Genetically Engineered Virus Nanofibers as an Efficient Vaccine for Preventing Fungal Infection

Bacteriophages: a potential game changer in food processing industry

In the food industry, despite the widespread use of interventions such as preservatives and thermal and non-thermal processing technologies to improve food safety, incidences of foodborne disease continue to happen worldwide, prompting the search for alternative strategies. Bacteriophages, commonly known as phages, have emerged as a promising alternative for controlling pathogenic bacteria in food. This review emphasizes the potential applications of phages in biological sciences, food processing, and preservation, with a particular focus on their role as biocontrol agents for improving food quality and preservation. By shedding light on recent developments and future possibilities, this review highlights the significance of phages in the food industry. Additionally, it addresses crucial aspects such as regulatory status and safety concerns surrounding the use of bacteriophages. The inclusion of up-to-date literature further underscores the relevance of phage-based strategies in reducing foodborne pathogenic bacteria's presence in both food and the production environment. As we look ahead, new phage products are likely to be targeted against emerging foodborne pathogens. This will further advance the efficacy of approaches that are based on phages in maintaining the safety and security of food.

Unraveling the potential of M13 phages in biomedicine: Advancing drug nanodelivery and gene therapy

M13 phages possessing filamentous phage genomes offer the benefits of selective display of molecular moieties and delivery of therapeutic agent payloads with a tolerable safety profile. M13 phage-displayed technology for resembling antigen portions led to the discovery of mimetic epitopes that applied to antibody-based therapy and could be useful in the design of anticancer vaccines. To date, the excremental experiences have engaged the M13 phage in the development of innovative biosensors for detecting biospecies, biomolecules, and human cells with an acceptable limit of detection. Addressing the emergence of antibiotic-resistant bacteria, M13 phages are potent for packaging the programmed gene editing tools, such as CRISPR/Cas, to target multiple antimicrobial genes. Moreover, their display potential in combination with nanoparticles inspires new approaches for engineering targeted theragnostic platforms targeting multiple cellular biomarkers in vivo. In this review, we present the available data on optimizing the use of bacteriophages with a focus on the to date experiences with M13 phages, either as monoagent or as part of combination regimens in the practices of biosensors, vaccines, bactericidal, modeling of specific antigen epitopes, and phage-guided nanoparticles for drug delivery systems. Despite increasing research interest, a deep understanding of the underlying biological and genetic behaviors of M13 phages is needed to enable the full potential of these bioagents in biomedicine, as discussed here. We also discuss some of the challenges that have thus far limited the development and practical marketing of M13 phages.

Homobifunctional imidoester-modified zinc nano-spindle attenuated hyphae growth of Aspergillus against hypersensitivity responses

Fungi cause various forms of invasive fungal disease (IFD), and fungal sensitization can contribute to the development of asthma, asthma severity, and other hypersensitivity diseases, such as atopic dermatitis (AD). In this study, we introduce a facile and controllable approach, using homobifunctional imidoester-modified zinc nano-spindle (HINS), for attenuating hyphae growth of fungi and reducing the hypersensitivity response complications in fungi-infected mice. To extend the study of the specificity and immune mechanisms, we used HINS-cultured Aspergillus extract (HI-AsE) and common agar-cultured Aspergillus extract (Con-AsE) as the refined mouse models. HINS composites within the safe concentration range inhibited the hyphae growth of fungi but also reduce the number of fungal pathogens. Through the evaluation of lung and skin tissues from the mice, asthma pathogenesis (lung) and the hypersensitivity response (skin) to invasive aspergillosis were least severe in HI-AsE-infected mice. Therefore, HINS composites attenuate asthma and the hypersensitivity response to invasive aspergillosis.

Phage nanoparticle as a carrier for controlling fungal infection

A mass of nanocarriers have been exploited and utilized for prevention of fungi, including organic nanomaterials, inorganic nanoparticles, polypeptides, and viruses. Due to biological safety and flexible genetic engineering property, bacteriophages, as bionanoparticles, are widely used in the diagnosis and treatment of microorganisms, which can be easily loaded with proteins and drugs. In particular, random DNAs can be inserted into the genome of phage by phage display technology, and it is possible to obtain the peptide/antibody targeting fungi from phage library. Meanwhile, phages displaying specific peptides are able to conjugate with other nanoparticles, which have both characteristics of peptides and nanomaterials, and have been used for precise detection of fungi. Additionally, phage nanomaterials as carriers can reduce the toxicity of drugs, increase the time of drug circulation, stimulate the immune response, and have an anti-fungal effect by itself. In this review, we summarize the recent applications of bacteriophages on the study of fungi. The improvement of our understanding of bacteriophage will supply new tools for controlling fungal infections. These phage libraries were used to pan the specific peptides for diagnosis, prevention, and treatment of fungi. KEY POINTS: • System fungal infection has no significant clinical symptoms; it is important to develop vaccine, diagnosis, and therapeutic agents to reduce mortality; phage is an ideal carrier for vaccine and drug to stimulate immune response and improve the efficiency of drug, and also can improve the sensitivity of detection • This review summarized recent studies on phage-based fungal vaccine and threw light on the developing therapeutic phage in the treatment of fungal infection.

The Role of B-Cells and Antibodies against Candida Vaccine Antigens in Invasive Candidiasis

Systemic candidiasis is an invasive fungal infection caused by members of the genus Candida. The recent emergence of antifungal drug resistance and increased incidences of infections caused by non-albicans Candida species merit the need for developing immune therapies against Candida infections. Although the role of cellular immune responses in anti-Candida immunity is well established, less is known about the role of humoral immunity against systemic candidiasis. This review summarizes currently available information on humoral immune responses induced by several promising Candida vaccine candidates, which have been identified in the past few decades. The protective antibody and B-cell responses generated by polysaccharide antigens such as mannan, β-glucan, and laminarin, as well as protein antigens like agglutinin-like sequence gene (Als3), secreted aspartyl proteinase (Sap2), heat shock protein (Hsp90), hyphally-regulated protein (Hyr1), hyphal wall protein (Hwp1), enolase (Eno), phospholipase (PLB), pyruvate kinase (Pk), fructose bisphosphate aldolase (Fba1), superoxide dismutase gene (Sod5) and malate dehydrogenase (Mdh1), are outlined. As per studies reviewed, antibodies induced in response to leading Candida vaccine candidates contribute to protection against systemic candidiasis by utilizing a variety of mechanisms such as opsonization, complement fixation, neutralization, biofilm inhibition, direct candidacidal activity, etc. The contributions of B-cells in controlling fungal infections are also discussed. Promising results using anti-Candida monoclonal antibodies for passive antibody therapy reinforces the need for developing antibody-based therapeutics including anti-idiotypic antibodies, single-chain variable fragments, peptide mimotopes, and antibody-derived peptides. Future research involving combinatorial immunotherapies using humanized monoclonal antibodies along with antifungal drugs/cytokines may prove beneficial for treating invasive fungal infections.

Phages in vaccine design and immunity; mechanisms and mysteries

Bacteriophages have attracted extensive interest in vaccine design. This includes the use of phage display technology to select antigens, the use of engineered phages displaying target antigens in vaccine formulations, and phage DNA vaccines. However, the development of these approaches is limited in part by uncertainty regarding the underlying mechanisms by which phages elicit immunity. This has stymied the clinical development of this technology. Here we review the immunology of phage vaccines and highlight the gaps in our knowledge regarding the underlying mechanisms. First, we review the basic biology of phages and their use in vaccines. Next we discuss what is known about the mechanisms of immunity against engineered phages and phage DNA. Finally, we highlight the gaps in our understanding regarding the immunogenicity of these preparations. We argue that mechanistic insight into the immunology of phage vaccines is essential for the further development and clinical utility of these technologies.

Phage nanofibers in nanomedicine: Biopanning for early diagnosis, targeted therapy, and proteomics analysis

Display of a peptide or protein of interest on the filamentous phage (also known as bacteriophage), a biological nanofiber, has opened a new route for disease diagnosis and therapy as well as proteomics. Earlier phage display was widely used in protein-protein or antigen-antibody studies. In recent years, its application in nanomedicine is becoming increasingly popular and encouraging. We aim to review the current status in this research direction. For better understanding, we start with a brief introduction of basic biology and structure of the filamentous phage. We present the principle of phage display and library construction method on the basis of the filamentous phage. We summarize the use of the phage displayed peptide library for selecting peptides with high affinity against cells or tissues. We then review the recent applications of the selected cell or tissue targeting peptides in developing new targeting probes and therapeutics to advance the early diagnosis and targeted therapy of different diseases in nanomedicine. We also discuss the integration of antibody phage display and modern proteomics in discovering new biomarkers or target proteins for disease diagnosis and therapy. Finally, we propose an outlook for further advancing the potential impact of phage display on future nanomedicine. This article is categorized under: Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.

Phage display as a tool for vaccine and immunotherapy development

Bacteriophages, or phages, are viruses that specifically infect bacteria and coopt the cellular machinery to create more phage proteins, eventually resulting in the release of new phage particles. Phages are heavily utilized in bioengineering for applications ranging from tissue engineering scaffolds to immune signal delivery. Of specific interest to vaccines and immunotherapies, phages have demonstrated an ability to activate both the innate and adaptive immune systems. The genome of these viral particles can be harnessed for DNA vaccination, or the surface proteins can be exploited for antigen display. More specifically, genes that encode an antigen of interest can be spliced into the phage genome, allowing antigenic proteins or peptides to be displayed by fusion to phage capsid proteins. Phages therefore present antigens to immune cells in a highly ordered and repetitive manner. This review discusses the use of phage with adjuvanting activity as antigen delivery vehicles for vaccination against infectious disease and cancer.

Enhancement of Photodynamic Cancer Therapy by Physical and Chemical Factors

The viable use of photodynamic therapy (PDT) in cancer therapy has never been fully realized because of its undesirable effects on healthy tissues. Herein we summarize some physicochemical factors that can make PDT a more viable and effective option to provide future oncological patients with better-quality treatment options. These physicochemical factors include light sources, photosensitizer (PS) carriers, microwaves, electric fields, magnetic fields, and ultrasound. This Review is meant to provide current information pertaining to PDT use, including a discussion of in vitro and in vivo studies. Emphasis is placed on the physicochemical factors and their potential benefits in overcoming the difficulty in transitioning PDT into the medical field. Many advanced techniques, such as employing X-rays as a light source, using nanoparticle-loaded stem cells and bacteriophage bio-nanowires as a photosensitizer carrier, as well as integration with immunotherapy, are among the future directions.

Phage-based vaccines

Bacteriophages, or more colloquially as phages, are viruses that possess the ability to infect and replicate with bacterial cells. They are assembled from two major types of biomolecules, the nucleic acids and the proteins, with the latter forming a capsid and the former being encapsulated. In the eukaryotic hosts, phages are inert particulate antigens and cannot trigger pathogenesis. In recent years, many studies have been explored about using phages as nanomedicine platforms for developing vaccines due to their unique biological characteristics. The whole phage particles can be used for vaccine design in the form of phage-displayed vaccines or phage DNA vaccines. Phage-displayed vaccines are the phages with peptide or protein antigens genetically displayed on their surfaces as well as those with antigens chemically conjugated or biologically bound on their surfaces. The phages can then deliver the immunogenic peptides or proteins to the target cells or tissues. Phage DNA vaccines are the eukaryotic promoter-driven vaccine genes inserted in the phage genomes, which are carried by phages to the target cells to generate antigens. The antigens, either as the immunogenic peptides or proteins displayed on the phages, or as the products expressed from the vaccine genes, can serve as vaccines to elicit immune responses for disease prevention and treatment. Both phage-displayed vaccines and phage DNA vaccines promise a brilliant future for developing vaccines. This review presents the recent advancements in the field of phage-based vaccines and their applications in both the prevention and treatment of various diseases. It also discusses the challenges and perspectives in moving this field forwards.

Bacteriophage T4 nanoparticles for vaccine delivery against infectious diseases

Subunit vaccines containing one or more target antigens from pathogenic organisms represent safer alternatives to whole pathogen vaccines. However, the antigens by themselves are not sufficiently immunogenic and require additives known as adjuvants to enhance immunogenicity and protective efficacy. Assembly of the antigens into virus-like nanoparticles (VLPs) is a better approach as it allows presentation of the epitopes in a more native context. The repetitive, symmetrical, and high density display of antigens on the VLPs mimic pathogen-associated molecular patterns seen on bacteria and viruses. The antigens, thus, might be better presented to stimulate host's innate as well as adaptive immune systems thereby eliciting both humoral and cellular immune responses. Bacteriophages such as phage T4 provide excellent platforms to generate the nanoparticle vaccines. The T4 capsid containing two non-essential outer proteins Soc and Hoc allow high density array of antigen epitopes in the form of peptides, domains, full-length proteins, or even multi-subunit complexes. Co-delivery of DNAs, targeting molecules, and/or molecular adjuvants provides additional advantages. Recent studies demonstrate that the phage T4 VLPs are highly immunogenic, do not need an adjuvant, and provide complete protection against bacterial and viral pathogens. Thus, phage T4 could potentially be developed as a "universal" VLP platform to design future multivalent vaccines against complex and emerging pathogens.

Phage vaccines displaying YGKDVKDLFDYAQE epitope induce protection against systemic candidiasis in mouse model

Candida albicans is a common commensal and opportunistic fungal pathogen in human, which poses threat to human health, especially in immunocompromised patients. Unfortunately, few effective prophylactic and therapeutic strategies were applied to clinic practice. Recently, the peptide YGKDVKDLFDYAQE from Fructose-bisphosphate aldolase 1 (Fba1), as a vaccine, was reported to induce protection effects against systemic candidiasis. Here, we displayed this epitope peptide on the coat proteins (pIII or pVIII) of filamentous phage, and investigated their protective effects against C. albicans infections. Mice were immunized with recombinant phages (designated as phage-3F and phage-8F) or protein (rFba1), then challenged with C. albicans yeast cells via lateral tail vein. Results demonstrated that the recombinant phages as well as rFba1 apparently induced humoral and cellular immune responses, reduced fungal burden and relieved kidney damage in infected mice and significantly improved their survival rates. Briefly, all these findings indicated that the recombinant phages displaying the epitope YGKDVKDLFDYAQE have the potential to be developed into a new vaccine against C. albicans infections.

Innovative Approaches to Improve Anti-Infective Vaccine Efficacy

Safe and efficacious vaccines are arguably the most successful medical interventions of all time. Yet the ongoing discovery of new pathogens, along with emergence of antibiotic-resistant pathogens and a burgeoning population at risk of such infections, imposes unprecedented public health challenges. To meet these challenges, innovative strategies to discover and develop new or improved anti-infective vaccines are necessary. These approaches must intersect the most meaningful insights into protective immunity and advanced technologies with capabilities to deliver immunogens for optimal immune protection. This goal is considered through several recent advances in host-pathogen relationships, conceptual strides in vaccinology, and emerging technologies. Given a clear and growing risk of pandemic disease should the threat of infection go unmet, developing vaccines that optimize protective immunity against high-priority and antibiotic-resistant pathogens represents an urgent and unifying imperative.

Virus-Derived Peptides for Clinical Applications

Novel affinity agents with high specificity are needed to make progress in disease diagnosis and therapy. Over the last several years, peptides have been considered to have fundamental benefits over other affinity agents, such as antibodies, due to their fast blood clearance, low immunogenicity, rapid tissue penetration, and reproducible chemical synthesis. These features make peptides ideal affinity agents for applications in disease diagnostics and therapeutics for a wide variety of afflictions. Virus-derived peptide techniques provide a rapid, robust, and high-throughput way to identify organism-targeting peptides with high affinity and selectivity. Here, we will review viral peptide display techniques, how these techniques have been utilized to select new organism-targeting peptides, and their numerous biomedical applications with an emphasis on targeted imaging, diagnosis, and therapeutic techniques. In the future, these virus-derived peptides may be used as common diagnosis and therapeutics tools in local clinics.

Phage-Enabled Nanomedicine: From Probes to Therapeutics in Precision Medicine

Both lytic and temperate bacteriophages (phages) can be applied in nanomedicine, in particular, as nanoprobes for precise disease diagnosis and nanotherapeutics for targeted disease treatment. Since phages are bacteria-specific viruses, they do not naturally infect eukaryotic cells and are not toxic to them. They can be genetically engineered to target nanoparticles, cells, tissues, and organs, and can also be modified with functional abiotic nanomaterials for disease diagnosis and treatment. This Review will summarize the current use of phage structures in many aspects of precision nanomedicine, including ultrasensitive biomarker detection, enhanced bioimaging for disease diagnosis, targeted drug and gene delivery, directed stem cell differentiation, accelerated tissue formation, effective vaccination, and nanotherapeutics for targeted disease treatment. We will also propose future directions in the area of phage-based nanomedicines, and discuss the state of phage-based clinical trials.

Identification of Novel Short BaTiO3-Binding/Nucleating Peptides for Phage-Templated in Situ Synthesis of BaTiO3 Polycrystalline Nanowires at Room Temperature

Ferroelectric materials, such as tetragonal barium titanate (BaTiO3), have been widely used in a variety of areas including bioimaging, biosensing, and high power switching devices. However, conventional methods for the synthesis of tetragonal phase BaTiO3 usually require toxic organic reagents and high temperature treatments, and are thus not environment-friendly and energy-efficient. Here, we took advantage of the phage display technique to develop a novel strategy for the synthesis of BaTiO3 nanowires. We identified a short BaTiO3-binding/nucleating peptide, CRGATPMSC (named RS), from a phage-displayed random peptide library by biopanning technique and then genetically fused the peptide to the major coat protein (pVIII) of filamentous M13 phages to form the pVIII-RS phages. We found that the resultant phages could not only bind with the presynthesized BaTiO3 crystals but also induce the nucleation of uniform tetragonal BaTiO3 nanocrystals at room temperature and without the use of toxic reagents to form one-dimensional polycrystalline BaTiO3 nanowires. This approach enables the green synthesis of BaTiO3 polycrystalline nanowires with potential applications in bioimaging and biosensing fields.

Design, challenge, and promise of stimuli-responsive nanoantibiotics

Over the past few years, there have been calls for novel antimicrobials to combat the rise of drug-resistant bacteria. While some promising new discoveries have met this call, it is not nearly enough. The major problem is that although these new promising antimicrobials serve as a short-term solution, they lack the potential to provide a long-term solution. The conventional method of creating new antibiotics relies heavily on the discovery of an antimicrobial compound from another microbe. This paradigm of development is flawed due to the fact that microbes can easily transfer a resistant mechanism if faced with an environmental pressure. Furthermore, there has been some evidence to indicate that the environment of the microbe can provide a hint as to their virulence. Because of this, the use of materials with antimicrobial properties has been garnering interest. Nanoantibiotics, (nAbts), provide a new way to circumvent the current paradigm of antimicrobial discovery and presents a novel mechanism of attack not found in microbes yet; which may lead to a longer-term solution against drug-resistance formation. This allows for environment-specific activation and efficacy of the nAbts but may also open up and create new design methods for various applications. These nAbts provide promise, but there is still ample work to be done in their development. This review looks at possible ways of improving and optimizing nAbts by making them stimuli-responsive, then consider the challenges ahead, and industrial applications.Graphical abstractA graphic detailing how the current paradigm of antibiotic discovery can be circumvented by the use of nanoantibiotics.

Novel nanoscale bacteriophage-based single-domain antibodies for the therapy of systemic infection caused by Candida albicans

Candida albicans (C. albicans) is an important human commensal and opportunistic fungal pathogen. Secreted aspartyl proteinases (Saps) are a major virulence trait of C. albicans, and among these proteases Sap2 has the highest expression levels. It is possible that antibodies against Sap2 could provide an antifungal effect. In this study, two phages displaying anti-rSap2 single chain variable fragments (scFvs) were screened from human single fold scFv libraries, and their potential therapeutic roles were evaluated using a murine model infected by C. albicans. The in vivo efficacies were assessed by mortality rates, fungal burden and histological examination. Overall survival rates were significantly increased while the colony counts and infectious foci were significantly decreased after treatment with the scFv-phages relative to the control groups. In order to investigate the immune response provoked by scFv-phages, three kinds of cytokines (Th1, Th2 and Th17 types) were measured and a clear immune response was observed. These findings suggest that anti-rSap2 scFv-phages have potential in the therapy of systemic infection caused by C. albicans.