Selective APC-targeting of a novel Fc-fusion multi-immunodominant recombinant protein (tTax-tEnv:mFcγ2a) for HTLV-1 vaccine development

Tailoring biomaterials for vaccine delivery

Biomaterials are substances that can be injected, implanted, or applied to the surface of tissues in biomedical applications and have the ability to interact with biological systems to initiate therapeutic responses. Biomaterial-based vaccine delivery systems possess robust packaging capabilities, enabling sustained and localized drug release at the target site. Throughout the vaccine delivery process, they can contribute to protecting, stabilizing, and guiding the immunogen while also serving as adjuvants to enhance vaccine efficacy. In this article, we provide a comprehensive review of the contributions of biomaterials to the advancement of vaccine development. We begin by categorizing biomaterial types and properties, detailing their reprocessing strategies, and exploring several common delivery systems, such as polymeric nanoparticles, lipid nanoparticles, hydrogels, and microneedles. Additionally, we investigated how the physicochemical properties and delivery routes of biomaterials influence immune responses. Notably, we delve into the design considerations of biomaterials as vaccine adjuvants, showcasing their application in vaccine development for cancer, acquired immunodeficiency syndrome, influenza, corona virus disease 2019 (COVID-19), tuberculosis, malaria, and hepatitis B. Throughout this review, we highlight successful instances where biomaterials have enhanced vaccine efficacy and discuss the limitations and future directions of biomaterials in vaccine delivery and immunotherapy. This review aims to offer researchers a comprehensive understanding of the application of biomaterials in vaccine development and stimulate further progress in related fields.

HTLV-1 vaccination Landscape: Current developments and challenges

Human T-lymphotropic virus type 1 (HTLV-1) is a retrovirus that is distinguished for its correlation to myelopathy/tropical spastic paraparesis (HAM/TSP) and adult T-cell leukemia/lymphoma (ATLL). As well, HTLV-1 has been documented to have links with other inflammatory diseases, such as uveitis and dermatitis. According to the World Health Organization (WHO), the global distribution of HTLV-1 infection is estimated to extend between 5 and 10 million individuals. Recent efforts in HTLV-1 vaccine development primarily involve selecting viral components, such as antigens, from structural and non-structural proteins. These components are chosen to trigger a vigorous immune response from cytotoxic T lymphocytes (CTLs), helper T lymphocytes (HTLs), and B cells. Investigation into developing a vaccine against HTLV-1 is ongoing, and current surveys have explored several approaches, including viral vector vaccines, DNA vaccines, protein and peptide vaccines, dendritic cell-based vaccines, mRNA vaccines, and other platforms. Despite these investigations have shown promising results, challenges like the necessity for long-term protective immunity, addressing viral diversity, and managing potential side effects remain. It is critical to keep track of the progress made in HTLV-1 vaccination research to comprehend the development status and its possible impacts. The evolving nature of vaccine development underscores the importance of staying informed about advancements as we strive to combat HTLV-1-associated diseases through effective vaccination strategies. In this review, our goal is to provide an overview of the current status of HTLV-1 vaccination efforts, emphasizing the progress, challenges, and potential future directions in this vital area of research.

Novel insights into human T-lymphotropic virus type-1 (HTLV-1) pathogenesis-host interactions in the manifestation of HTLV-1-associated myelopathy/tropical spastic paraparesis

Human T-lymphotropic virus type-1 (HTLV-1) was the first discovered human oncogenic retrovirus, the etiological agent of two serious diseases have been identified as adult T-cell leukaemia/lymphoma malignancy and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), a debilitating chronic neuro-myelopathy. Despite more than 40 years of molecular, histopathological and immunological studies on HTLV-1-associated diseases, the virulence and pathogenicity of this virus are yet to be clarified. The reason why the majority of HTLV-1-infected individuals (∼95%) remain asymptomatic carriers is still unclear. The deterioration of the immune system towards oncogenicity and autoimmunity makes HTLV-1 a natural probe for the study of malignancy and neuro-inflammatory diseases. Additionally, its slow worldwide spreading has prompted public health authorities and researchers, as urged by the WHO, to focus on eradicating HTLV-1. In contrast, neither an effective therapy nor a protective vaccine has been introduced. This comprehensive review focused on the most relevant studies of the neuro-inflammatory propensity of HTLV-1-induced HAM/TSP. Such an emphasis on the virus-host interactions in the HAM/TSP pathogenesis will be critically discussed epigenetically. The findings may shed light on future research venues in designing and developing proper HTLV-1 therapeutics.

Adjuvants for cancer mRNA vaccines in the era of nanotechnology: strategies, applications, and future directions

Research into mRNA vaccines is advancing rapidly, with proven efficacy against coronavirus disease 2019 and promising therapeutic potential against a variety of solid tumors. Adjuvants, critical components of mRNA vaccines, significantly enhance vaccine effectiveness and are integral to numerous mRNA vaccine formulations. However, the development and selection of adjuvant platforms are still in their nascent stages, and the mechanisms of many adjuvants remain poorly understood. Additionally, the immunostimulatory capabilities of certain novel drug delivery systems (DDS) challenge the traditional definition of adjuvants, suggesting that a revision of this concept is necessary. This review offers a comprehensive exploration of the mechanisms and applications of adjuvants and self-adjuvant DDS. It thoroughly addresses existing issues mentioned above and details three main challenges of immune-related adverse event, unclear mechanisms, and unsatisfactory outcomes in old age group in the design and practical application of cancer mRNA vaccine adjuvants. Ultimately, this review proposes three optimization strategies which consists of exploring the mechanisms of adjuvant, optimizing DDS, and improving route of administration to improve effectiveness and application of adjuvants and self-adjuvant DDS.

Momordica charantia phytoconstituents can inhibit human T-lymphotropic virus type-1 (HTLV-1) infectivity in vitro and in vivo

There is an urgent need to find an effective therapy for life-threatening HTLV-1-associated diseases. Bitter melon (Momordica charantia) is considered a traditional herb with antiviral and anticancer properties and was tested in this study on HTLV-1 infectivity. GC-MS analyzed the alcoholic extract. In vitro assay was carried out using transfection of HUVEC cells by HTLV-1-MT2 cell line. The cells were exposed to alcoholic and aqueous extracts at 5,10, and 20 µg/mL concentrations. In vivo, mice were divided into four groups. Three groups were treated with HTLV-1-MT-2 cells as test groups and positive control, and PBS as the negative control group in the presence and absence of M. charantia extracts. Peripheral blood mononuclear cells (PBMCs), mesenteric lymph nodes (MLNs), and splenocytes were collected for HTLV-1-proviral load (PVL) assessment, TaqMan-qPCR. The GC-MS analysis revealed 36 components in M. charantia. The studies showed significant reductions in HTLV-1-PVL in the presence of extract in the HUVEC-treated groups (P = 0.001). Furthermore, the inhibitory effects of extracts on HTLV-1 infected mice showed significant differences in HTLV-1-PVL among M. charantia treated groups with untreated (P = 0.001). The T-cells in MLNs were significantly more susceptible to HTLV-1 than others (P = 0.001). There were significant differences among HTLV-1-infected cells in MLNs and splenocytes (P = 0.001 and 0.046, respectively). Also, aqueous and alcoholic extract-treated groups significantly affected HTLV-1-infected PBMCs (P = 0.002 and 0.009, respectively). M. charantia may have effective antiviral properties. The substantial compound of M. charantia could have inhibitory effects on the proliferation and transmission of HTLV-1 oncovirus.

Vaccine adjuvants: mechanisms and platforms

Adjuvants are indispensable components of vaccines. Despite being widely used in vaccines, their action mechanisms are not yet clear. With a greater understanding of the mechanisms by which the innate immune response controls the antigen-specific response, the adjuvants' action mechanisms are beginning to be elucidated. Adjuvants can be categorized as immunostimulants and delivery systems. Immunostimulants are danger signal molecules that lead to the maturation and activation of antigen-presenting cells (APCs) by targeting Toll-like receptors (TLRs) and other pattern recognition receptors (PRRs) to promote the production of antigen signals and co-stimulatory signals, which in turn enhance the adaptive immune responses. On the other hand, delivery systems are carrier materials that facilitate antigen presentation by prolonging the bioavailability of the loaded antigens, as well as targeting antigens to lymph nodes or APCs. The adjuvants' action mechanisms are systematically summarized at the beginning of this review. This is followed by an introduction of the mechanisms, properties, and progress of classical vaccine adjuvants. Furthermore, since some of the adjuvants under investigation exhibit greater immune activation potency than classical adjuvants, which could compensate for the deficiencies of classical adjuvants, a summary of the adjuvant platforms under investigation is subsequently presented. Notably, we highlight the different action mechanisms and immunological properties of these adjuvant platforms, which will provide a wide range of options for the rational design of different vaccines. On this basis, this review points out the development prospects of vaccine adjuvants and the problems that should be paid attention to in the future.

Human T-cell lymphotropic virus type 1 (HTLV-1) proposed vaccines: a systematic review of preclinical and clinical studies

BACKGROUND

Numerous vaccination research experiments have been conducted on non-primate hosts to prevent or control HTLV-1 infection. Therefore, reviewing recent advancements for status assessment and strategic planning of future preventative actions to reduce HTLV-1 infection and its consequences would be essential.

METHODS

MEDLINE, Scopus, Web of Science, and Clinicaltrials.gov were searched from each database's inception through March 27, 2022. All original articles focusing on developing an HTLV-1 vaccine candidate were included.

RESULTS

A total of 47 studies were included. They used a variety of approaches to develop the HTLV-1 vaccine, including DNA-based, dendritic-cell-based, peptide/protein-based, and recombinant vaccinia virus approaches. The majority of the research that was included utilized Tax, Glycoprotein (GP), GAG, POL, REX, and HBZ as their main peptides in order to develop the vaccine. The immunization used in dendritic cell-based investigations, which were more recently published, was accomplished by an activated CD-8 T-cell response. Although there hasn't been much attention lately on this form of the vaccine, the initial attempts to develop an HTLV-1 immunization depended on recombinant vaccinia virus, and the majority of results seem positive and effective for this type of vaccine. Few studies were conducted on humans. Most of the studies were experimental studies using animal models. Adenovirus, Cytomegalovirus (CMV), vaccinia, baculovirus, hepatitis B, measles, and pox were the most commonly used vectors.

CONCLUSIONS

This systematic review reported recent progression in the development of HTLV-1 vaccines to identify candidates with the most promising preventive and therapeutic effects.

Recombinant GPEHT Fusion Protein Derived from HTLV-1 Proteins with Alum Adjuvant Induces a High Immune Response in Mice

The human T-cell leukemia virus type 1 (HTLV-1) is a positive single-stranded RNA virus that belongs to the delta retrovirus family. As a result, a vaccine candidate that can be recognized by B cells and T cells is a good candidate for generating a durable immune response. Further, the GPEHT protein is a multi-epitope protein designed based on the Gag, Pol, Env, Hbz, and Tax proteins of HTLV-1. In developing a suitable and effective vaccine against HTLV-1, the selection of a designed protein (GPEHT) with the formulation of an alum adjuvant was conducted. In this study, we assessed the potential of a multi-epitope vaccine candidate for stimulating the immune response against HTLV-1. In assessing the type of stimulated immune reaction, total IgG, IgG1, and IgG2a isotypes, as well as the cytokines associated with Th1 (IFN-γ), Th2 (IL-4), and Th17 (IL-17), were analyzed. The outcomes showed that the particular antisera (total IgG) were more elevated in mice that received the GPEHT protein with the alum adjuvant than those in the PBS+Alum control. A subcutaneous vaccination with our chimera protein promoted high levels of IgG1 and IgG2a isotypes. Additionally, IFN-γ, IL-4, and IL-17 levels were significantly increased after spleen cell stimulation in mice that received the GPEHT protein. The immunogenic analyses revealed that the GPEHT vaccine candidate could generate humoral and cell-mediated immune reactions. Ultimately, this study suggests that GPEHT proteins developed with an alum adjuvant can soon be considered as a prospective vaccine to more accurately evaluate their protective efficacy against HTLV-1.

Advances in preventive vaccine development against HTLV-1 infection: A systematic review of the last 35 years

Introduction

The Human T-lymphotropic virus type 1 (HTLV-1) was the first described human retrovirus. It is currently estimated that around 5 to 10 million people worldwide are infected with this virus. Despite its high prevalence, there is still no preventive vaccine against the HTLV-1 infection. It is known that vaccine development and large-scale immunization play an important role in global public health. To understand the advances in this field we performed a systematic review regarding the current progress in the development of a preventive vaccine against the HTLV-1 infection.

Methods

This review followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA®) guidelines and was registered at the International Prospective Register of Systematic Reviews (PROSPERO). The search for articles was performed in PubMed, Lilacs, Embase and SciELO databases. From the 2,485 articles identified, 25 were selected according to the inclusion and exclusion criteria.

Results

The analysis of these articles indicated that potential vaccine designs in development are available, although there is still a paucity of studies in the human clinical trial phase.

Discussion

Although HTLV-1 was discovered almost 40 years ago, it remains a great challenge and a worldwide neglected threat. The scarcity of funding contributes decisively to the inconclusiveness of the vaccine development. The data summarized here intends to highlight the necessity to improve the current knowledge of this neglected retrovirus, encouraging for more studies on vaccine development aiming the to eliminate this human threat.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier (CRD42021270412).

Development of a Novel HTLV-1 Protease: Human Fcγ1 Recombinant Fusion Molecule in the CHO Eukaryotic Expression System

Human T-cell leukaemia virus type 1 (HTLV-1) is the causative agent of two life-threatening diseases, adult T cell leukaemia/lymphoma (ATLL), and HTLV-1-associated myelopathy/tropical spastic (HAM/TSP). HTLV-1 protease (HTLV-1-PR) is an aspartic protease that represents a promising target for therapeutic purposes like human immunodeficiency virus-PR inhibitors (HIV-PR). Therefore, in this study, the human Fc fusion recombinant-PR (HTLV-1-PR:hFcγ1) was designed and expressed for two applications, finding a blocking substrate as a potential therapeutic or a potential subunit peptide vaccine. The PCR amplified DNA sequences encoding the HTLV-1-PR from the MT2-cell line using specific primers with restriction enzyme sites of Not1 and Xba1. The construct was then cloned to pTZ57R/T TA plasmid and, after confirming the PR sequence, subcloned into the pDR2ΔEF1α Fc-expression vector to create pDR2ΔEF1α.HTLV-1-PR:hFcγ1. The integrity of recombinant DNA was confirmed by sequencing to ensure that the engineered construct was in the frame. The recombinant fusion protein was then produced in the Chinese hamster ovary cell (CHO) system and was purified from its supernatant using HiTrap-rPA column affinity chromatography. Then, the immunofluorescence assay (IFA) co-localisation method showed that HTLV-1-PR:hFc recombinant fusion protein has appropriate folding as it binds to the anti-Fcγ antibody; the Fcγ1 tag participates to have HTLV-1-PR:hFcγ1 as a dimeric secretory protein. The development and production of HTLV-1-PR can be used to find a blocking substrate as a potential therapeutic molecule and apply it in an animal model to assess its immunogenicity and potential protection against HTLV-1 infection.