Fc effector of anti-Aß antibody induces synapse loss and cognitive deficits in Alzheimer's disease-like mouse model.

Passive immunotherapy is one of the most promising interventions for Alzheimer's disease (AD). However, almost all immune-modulating strategies fail in clinical trials with unclear causes although they attenuate neuropathology and cognitive deficits in AD animal models. Here, we showed that Aß-targeting antibodies including their lgG1 and lgG4 subtypes induced microglial engulfment of neuronal synapses by activating CR3 or FcγRIIb via the complex of Aß, antibody, and complement. Notably, anti-Aß antibodies without Fc fragment, or with blockage of CR3 or FcγRIIb, did not exert these adverse effects. Consistently, Aß-targeting antibodies, but not their Fab fragments, significantly induced acute microglial synapse removal and rapidly exacerbated cognitive deficits and neuroinflammation in APP/PS1 mice post-treatment, whereas the memory impairments in mice were gradually rescued thereafter. Since the recovery rate of synapses in humans is much lower than that in mice, our findings may clarify the variances in the preclinical and clinical studies assessing AD immunotherapies. Therefore, Aß-targeting antibodies lack of Fc fragment, or with reduced Fc effector function, may not induce microglial synaptic pruning, providing a safer and more efficient therapeutic alternative for passive immunotherapy for AD.

The immunodominant and neutralization linear epitopes for SARS-CoV-2.

Although vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are under development, the antigen epitopes on the virus and their immunogenicity are poorly understood. Here, we simulate the 3D structures and predict the B cell epitopes on the spike (S), envelope (E), membrane (M), and nucleocapsid (N) proteins of SARS-CoV-2 using structure-based approaches and validate epitope immunogenicity by immunizing mice. Almost all 33 predicted epitopes effectively induce antibody production, six of these are immunodominant epitopes in individuals, and 23 are conserved within SARS-CoV-2, SARS-CoV, and bat coronavirus RaTG13. We find that the immunodominant epitopes of individuals with domestic (China) SARS-CoV-2 are different from those of individuals with imported (Europe) SARS-CoV-2, which may be caused by mutations on the S (G614D) and N proteins. Importantly, we find several epitopes on the S protein that elicit neutralizing antibodies against D614 and G614 SARS-CoV-2, which can contribute to vaccine design against coronaviruses.

Superparamagnetic iron oxide nanoparticles conjugated with Aß oligomer-specific scFv antibody and class A scavenger receptor activator show therapeutic potentials for Alzheimer's Disease.

BACKGROUND: Alzheimer's disease (AD) is a progressive neurodegenerative disorder. No disease-modifying strategy to prevent or delay AD progression currently exists. Aß oligomers (AßOs), rather than monomers or fibrils, are considered as the primary neurotoxic species. Therapeutic approaches that direct against AßOs and promote Aß clearance may have great value for AD treatment. RESULTS: We here reported a multifunctional superparamagnetic iron oxide nanoparticle conjugated with Aß oligomer-specific scFv antibody W20 and class A scavenger receptor activator XD4 (W20/XD4-SPIONs). Besides the diagnostic value, W20/XD4-SPIONs retained the anti-Aß properties of W20 and XD4 by inhibiting Aß aggregation, attenuating AßO-induced cytotoxicity and increasing microglial phagocytosis of Aß. When applied to APP/PS1 mice, W20/XD4-SPIONs significantly rescued cognitive deficits and alleviated neuropathology of AD mice. CONCLUSION: These results suggest that W20/XD4-SPIONs show therapeutic benefits for AD. In combination with the early diagnostic property, W20/XD4-SPIONs present as a promising agent for early-stage AD diagnosis and intervention.

Multifunctional Superparamagnetic Iron Oxide Nanoparticles Conjugated with Aß Oligomer-Specific scFv Antibody and Class A Scavenger Receptor Activator Show Early Diagnostic Potentials for Alzheimer's Disease.

BACKGROUND: Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the most common cause of dementia. Diagnosing AD before symptoms arise will facilitate earlier intervention. The early diagnostic approaches are thus urgently needed. METHODS: The multifunctional nanoparticles W20/XD4-SPIONs were constructed by the conjugation of oligomer-specific scFv antibody W20 and class A scavenger receptor (SR-A) activator XD4 onto superparamagnetic iron oxide nanoparticles (SPIONs). The SPIONs' stability and uniformity in size were measured by dynamic light scattering and transmission electron microscopy. The ability of W20/XD4-SPIONs for recognizing Aß oligomers (AßOs) and promoting AßOs phagocytosis was assessed by immunocytochemistry and flow cytometry analysis. The blood-brain barrier permeability of W20/XD4-SPIONs was determined by a co-culture transwell model. The in vivo probe distribution of W20/XD4-SPIONs in AD mouse brains was detected by magnetic resonance imaging (MRI). RESULTS: W20/XD4-SPIONs, as an AßOs-targeted molecular MRI contrast probe, readily reached pathological AßOs regions in brains and distinguished AD transgenic mice from WT controls. W20/XD4-SPIONs retained the property of XD4 for SR-A activation and significantly promoted microglial phagocytosis of AßOs. Moreover, W20/XD4-SPIONs exhibited the properties of good biocompatibility, high stability and low cytotoxicity. CONCLUSION: Compared with W20-SPIONs or XD4-SPIONs, W20/XD4-SPIONs show the highest efficiency for AßOs-targeting and significantly enhance AßOs uptake by microglia. As a molecular probe, W20/XD4-SPIONs also specifically and sensitively bind to AßOs in AD brains to provide an MRI signal, demonstrating that W20/XD4-SPIONs are promising diagnostic agents for early-stage AD. Due to the beneficial effect of W20 and XD4 on neuropathology, W20/XD4-SPIONs may also have therapeutic potential for AD .

Yeast-Based Aß1-15 Vaccine Elicits Strong Immunogenicity and Attenuates Neuropathology and Cognitive Deficits in Alzheimer's Disease Transgenic Mice.

Immunotherapy focusing on reducing the amyloid-beta (Aß) burden is a promising treatment strategy for Alzheimer's disease (AD). Many clinical studies on AD immunotherapies have failed due to low safety and efficacy, calling for a highly potent AD vaccine which induces sufficient antibody titer while avoiding side effects. Here, we designed a yeast-based vaccine Y-5A15 comprising five copies of Aß1-15 displayed on the surface of yeast cell wall, and we subcutaneously immunized APP/PS1 mice three times. Our results demonstrated that the Y-5A15 remarkably enhanced the Aß epitope immunogenicity and elicited high antibody titers against Aß in AD mice. Importantly, Y-5A15 vaccination successfully reduced Aß levels, plaque burden and glial activation, rescued synaptic deficits and significantly ameliorated memory and cognitive decline in APP/PS1 transgenic mice, suggesting that the yeast-based Aß epitope vaccine has a promising potency for the treatment of AD.

A novel rapid modularized hepatitis B core virus-like particle-based platform for personalized cancer vaccine preparation via fixed-point coupling.

Personalized cancer vaccine which targets neoepitopes shows great promise for cancer treatment. However, rapid preparation is a critical challenge for clinical application of personalized cancer vaccine. Genetic recombination and chemical modification are a time-consuming "trial and error" pattern for making vaccines. Here we first constructed a platform for peptide vaccine preparation by inserting SpyCatcher into the major immunodominant region (MIR) of hepatitis B core protein (HBc) (1-183). The resulted recombinant protein HBc(1-183)-SpyCatcher (HBc(1-183)-S) assembled to virus-like particles (VLPs) and readily bound to SpyTag conjugated with OVA epitope peptides by just mixing, forming HBc(1-183)-S-OVA. HBc(1-183)-S-OVA VLPs effectively induced dendritic cell maturation. Our further results indicated that HBc(1-183)-S-OVA VLPs vaccination inhibited tumor growth in both prophylactic and treatment ways in E.G7-OVA tumor bearing mice by generating significant OVA-specific cytotoxic T lymphocyte responses. Our study provides a simple, rapid, efficient and universal HBc-based platform for the preparation of personalized cancer vaccine.

A biomimetic yeast shell vaccine coated with layered double hydroxides induces a robust humoral and cellular immune response against tumors.

Enhancing both the humoral and cellular immune response for tumor vaccination remains a challenge. Inspired by natural pathogen structures, we took ß-glucan particles derived from a baker's yeast cell shell (YS) as a vaccine carrier and danger signal for dendritic cells (DCs), and coated the YS with catanionic layered double hydroxides (LDH) by electrostatic adsorption to form a biomimetic yeast cell particle (YSL). Our experimental results showed that the YSL vaccine efficiently targeted antigen-presenting cells (APCs) and remarkably enhanced antigen cross-presentation, and strongly improved the activation and maturation of DCs. Moreover, the YSL vaccine elicited an extremely high antibody titer and strong antigen-specific cytotoxic T lymphocyte together with mixed Th1/Th17 cellular immune responses and induced marked prophylactic and therapeutic effects against E.G7-OVA tumors in mouse models. These results suggest that YSL, integrating a yeast shell to mimic natural pathogens and LDH with high antigen-loading capacity and lysosome escape, is a promising tumor vaccine platform for rapid, effective and strong induction of both humoral and cellular immune responses.

ScFv-conjugated superparamagnetic iron oxide nanoparticles for MRI-based diagnosis in transgenic mouse models of Parkinson's and Huntington's diseases.

It is widely accepted that amyloid oligomers are the most toxic species to initiate the pathologic processes of Parkinson's disease (PD) and Huntingdon's disease (HD). But there is no definitive diagnosis for PD and HD at their early stages. Here, we conjugated an amyloid oligomer-specific scFv antibody (W20) to PEGylated superparamagnetic iron oxide nanoparticles (SPIONs) and detected the properties of the SPIONs conjugated with W20. The results showed that W20-SPIONs, with the size of around 11.8 nm in diameter, were stable and nontoxic, and had enough relaxation capacity to be used as an MRI contrast agent. When applied to the transgenic mouse models of PD and HD, W20-SPIONs crossed the blood-brain barrier and specifically bound to the oligomer area to give MRI signal, distinguishing PD and HD from healthy controls. These results indicated that W20-SPIONs had potential in early-stage diagnosis for PD and HD and also opened up a new strategy for evaluating the efficacy of new drugs.

Hepatitis B core VLP-based mis-disordered tau vaccine elicits strong immune response and alleviates cognitive deficits and neuropathology progression in Tau.P301S mouse model of Alzheimer's disease and frontotemporal dementia.

BACKGROUND: Truncated mis-disordered tau protein plays an important role in the pathogenesis of Alzheimer's disease (AD) and frontotemporal dementia (FTD). Tau294-305, an epitope in the truncated tau, is essential for pathological tau-tau interaction and aggregation. A tau294-305-targeted approach may have beneficial effects in the treatment of AD and FTD. METHODS: In this study, we genetically fused tau294-305 epitope to the hepatitis B virus core protein (HBc) major immunodominant region (MIR) (with the resultant protein termed T294-HBc), and we subcutaneously immunized a Tau.P301S transgenic mouse model of FTD and AD with T294-HBc four times. The levels and characteristics of antibodies induced by T294-HBc were determined by enzyme-linked immunosorbent assay. The effect of T294-HBc on the cognitive deficits of Tau.P301S mice was tested using the Morris water maze test, novel object recognition, and a Y-maze test. Western blot analysis and IHC were applied to measure the effect of T294-HBc on tau pathologies and neuroinflammation in the mouse brains. RESULTS: The results showed that T294-HBc self-assembled into HBc chimeric virus-like particles (VLPs) with tau294-305 displayed on the surface and that it induced high antibody titers specifically against the mis-disordered truncated tau. Further investigation showed that these antibodies simultaneously bound to microtubule-binding regions 1-4 (MTBR1-4) [tau263-274, tau294-305, tau325-336, tau357-368 and tau294-305(P301S)]. Moreover, T294-HBc VLP vaccination significantly ameliorated memory and cognitive decline; reduced the levels of AT8-positive tau, truncated tau monomer, and oligomer; attenuated microgliosis and astrogliosis; and rescued synaptic deficits in Tau.P301S transgenic mice. CONCLUSIONS: T294-HBc VLP vaccine elicited strong immune response and alleviated cognitive deficits and neuropathology progression in Tau.P301S mice, indicating that the T294-HBc VLP vaccine has promising therapeutic potential for the treatment of AD and FTD.

Efficient co-delivery of neo-epitopes using dispersion-stable layered double hydroxide nanoparticles for enhanced melanoma immunotherapy.

Cancer immunotherapy has shown tremendous progresses in recent years for various cancers and layered double hydroxide (LDH) nanoparticles are demonstrated as effective adjuvants for protein-based vaccines. This research further shows that the colloidal stability of LDH-based vaccines significantly influences the therapeutic efficacy and LDH nanoparticles are able to adjuvant multiple tumor-associated antigen peptides to provoke strong cell-mediated immune responses for effective inhibition of cancer growth. The LDH-based multi-target therapeutic vaccines were constructed by assembling epitope peptides and CpG onto LDH nanoparticles. Using melanoma as the model cancer and Tyrosinase-related protein 2 (Trp2) peptide as the model antigen, we demonstrated that dispersion-stable LDH-based vaccine induced stronger cytotoxic T-lymphocyte (CTL) responses and significantly inhibited tumor growth in comparison with aggregated LDH-based vaccine. We further constructed multi-target dispersion-stable LDH-based vaccine by co-loading Trp2, two mutated epitopes (M27 and M30) and CpG, which showed remarkable inhibition of melanoma growth. These results suggest that dispersion-stable LDH nanoparticles are an ideal platform to load multi-antigens and immune stimulants as effective personalized therapeutic cancer vaccines.

Fruitless Wolfberry-Sprout Extract Rescued Cognitive Deficits and Attenuated Neuropathology in Alzheimer's Disease Transgenic Mice.

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative disease featured by memory loss, neuroinflammation and oxidative stress. Overproduction or insufficient clearance of Aß leads to its pathological aggregation and deposition, which is considered the predominant neuropathological hallmark of AD. Therefore, reducing Aß levels and inhibiting Aß-induced neurotoxicity are feasible therapeutic strategies for AD treatment. Wolfberry has been traditionally used as a natural antioxidant and anti-aging product. However, whether wolfberry species has therapeutic potential on AD remains unknown. METHOD: The effects of fruitless wolfberry-sprout extract (FWE) on Aß fibrillation and fibril disaggregation was measured by thioflavin T fluorescence and transmission electron microscope imaging; Aß oligomer level was determined by dot-blot; Cell viability and apoptosis was assessed by MTT and TUNEL assay. The levels of Aß40/42, oxidative stress biomarkers and inflammatory cytokines were detected by corresponding kits. 8-month-old male APP/PS1 mice and their age-matched WT littermates were treated with FWE or vehicle by oral administration (gavage) once a day for 4 weeks. Then the cognitive performance was determined using object recognition test and Y-maze test. The Aß burden and gliosis was evaluated by immunostaining and immunoblotting, respectively. RESULTS: FWE significantly inhibited Aß fibrillation and disaggregated the formed Aß fibrils, lowered Aß oligomer level and Aß-induced neuro-cytotoxicity, and attenuated oxidative stress in vitro. Oral administration of FWE remarkably improved cognitive function, reduced Aß burden, decreased gliosis and inflammatory cytokines release, and ameliorated oxidative stress in the brains of APP/PS1 mice. CONCLUSION: These findings indicate that FWE is a promising natural agent for AD treatment.

An indoleamine 2, 3-dioxygenase siRNA nanoparticle-coated and Trp2-displayed recombinant yeast vaccine inhibits melanoma tumor growth in mice.

Therapeutic vaccine is a promising approach in cancer therapy. But tumor-associated antigen peptides have weak immunogenicity and cancer patients are often characterized by immunosuppression and tolerance, leading to less efficiency of immunotherapy. We here successfully developed indoleamine 2, 3-dioxygenase (IDO) siRNA nanoparticle-coated and tyrosinase-related protein 2 (Trp2)-displayed recombinant Saccharomyces cerevisiae (YCP). YCPs had positive charges with a diameter of approximately 5µm, resulting in selective phagocytosis by APC cells. YCP-delivered siRNA and Trp2 successfully escaped from phagosomes, efficiently inhibited IDO expression in DCs, promoted the immune reaction of T cell against Trp2, increased the secretion of proinflammatory cytokines such as IFN-γ,TNF-α, and IL-6, and decreased the generation of regulatory T cells. Moreover, YCPs significantly inhibited melanoma tumor growth by alleviating immune tolerance and promoting Trp2-specific CD8+ T cell immune response. These results suggest that Saccharomyces cerevisiae as a combined immunotherapeutic platform to simultaneously delivery IDO-siRNA and Trp2 epitope peptide is a promising vaccine system for melanoma treatment.

A mimotope of Aß oligomers may also behave as a ß-sheet inhibitor.

Beta-amyloid (Aß) oligomers are strongly associated with the cascade of harmful events leading to neurodegeneration in Alzheimer's disease (AD). Elimination of Aß oligomers or inhibition of Aß assembly is a valuable therapeutic approach for the treatment of AD. Here, we obtained a mimotope of Aß oligomers, AOEP2, by screening a peptide library using oligomer-specific antibodies. The antibodies induced by AOEP2 specifically recognize Aß oligomers rather than monomers and fibrils. Interestingly, the AOEP2 peptide binds to Aß monomers and inhibits the formation of Aß oligomers and ß-sheet structure, reduces Aß42-induced neurotoxicity, and decreases the release of proinflammatory cytokines. Taken together, AOEP2, a novel multifunctional peptide directly or indirectly targeting Aß, has promising therapeutic potential for AD.

A vaccine with Aß oligomer-specific mimotope attenuates cognitive deficits and brain pathologies in transgenic mice with Alzheimer's disease.

BACKGROUND: ß-Amyloid peptide (Aß) oligomers are initial factors used to induce Alzheimer's disease (AD) development, and Aß monomers have normal physiological function. The antibodies or vaccines against Aß monomers have serious problems, such as side effects and low curative effects. Therefore, it is essential to specifically target Aß oligomers rather than monomers for the treatment of AD. METHODS: The mimotopes of Aß oligomers were obtained by panning the phage-displayed random peptide libraries using oligomer-specific antibodies as targets and expressed on the surface of EBY100 Saccharomyces cerevisiae to generate yeast cell base vaccines. One vaccine (AOE1) induced antibodies specifically against Aß oligomers and was selected for further study. The APP/PS1 mice were subcutaneously immunized with AOE1 eight times. The levels and characteristics of antibodies induced by AOE1 were determined by enzyme-linked immunosorbent assay. The effect of AOE1 on the cognitive deficits of AD mice was tested by novel object recognition (NOR) and Y-maze. Dot blot analysis, Western blot analysis, and immunohistochemistry were applied to measure the effects of AOE1 on Aß pathologies, neuroinflammation, and microhemorrhages in the brains of AD mice. RESULTS: Eight mimotope candidates of Aß oligomers were selected and expressed on EBY100 S. cerevisiae. Only AOE1 vaccine containing mimotope L2 induced antibodies that specifically recognized Aß42 oligomers rather than monomers. AOE1 immunization significantly increased the AD mice's exploration times for the novel object in the NOR test and the choices for new arms in the Y-maze test, and it reduced levels of Aß oligomers and glial activation in the AD mouse brains. No activation of Aß-specific T cells and microhemorrhages was observed in their brains following AOE1 vaccination. CONCLUSIONS: AOE1 is the first vaccine applying the oligomer-specific mimotope as an immunogen, which could induce antibodies with high specificity to Aß oligomers. AOE1 immunization attenuated Aß pathologies and cognitive deficits in AD mice, decreased the overactivation of glial cells, and did not induce microhemorrhage in the brains of AD mice. These findings suggest that AOE1 may be a safer and more effective vaccine for AD treatment.

MgAl-layered double hydroxide nanoparticles co-delivering siIDO and Trp2 peptide effectively reduce IDO expression and induce cytotoxic T-lymphocyte responses against melanoma tumor in mice.

Active immunotherapy has shown promising potential for cancer treatment. However, there still remain major challenges including induction of a potent and specific T-cell response against the endogenous antigen and retention of tumor immunity. To address these problems, we used layered double hydroxide (LDH) nanoparticles (NPs) to co-deliver tyrosinase-related protein 2 (Trp2) and indoleamine 2,3-dioxygenase siRNA (siIDO) to dendritic cells (DCs). These LDH NPs were readily taken in by DCs, and escaped from endosomes into the cytoplasm. Compared with free Trp2 peptide or siIDO, the vaccination with the LDH NPs co-delivering Trp2 and siIDO significantly inhibited tumor growth in melanoma mouse models by relieving IDO-mediated immune suppression and increasing naïve and specific T cell activation process in vivo. Thus, these LDH NPs, which have a high loading capacity for peptide or siRNA effectively protect and deliver Trp2 and siIDO, overcome the immune tolerance and strengthen T cell immunity, are potential therapeutics to enhance cancer treatment.

Interleukin-1ß-Targeted Vaccine Improves Glucose Control and ß-Cell Function in a Diabetic KK-Ay Mouse Model.

Interleukin-1ß (IL-1ß) has been implicated as a key proinflammatory cytokine involved in the pancreatic islet inflammation of type 2 diabetes mellitus (T2DM). Excess IL-1ß impairs islet function by inducing insulin resistance and ß-cell apoptosis. Therefore, specifically reducing IL-1ß activity provides a therapeutic improvement for T2DM by sustaining the inhibition of IL-1ß-mediated islet inflammation. In this study, we developed an IL-1ß-targeted epitope peptide vaccine adjuvanted with polylactic acid microparticles (1ßEPP) and applied it to a diabetic KK-Ay mouse model. Results showed that the 1ßEPP elicited high antibody responses, which neutralized the biological activity of IL-1ß, and induced barely detectable inflammatory activity. 1ßEPP immunization reduced body weight gain, protected KK-Ay mice from hyperglycemia, improved glucose tolerance and insulin sensitivity, and decreased the serum levels of free fatty acids, total cholesterol and triglyceride. Moreover, 1ßEPP restored ß-cell mass; inhibited ß-cell apoptosis; decreased the expression of IL-1ß; and interrupted NF-κB activation by reducing IKKß and pRelA levels. These studies indicated that the IL-1ß-targeted vaccine may be a promising immunotherapeutic for T2DM treatment.