PEG Spacer Length Substantially Affects Antibody-Based Nanocarrier Targeting of Dendritic Cell Subsets

Nanobodies Outperform Antibodies - Rapid Functionalization with Equal In Vivo Targeting Properties

Highly specific targeting of dendritic cells in vivo is crucial for the development of effective tumor nanovaccines. This group recently presented an antibody-functionalized nanocarrier system able to maintain its targeting properties when transferred from in vitro to in vivo studies. However, producing this system requires long synthesis times and involves high expenses due to the involved site-specific enzymatic multi-step modification procedure of the antibody. Consequently, improving the previously proposed system is necessary in order to accelerate the development. Here, a novel system utilizing nanobodies for the targeting of dendritic cells is presented. A C-terminal cysteine tag facilitates an easy attachment of the nanobody to the nanocarrier via a thiol-maleimide conjugation technique. This reduces the functionalization time from several days to mere hours. Using in vitro and in vivo assays, it is shown that the optimized system possesses equal targeting properties as the antibody-based system. As a result, nanobodies and the coupling chemistry are found to be a superior strategy for the in vivo targeting of dendritic cells when compared to antibodies, due to their rapid attachment to nanocarriers and equal targeting specificity. This would replace antibodies as the current "gold standard" of targeting moieties.

The Application of Nanovaccines in Autoimmune Diseases

Autoimmune diseases are diseases caused by the body's chronic immune responses to self-antigens and attacks on the host's own cells, tissues and organs. The dysfunction of innate immunity and adaptive immunity leads to the destruction of autoimmune tolerance, which is the most basic factor leading to pathogenesis. The optimal strategy for autoimmune diseases is to modify the host immune system to restore tolerance. The ideal effect of therapeutic autoimmune diseases is to eliminate the autoantigen-specific spontaneous immune response without interfering with the immune response against other antigens. Therapeutic nanovaccines that produce immune tolerance conform to this principle. Nanomaterials provide a platform for antigen loading and modification due to their unique physical and chemical properties. Nanovaccines based on nanomaterial technology can simultaneously enable antigens and adjuvants to be absorbed by immune cells and induce rapid and durable immunity. Nanovaccines have the advantages of being able to be designed and loaded and of better protecting antigens from premature degradation. Nanovaccines also have the ability to target specific tissues or cells through optimized design. We review the latest research progress of nanovaccines for autoimmune diseases and the design strategies of nanovaccines to promote the development of more effective nanovaccines for autoimmune diseases.