenges in preclinical and clinical trials in infectious diseases and cancer. It provides a concise overview of current nanoparticle-based vaccines, their adjuvant potential and their cellular delivery mechanisms.

Expert opinion

The nanovaccines (50–250 nm in size) are most efficient in terms of tissue targeting, prolonged circulation and preferential uptake by the professional APCs chiefly due to their small size. More rational designing, improved antigen loading, extensive functionalization and targeted delivery are some of the future goals of ideal nanovaccines.

KEYWORDS:

• Nanoparticle
• nanovaccine
• adjuvant
• infection
• cancer
• COVID-19

Article highlights

• Nanoparticles like dendrimers, liposomes, VLP, solid lipid etc. vesicles are rapidly emerging platforms for present and future vaccine development due to their biocompatiblility, antigen multivalency, controlled release and targeted co-delivery of antigen/adjuvant for sustained immunity associated with generation of durable CD8⁺ T cell memory.

• Having the major obstacles like antigenic variation, instability, manufacturing constraints, poor endocytosis, more efficient targeting of nanoparticle-associated antigen towards dendritic cells and macrophages is required for prophylactic success against complex pathogens and tumors.

• In the context of poor prognosis in various rapidly spreading malignancies, nanoparticle-based therapeutic cancer vaccines alone or in combination with CAR-T cells and immune checkpoint blockade forms a blooming field of cancer research.

• Clear understanding of passive uptake of nanovaccines by tumor cells as restricted by intratumoral barriers, along with precise regulation of tumor microenvironment and immune cells is warranted for future clinical translation of cancer immunotherapy.

• COVID-19 mRNA lipid nanoparticle-based vaccine is a recent breakthrough in nanoparticle research for controlling this pandemic, which will prioritize the rapid expansion of nanotechnology in future vaccine efforts.

• Although the available COVID-19 vaccines use parenteral route for antigen delivery, nanoparticle formulated vaccines hold a great potency for mucosal delivery against respiratory diseases, through rapid mucosal penetration in lungs for better efficacy and safety profile.

• In-depth preclinical safety and efficacy evaluations are the most important considerations before commercialization of emerging nanovaccine platforms for inducing desired immunity against infectious diseases and cancer.

Acknowledgments

We thank Dr. Arun Bandyopadhay, the Director, CSIR-IICB, India for supporting this work.

Declaration of interests

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.

Author contributions

Both the authors equally contributed to perception, direct and intellectual conceptualization of the work and approved the final manuscript for publication.

Additional information

Funding

This work was supported by the Council of Scientific and Industrial Research (CSIR) grant [No. BSC0114]. The work has been partly supported by UK Research and Innovation under the grant ‘A global Network for Neglected Tropical Diseases’ [No. MR/P027989/1].