Enhancing Antibody Response against Small Molecular Hapten with Tobacco Mosaic Virus as a Polyvalent Carrier

Photothermal immunotherapy of melanoma using TLR-7 agonist laden tobacco mosaic virus with polydopamine coat

Photothermal therapy (PTT) is a promising cancer treatment that debulks tumors locally while priming immune responses. However, PTT as a standalone treatment approach often has limited systemic efficacy, motivating the development of synergistic combination approaches. Toward this goal, herein, the tobacco mosaic virus (TMV) was loaded with a small molecule immunomodulator, toll-like receptor 7 agonist (1V209), and its surface was coated with photothermal biopolymer polydopamine (PDA). The resulting 1V209-laden and PDA-coated TMV was used to treat B16F10 dermal melanoma in C57BL/6 mice. 1V209-TMV-PDA was intratumorally injected and irradiated using an 808-nm near infrared laser. 60 % of the mice receiving PTT with intratumoral 1V209-TMV-PDA + laser remained alive at the end point - in contrast to only 20 % survivors were observed in the control group. Immunological analysis indicates systemic anti-tumor immunity being induced by the combination therapy with a greater number of tumor-specific T cells (as determined by a splenocyte assay). This study highlights the potential of TMV versatility as a multifunctional nano-platform for combined PTT-immunotherapy.

Application of built-in adjuvants for epitope-based vaccines

Several studies have shown that epitope vaccines exhibit substantial advantages over conventional vaccines. However, epitope vaccines are associated with limited immunity, which can be overcome by conjugating antigenic epitopes with built-in adjuvants (e.g., some carrier proteins or new biomaterials) with special properties, including immunologic specificity, good biosecurity and biocompatibility, and the ability to vastly improve the immune response of epitope vaccines. When designing epitope vaccines, the following types of built-in adjuvants are typically considered: (1) pattern recognition receptor ligands (i.e., toll-like receptors); (2) virus-like particle carrier platforms; (3) bacterial toxin proteins; and (4) novel potential delivery systems (e.g., self-assembled peptide nanoparticles, lipid core peptides, and polymeric or inorganic nanoparticles). This review primarily discusses the current and prospective applications of these built-in adjuvants (i.e., biological carriers) to provide some references for the future design of epitope-based vaccines.

Evaluation of Three Morphologically Distinct Virus-Like Particles as Nanocarriers for Convection-Enhanced Drug Delivery to Glioblastoma

Glioblastoma is a particularly challenging cancer, as there are currently limited options for treatment. New delivery routes are being explored, including direct intratumoral injection via convection-enhanced delivery (CED). While promising, convection-enhanced delivery of traditional chemotherapeutics such as doxorubicin (DOX) has seen limited success. Several studies have demonstrated that attaching a drug to polymeric nanoscale materials can improve drug delivery efficacy via CED. We therefore set out to evaluate a panel of morphologically distinct protein nanoparticles for their potential as CED drug delivery vehicles for glioblastoma treatment. The panel consisted of three different virus-like particles (VLPs), MS2 spheres, tobacco mosaic virus (TMV) disks and nanophage filamentous rods modified with DOX. While all three VLPs displayed adequate drug delivery and cell uptake in vitro, increased survival rates were only observed for glioma-bearing mice that were treated via CED with TMV disks and MS2 spheres conjugated to doxorubicin, with TMV-treated mice showing the best response. Importantly, these improved survival rates were observed after only a single VLP–DOX CED injection several orders of magnitude smaller than traditional IV doses. Overall, this study underscores the potential of nanoscale chemotherapeutic CED using virus-like particles and illustrates the need for further studies into how the overall morphology of VLPs influences their drug delivery properties.

Synthetic plant virology for nanobiotechnology and nanomedicine

Nanotechnology is a rapidly expanding field seeking to utilize nano-scale structures for a wide range of applications. Biologically derived nanostructures, such as viruses and virus-like particles (VLPs), provide excellent platforms for functionalization due to their physical and chemical properties. Plant viruses, and VLPs derived from them, have been used extensively in biotechnology. They have been characterized in detail over several decades and have desirable properties including high yields, robustness, and ease of purification. Through modifications to viral surfaces, either interior or exterior, plant-virus-derived nanoparticles have been shown to support a range of functions of potential interest to medicine and nano-technology. In this review we highlight recent and influential achievements in the use of plant virus particles as vehicles for diverse functions: from delivery of anticancer compounds, to targeted bioimaging, vaccine production to nanowire formation. WIREs Nanomed Nanobiotechnol 2017, 9:e1447. doi: 10.1002/wnan.1447 For further resources related to this article, please visit the WIREs website.

Stable Disk Assemblies of a Tobacco Mosaic Virus Mutant as Nanoscale Scaffolds for Applications in Drug Delivery

Current approaches to nanoscale therapeutic delivery rely on the attachment of a drug of interest to a nanomaterial scaffold that is capable of releasing the drug selectively in a tumor environment. One class of nanocarriers receiving significant attention is protein nanomaterials, which are biodegradable and homogeneous in morphology and can be equipped with multiple functional handles for drug attachment. Although most protein-based nanocarriers are spherical in morphology, recent research has revealed that nonspherical nanomaterials may have favorable tumor uptake in comparison to their spherical counterparts. It is therefore important to expand the number of nonspherical protein-based nanocarriers that are available. Herein, we report the development of a self-assembling nanoscale disk derived from a double arginine mutant of recombinantly expressed tobacco mosaic virus coat protein (RR-TMV). RR-TMV disks display highly stable double-disk assembly states. These RR-TMV disks were functionalized with the chemotherapy drug doxorubicin (DOX) and further modified with polyethylene glycol (PEG) for improved solubility. RR-TMV_DOX-PEG displayed cytotoxic properties similar to those of DOX alone when incubated with U87MG glioblastoma cells, but unmodified RR-TMV did not cause any cytotoxicity. The RR-TMV disk assembly represents a promising protein-based nanomaterial for applications in drug delivery.