Figure 1.

Overview of the mechanisms by which nanovaccines can induce an immune response. (A) Nanoparticles can be used as a vaccine platform for several infectious diseases since they can deliver antigens and several immunostimulatory molecules (TLR ligands and adjuvants). The antigen could be encapsulated, adsorbed, and dispersed on the nanoparticle matrix. The immunostimulatory activity of nanovaccines is related to several mechanisms, such as the depot effect, gradual release of vaccine antigens, and recruitment of antigen-presenting cells. (B) Smaller nanoparticles (<25 nm) are transported through the lymphatic system more quickly than larger particles (>100 nm). Smaller nanoparticles could accumulate in dendritic cells (DC) resident in the lymph nodes. These resident DC can process and present the antigen to T cells on the lymph node. In contrast, larger nanoparticles are efficiently uptake by APCs present or recruited on the injection site. These APCs can also process the antigen and migrate to the lymph node to present the T cells’ antigen.Legend: APC: antigen-presenting cell; DC: dendritic cells; TLR: toll-like receptor.