Nanoparticle-Based Antigen Delivery: Advancing Immunization Strategies against Infectious Pathogens

Stimulation of adaptive immunity is a goal to defend against infectious agents. In recent years, vaccine development and improvements in their efficacy have been thoroughly investigated, and highly effective vaccines have been released to the market. The administration of vaccinations, safety, and the development of immunogenicity pose considerable challenges in this area. Investigations have been conducted on nanoparticle (NP)-based vaccines to address the issue. NPs are used in vaccine development to enhance antigen delivery, provide protection, and serve as adjuvants. The application of nanotechnology has substantially improved the delivery and effectiveness of vaccines by manipulating NP properties. Studies on NP-based immunizations have focused on viral pathogens and bacterial agents. Immunizations utilizing NPs enhance immune responses and stabilize viral antigens, facilitating the development of vaccines for hepatitis B, influenza, and HIV. Nanovaccines specifically target antigens associated with viruses, bacteria, and certain cancers. NP-based vaccines effectively stimulate and mature dendritic cells (DCs) in vitro and in vivo. Following vaccination, the NP-based vaccine resulted in increased cytokine levels and activated Th1 and Th2 cells in vivo. As a result, NP-based vaccines stimulate T-cell immune responses and adaptive immunity driven by immunoglobulin G and immunoglobulin M. This review has discussed the various NPs and antigens used in nanovaccine preparation; the role NPs play in activating adaptive immunity; and, specifically, the maturation of DCs; the activation of Th1 and Th2 cells against viruses, bacteria, and other microbial pathogens; and the safety of NPs.