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3 Ferritin nanoparticles used in vaccine development -- Nanotechnology increasingly plays a significant role in vaccine development in the past decade, leading to the birth of “nanovaccinology” [47]. The use of nanoparticles in vaccine formulations is expected to have improved antigen stability and immunogenicity, targeted delivery and slow release property [48–50]. There have been many types of nanoparticle used in the field of vaccine development [51], including polymeric nanoparticles [52–54], inorganic nanoparticles [55,56], liposomes [57], virus-like particles [58,59], self-assembled proteins [60], etc. Ferritin, with its particle uniformity and inner/outer surface modifiable features, can play an important role in the field of vaccine development.

Kanekiyo et al. [61] used Helicobacter pylori non-haem ferritin [62] to develop a vaccine which can elicit broadly neutralizing H1N1 antibodies. Haemagglutinin of influenza virus was inserted at the interface of adjacent subunits so that eight trimeric viral spikes are formed on the surface of ferritin nanoparticle during the spontaneous assembly process. Immunization with this influenza-ferritin nano-particle vaccine produced haemagglutination inhibition antibody titers of one magnitude higher than those from the licensed inactivated vaccine.

Dendritic cells (DCs) are the most potent professional antigen-presenting cells that initiate and control antigen-specific immune responses. DCs plays an important role in internalizing, processing, and presenting antigens to naive T cells and inducing their proliferation and differentiation into effector cells, such as CD8+ cytotoxic T cells to kill infected target cells or CD4+ helper T cells to secrete cytokines and facilitate diverse forms of cellular and humoral immunity [63]. DC-based vaccine development has been a promising approach to direct antigen-specific adaptive immunity in vivo [64,65]. Han et al. [66] used ferritin nanoparticles to display different ovalbumin antigens. The ovalbumin antigenic peptides OT-1 (Oval-bumin257–264) [67] and OT-2 (Ovalbumin323–339) [67] were genetically introduced either onto the exterior surface or into the interior cavity of ferritin, and the nanoparticles were effectively delivered to DCs and processed within endosomes, followed by successful induction of antigen-specific CD8+ or CD4+ T cells. On the other hand, this ferritin-OT nanoparticle immune effect was also confirmed on mice. Immunized with ferritin-OT1 peptides efficiently differentiated OT-1 specific CD8+ T cells into functional effector cytotoxic T cells, resulting in selective killing of antigen-specific target cells. Immunized with ferritin-OT2 peptides resulted in the differentiation of proliferated OT-2 specific CD4+ T cells into functional CD4+ Th1 and Th2 cells which was confirmed by the detection of the cell-produced IFN-γ/IL-2 and IL-10/IL-13 cytokines.

Additional article follows;

https://www.mdpi.com/1422-0067/20/10/2426/htm

Ferritin is a spherical iron storage protein composed of 24 subunits and an iron core. Using biomimetic mineralization, magnetic iron oxide can be synthesized in the cavity of ferritin to form magnetoferritin (MFt). MFt, also known as a superparamagnetic protein, is a novel magnetic nanomaterial with good biocompatibility and flexibility for biomedical applications. Recently, it has been demonstrated that MFt had tumor targetability and a peroxidase-like catalytic activity. Thus, MFt, with its many unique properties, provides a powerful platform for tumor diagnosis and therapy. In this review, we discuss the biomimetic synthesis and biomedical applications of MFt.

4. Biomedical Applications -- MFt has been widely applied in the biomedical field due to its unique properties, including tissue imaging, drug delivery, and medical diagnosis [1]. Artificial MFt has also been used as a model system of pathological ferritin to investigate the corresponding underlying biological mechanism involved [19]. Recently, MFt containing an iron oxide core achieved many advances in biomedical applications, and an additional modification has greatly expanded the field (Table 1).

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In addition to applications, such as tumor imaging and diagnosis, MFt could also be used for tumor therapy as a nanocarrier.