Novel Vaccine against Pathological Pyroglutamate-Modified Amyloid Beta for Prevention of Alzheimer's Disease.

Post-translationally modified N-terminally truncated amyloid beta peptide with a cyclized form of glutamate at position 3 (pE3Aß) is a highly pathogenic molecule with increased neurotoxicity and propensity for aggregation. In the brains of Alzheimer's Disease (AD) cases, pE3Aß represents a major constituent of the amyloid plaque. The data show that pE3Aß formation is increased at early pre-symptomatic disease stages, while tau phosphorylation and aggregation mostly occur at later stages of the disease. This suggests that pE3Aß accumulation may be an early event in the disease pathogenesis and can be prophylactically targeted to prevent the onset of AD. The vaccine (AV-1986R/A) was generated by chemically conjugating the pE3Aß3-11 fragment to our universal immunogenic vaccine platform MultiTEP, then formulated in AdvaxCpG adjuvant. AV-1986R/A showed high immunogenicity and selectivity, with endpoint titers in the range of 105-106 against pE3Aß and 103-104 against the full-sized peptide in the 5XFAD AD mouse model. The vaccination showed efficient clearance of the pathology, including non-pyroglutamate-modified plaques, from the mice brains. AV-1986R/A is a novel promising candidate for the immunoprevention of AD. It is the first late preclinical candidate which selectively targets a pathology-specific form of amyloid with minimal immunoreactivity against the full-size peptide. Successful translation into clinic may offer a new avenue for the prevention of AD via vaccination of cognitively unimpaired individuals at risk of disease.

A Therapeutic Vaccine Targeting Rat BORIS (CTCFL) for the Treatment of Rat Breast Cancer Tumors.

Cancer testis antigens are ideal for tumor immunotherapy due to their testis-restricted expression. We previously showed that an immunotherapeutic vaccine targeting the germ cell-specific transcription factor BORIS (CTCFL) was highly effective in treating aggressive breast cancer in the 4T1 mouse model. Here, we further tested the therapeutic efficacy of BORIS in a rat 13762 breast cancer model. We generated a recombinant VEE-VRP (Venezuelan Equine Encephalitis-derived replicon particle) vector-expressing modified rat BORIS lacking a DNA-binding domain (VRP-mBORIS). Rats were inoculated with the 13762 cells, immunized with VRP-mBORIS 48 h later, and then, subsequently, boosted at 10-day intervals. The Kaplan-Meier method was used for survival analysis. Cured rats were re-challenged with the same 13762 cells. We demonstrated that BORIS was expressed in a small population of the 13762 cells, called cancer stem cells. Treatment of rats with VRP-BORIS suppressed tumor growth leading to its complete disappearance in up to 50% of the rats and significantly improved their survival. This improvement was associated with the induction of BORIS-specific cellular immune responses measured by T-helper cell proliferation and INFγ secretion. The re-challenging of cured rats with the same 13762 cells indicated that the immune response prevented tumor growth. Thus, a therapeutic vaccine against rat BORIS showed high efficacy in treating the rat 13762 carcinoma. These data suggest that targeting BORIS can lead to the elimination of mammary tumors and cure animals even though BORIS expression is detected only in cancer stem cells.

Immunogenicity of MultiTEP platform technology-based Tau vaccine in non-human primates.

Pathological forms of Tau protein are directly associated with neurodegeneration and correlate with Alzheimer's Disease (AD) symptoms, progression, and severity. Previously, using various mouse models of Tauopathies and AD, we have demonstrated the immunogenicity and efficacy of the MultiTEP-based adjuvanted vaccine targeting the phosphatase activating domain (PAD) of Tau, AV-1980R/A. Here, we analyzed its immunogenicity in non-human primates (NHP), the closest phylogenic relatives to humans with a similar immune system, to initiate the transition of this vaccine into clinical trials. We have demonstrated that AV-1980R/A is highly immunogenic in these NHPs, activating a broad but unique to each monkey repertoire of MultiTEP-specific T helper (Th) cells that, in turn, activate B cells specific to PAD. The resulting anti-PAD IgG antibodies recognize pathological Tau tangles and Tau-positive neuritis in AD case brain sections with no staining in control non-AD cases. These published data and efficacy results support the AV-1980R/A vaccine progression to first-in-human clinical trials.

Immunogenicity of MultiTEP-Platform-Based Recombinant Protein Vaccine, PV-1950R, Targeting Three B-Cell Antigenic Determinants of Pathological α-Synuclein.

Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are characterized by the aberrant accumulation of intracytoplasmic misfolded and aggregated α-synuclein (α-Syn), resulting in neurodegeneration associated with inflammation. The propagation of α-Syn aggregates from cell to cell is implicated in the spreading of pathological α-Syn in the brain and disease progression. We and others demonstrated that antibodies generated after active and passive vaccinations could inhibit the propagation of pathological α-Syn in the extracellular space and prevent/inhibit disease/s in the relevant animal models. We recently tested the immunogenicity and efficacy of four DNA vaccines on the basis of the universal MultiTEP platform technology in the DLB/PD mouse model. The antibodies generated by these vaccines efficiently reduced/inhibited the accumulation of pathological α-Syn in the different brain regions and improved the motor deficit of immunized female mice. The most immunogenic and preclinically effective vaccine, PV-1950D, targeting three B-cell epitopes of pathological α-Syn simultaneously, has been selected for future IND-enabling studies. However, to ensure therapeutically potent concentrations of α-Syn antibodies in the periphery of the vaccinated elderly, we developed a recombinant protein-based MultiTEP vaccine, PV-1950R/A, and tested its immunogenicity in young and aged D-line mice. Antibody responses induced by immunizations with the PV-1950R/A vaccine and its homologous DNA counterpart, PV-1950D, in a mouse model of PD/DLB have been compared.

Efficacy and immunogenicity of MultiTEP-based DNA vaccines targeting human α-synuclein: prelude for IND enabling studies.

Accumulation of misfolded proteins such as amyloid-ß (Aß), tau, and α-synuclein (α-Syn) in the brain leads to synaptic dysfunction, neuronal damage, and the onset of relevant neurodegenerative disorder/s. Dementia with Lewy bodies (DLB) and Parkinson's disease (PD) are characterized by the aberrant accumulation of α-Syn intracytoplasmic Lewy body inclusions and dystrophic Lewy neurites resulting in neurodegeneration associated with inflammation. Cell to cell propagation of α-Syn aggregates is implicated in the progression of PD/DLB, and high concentrations of anti-α-Syn antibodies could inhibit/reduce the spreading of this pathological molecule in the brain. To ensure sufficient therapeutic concentrations of anti-α-Syn antibodies in the periphery and CNS, we developed four α-Syn DNA vaccines based on the universal MultiTEP platform technology designed especially for the elderly with immunosenescence. Here, we are reporting on the efficacy and immunogenicity of these vaccines targeting three B-cell epitopes of hα-Syn aa85-99 (PV-1947D), aa109-126 (PV-1948D), aa126-140 (PV-1949D) separately or simultaneously (PV-1950D) in a mouse model of synucleinopathies mimicking PD/DLB. All vaccines induced high titers of antibodies specific to hα-Syn that significantly reduced PD/DLB-like pathology in hα-Syn D line mice. The most significant reduction of the total and protein kinase resistant hα-Syn, as well as neurodegeneration, were observed in various brain regions of mice vaccinated with PV-1949D and PV-1950D in a sex-dependent manner. Based on these preclinical data, we selected the PV-1950D vaccine for future IND enabling preclinical studies and clinical development.

Characterization and preclinical evaluation of the cGMP grade DNA based vaccine, AV-1959D to enter the first-in-human clinical trials.

The DNA vaccine, AV-1959D, targeting N-terminal epitope of Aß peptide, has been proven immunogenic in mice, rabbits, and non-human primates, while its therapeutic efficacy has been shown in mouse models of Alzheimer's disease (AD). Here we report for the first time on IND-enabling biodistribution and safety/toxicology studies of cGMP-grade AV-1959D vaccine in the Tg2576 mouse model of AD. We also tested acute neuropathology safety profiles of AV-1959D in another AD disease model, Tg-SwDI mice with established vascular and parenchymal Aß pathology in a pre-clinical translational study. Biodistribution studies two days after the injection demonstrated high copy numbers of AV-1959D plasmid after single immunization of Tg2576 mice at the injection sites but not in the tissues of distant organs. Plasmids persisted at the injection sites of some mice 60 days after vaccination. In Tg2576 mice with established amyloid pathology, we did not observe short- or long-term toxicities after multiple immunizations with three doses of AV-1959D. Assessment of the repeated dose acute safety of AV-1959D in cerebral amyloid angiopathy (CAA) prone Tg-SwDI mice did not reveal any immunotherapy-induced vasogenic edema detected by magnetic resonance imaging (MRI) or increased microhemorrhages. Multiple immunizations of Tg-SwDI mice with AV-1959D did not induce T and B cell infiltration, glial activation, vascular deposition of Aß, or neuronal degeneration (necrosis and apoptosis) greater than that in the control group determined by immunohistochemistry of brain tissues. Taken together, the safety data from two different mouse models of AD substantiate a favorable safety profile of the cGMP grade AV-1959D vaccine supporting its progression to first-in-human clinical trials.

Testing a MultiTEP-based combination vaccine to reduce Aß and tau pathology in Tau22/5xFAD bigenic mice.

BACKGROUND: Alzheimer disease (AD) is characterized by the accumulation of beta-amyloid (Aß) plaques and neurofibrillary tangles composed of hyperphosphorylated tau, which together lead to neurodegeneration and cognitive decline. Current therapeutic approaches have primarily aimed to reduce pathological aggregates of either Aß or tau, yet phase 3 clinical trials of these approaches have thus far failed to delay disease progression in humans. Strong preclinical evidence indicates that these two abnormally aggregated proteins interact synergistically to drive downstream neurodegeneration. Therefore, combinatorial therapies that concurrently target both Aß and tau might be needed for effective disease modification. METHODS: A combinatorial vaccination approach was designed to concurrently target both Aß and tau pathologies. Tau22/5xFAD (T5x) bigenic mice that develop both pathological Aß and tau aggregates were injected intramuscularly with a mixture of two MultiTEP epitope vaccines: AV-1959R and AV-1980R, targeting Aß and tau, respectively, and formulated in AdvaxCpG, a potent polysaccharide adjuvant. Antibody responses of vaccinated animals were measured by ELISA, and neuropathological changes were determined in brain homogenates of vaccinated and control mice using ELISA and Meso Scale Discovery (MSD) multiplex assays. RESULTS: T5x mice immunized with a mixture of Aß- and tau-targeting vaccines generated high Aß- and tau-specific antibody titers that recognized senile plaques and neurofibrillary tangles/neuropil threads in human AD brain sections. Production of these antibodies in turn led to significant reductions in the levels of soluble and insoluble total tau, and hyperphosphorylated tau as well as insoluble Aß42, within the brains of bigenic T5x mice. CONCLUSIONS: AV-1959R and AV-1980R formulated with AdvaxCpG adjuvant are immunogenic and therapeutically potent vaccines that in combination can effectively reduce both of the hallmark pathologies of AD in bigenic mice. Taken together, these findings warrant further development of this vaccine technology for ultimate testing in human AD.

A MultiTEP platform-based epitope vaccine targeting the phosphatase activating domain (PAD) of tau: therapeutic efficacy in PS19 mice.

Pathological tau correlates well with cognitive impairments in Alzheimer's disease (AD) patients and therefore represents a promising target for immunotherapy. Targeting an appropriate B cell epitope in pathological tau could in theory produce an effective reduction of pathology without disrupting the function of normal native tau. Recent data demonstrate that the N-terminal region of tau (aa 2-18), termed the "phosphatase activation domain (PAD)", is hidden within native Tau in a 'paperclip'-like conformation. Conversely, PAD is exposed in pathological tau and plays an essential role in the inhibition of fast axonal transport and tau polymerization. Thus, we hypothesized that anti-tau2-18 antibodies may safely and specifically reduce pathological tau and prevent further aggregation, which in turn would neutralize tau toxicity. Therefore, we evaluated the immunogenicity and therapeutic efficacy of our MultiTEP platform-based vaccine targeting tau2-18 formulated with AdvaxCpG adjuvant (AV-1980R/A) in PS19 tau transgenic mice. The AV-1980R/A induced extremely high antibody responses and the resulting sera recognized neurofibrillary tangles and plaque-associated dystrophic neurites in AD brain sections. In addition, under non-denaturing conditions AV-1980R/A sera preferentially recognized AD-associated tau. Importantly, vaccination also prevented age-related motor and cognitive deficits in PS19 mice and significantly reduced insoluble total and phosphorylated tau species. Taken together, these findings suggest that predominantly targeting misfolded tau with AV-1980R/A could represent an effective strategy for AD immunotherapy.

Anticancer Mechanisms in Two Murine Bone Marrow-Derived Dendritic Cell Subsets Activated with TLR4 Agonists.

Dendritic cells (DCs) are well-known for their functions in orchestrating the innate and adaptive arms of immune defense. However, under certain conditions, DCs can exert tumoricidal activity. We have elucidated the mechanism of tumor suppression by TLR4-activated bone marrow-derived DCs (BMDCs) isolated from BALB/c mice. We identified that two distinct subsets of BMDCs (CD11b+CD11c+I-A/Eint and CD11b+CD11c+I-A/Ehigh) have different cytotoxic mechanisms of action. The cytotoxicity of the former subset is mediated through NO and reactive oxygen species and type I IFN (IFN-ß), whereas the latter subset acts only through IFN-ß. TLR4 agonists, LPS or pharmaceutical-grade ImmunoMax, activate CD11c+ BMDCs, which, in turn, directly kill 4T1 mouse breast cancer cells or inhibit their proliferation in an MHC-independent manner. These data define two populations of BMDCs with different mechanisms of direct cytotoxicity, as well as suggest that the I-A/Eint subset could be less susceptible to counteracting mechanisms in the tumor microenvironment and support investigation of similar subsets in human DCs.

MultiTEP platform-based DNA vaccines for alpha-synucleinopathies: preclinical evaluation of immunogenicity and therapeutic potency.

We have previously demonstrated that anti-beta amyloid DNA vaccine (AV-1959D) based on our proprietary MultiTEP platform technology is extremely immunogenic in mice, rabbits, and monkeys. Importantly, MultiTEP platform enables development of vaccines targeting pathological molecules involved in various neurodegenerative disorders. Taking advantage of the universality of MultiTEP platform, we developed DNA vaccines targeting 3 B-cell epitopes (amino acids [aa]85-99, aa109-126, and aa126-140) of human alpha-synuclein (hα-Syn) separately or all 3 epitopes simultaneously. All 4 DNA vaccines (1) generate high titers of anti-hα-Syn antibodies and (2) induce robust MultiTEP-specific T-helper cell responses without activation of potentially detrimental autoreactive anti-hα-Syn T-helper cells. Generated antibodies recognize misfolded hα-Syn produced by neuroblastoma cells, hα-Syn in the brain tissues of transgenic mouse strains and in the brain tissues of dementia with Lewy body cases. Based on these results, the most promising vaccine targeting 3 B-cell epitopes of hα-Syn simultaneously (PV-1950D) has been chosen for ongoing preclinical assessment in mouse models of hα-Syn with the aim to translate it to the human clinical trials.

Humanized monoclonal antibody armanezumab specific to N-terminus of pathological tau: characterization and therapeutic potency.

BACKGROUND: The experience from clinical trials indicates that anti-Aß immunotherapy could be effective in early/pre-clinical stages of AD, whereas at the late stages promoting the clearing of Aß alone may be insufficient to halt the disease progression. At the same time, pathological tau correlates much better with the degree of dementia than Aß deposition. Therefore, targeting pathological tau may provide a more promising approach for the treatment of advanced stages of AD. Recent data demonstrates that the N-terminal region of tau spanning aa 2-18 termed "phosphatase activation domain" that is normally hidden in the native protein in 'paperclip'-like conformation, becomes exposed in pathological tau and plays an essential role in the inhibition of fast axonal transport and in aggregation of tau. Hence, we hypothesized that anti-Tau2-18 monoclonal antibodies (mAb) may recognize pathological, but not normal tau at very early stages of tauopathy and prevent or decrease the aggregation of this molecule. METHODS: Mouse mAbs were generated using standard hybridoma methodology. CDR grafting was used for humanization of mouse mAb. Humanized mAb (Armanezumab) was characterized and tested in vitro/ex vivo/in vivo using biochemical and immunological methods (HPLC, Biacore, ELISA, IHC, FRET, etc.). Stable DG44 cell line expressing Armanezumab was generated by clone selection with increased concentrations of methotrexate (MTX). RESULTS: A panel of mouse mAbs was generated, clone 1C9 was selected based on binding to pathological human tau with high affinity and humanized. Fine epitope mapping revealed conservation of the epitope of human tau recognized by the parent murine mAb and Armanezumab. Importantly, Armanezumab (i) bound to tau with high affinity as determined by Biacore; (ii) bound pathological tau in brains from AD, FTD and Pick's disease cases; (iii) inhibited seeding effect of aggregated tau from brain lysate of P301S Tg mice; (iv) inhibited cytotoxic effect of tau oligomers; (v) reduced total tau (HT7) and AT100, PHF1, AT8, AT180, p212, p214-positive tau species in brains of tau transgenic mice after intracranial injection. A stable CHO cell line producing >1.5 g/l humanized mAb, Armanezumab was generated. CONCLUSION: These findings suggest that Armanezumab could be therapeutic in clinical studies for treatment of AD.

MultiTEP platform-based DNA epitope vaccine targeting N-terminus of tau induces strong immune responses and reduces tau pathology in THY-Tau22 mice.

BACKGROUND: By the time clinical symptoms of Alzheimer's disease (AD) manifest in patients there is already substantial tau pathology in the brain. Recent evidence also suggests that tau pathology can become self-propagating, further accelerating disease progression. Over the last decade several groups have tested the efficacy of protein-based anti-tau immunotherapeutics in various animal models of tauopathy. Here we report on the immunological and therapeutic potency of the first anti-tau DNA vaccine based on the MultiTEP platform, AV-1980D, in THY-Tau22 transgenic mice. METHODS: Starting at 3months of age, mice were immunized intramuscularly with AV-1980D vaccine targeting a tau B cell epitope spanning aa2-18 followed by electroporation (EP). Humoral and cellular immune responses in vaccinated animals were analyzed by ELISA and ELISpot, respectively. Neuropathological changes in the brains of experimental and control mice were then analyzed by biochemical (WB and ELISA) and immunohistochemical (IHC) methods at 9months of age. RESULTS: EP-mediated AV-1980D vaccinations of THY-Tau22 mice induced activation of Th cells specific to the MultiTEP vaccine platform and triggered robust humoral immunity response specific to tau. Importantly, no activation of potentially harmful autoreactive Th cell responses specific to endogenous tau species was detected. The maximum titers of anti-tau antibodies were reached after two immunizations and remained slightly lower, but steady during five subsequent monthly immunizations. Vaccinations with AV-1980D followed by EP significantly reduced total tau and pS199 and AT180 phosphorylated tau levels in the brains extracts of vaccinated mice, but produced on subtle non-significant effects on other phosphorylated tau species. CONCLUSIONS: These data demonstrate that MultiTEP-based DNA epitope vaccination targeting the N-terminus of tau is highly immunogenic and therapeutically potent in the THY-Tau22 mouse model of tauopathy and indicate that EP-mediated DNA immunization is an attractive alternative to protein-based adjuvanted vaccines for inducing high concentrations of anti-tau antibodies.

Comparison of Efficacy of Preventive and Therapeutic Vaccines Targeting the N Terminus of ß-Amyloid in an Animal Model of Alzheimer's Disease.

Previously, we reported that Alzheimer's disease (AD) epitope vaccines (EVs) composed of N-terminal ß-amyloid (Aß42) B cell epitope fused with universal foreign T helper (Th) epitope(s) were immunogenic, potent, and safe in different amyloid precursor protein (APP) transgenic mice with early AD-like pathology. However, developing an effective therapeutic vaccine is much more challenging, especially when a self-antigen such as Aß42 is a target. Here, we directly compare the efficacy of anti-Aß42 antibodies in Tg2576 mice with low or high levels of AD-like pathology at the start of immunizations: 6-6.5 months for preventive vaccinations and 16-19 months for therapeutic vaccinations. EV in a preventive setting induced high levels of anti-Aß antibodies, significantly reducing pathologic forms of Aß in the brains of Tg2576 mice. When used therapeutically for immunesenescent Tg2576 mice, EV induced low levels of antibodies not sufficient for clearing of AD-like pathology. Separately, we demonstrated that EV was also not effective in 11-11.5-month-old Tg2576 mice with moderate AD-like pathology. However, we augmented the titers of anti-Aß antibodies in transgenic (Tg) mice of the same age possessing the pre-existing memory Th cells and detected a significant decrease in diffuse and core plaques in cortical regions compared to control animals along with improved novel object recognition performance.

Alzheimer's disease Advax(CpG)- adjuvanted MultiTEP-based dual and single vaccines induce high-titer antibodies against various forms of tau and Aß pathological molecules.

Although ß-amyloid (Aß) may be the primary driver of Alzheimer's disease (AD) pathology, accumulation of pathological tau correlates with dementia in AD patients. Thus, the prevention/inhibition of AD may require vaccine/s targeting Aß and tau simultaneously or sequentially. Since high antibody titers are required for AD vaccine efficacy, we have decided to generate vaccines, targeting Aß (AV-1959R), Tau (AV-1980R) or Aß/tau (AV-1953R) B cell epitopes, based on immunogenic MultiTEP platform and evaluate the immunogenicity of these vaccines formulated with Advax(CpG), delta inulin, Alhydrogel(®), Montanide-ISA51, Montanide-ISA720, MPLA-SM pharmaceutical grade adjuvants. Formulation of AV-1959R in Advax(CpG) induced the highest cellular and humoral immune responses in mice. The dual-epitope vaccine, AV-1953R, or the combination of AV-1959R and AV-1980R vaccines formulated with Advax(CpG) induced robust antibody responses against various forms of both, Aß and tau pathological molecules. While anti-Aß antibody titers after AV-1953R immunization were similar to that in mice vaccinated with AV-1959R or AV-1959R/AV-1980R combination, anti-tau titers were significantly lower after AV-1953R injection when compared to the AV-1980R or AV-1959R/AV-1980R. In silico 3D-modeling provided insight into the differences in immunogenicity of these vaccine constructs. In sum, AV-1959R and AV-1980R formulated with Advax(CpG) adjuvant were identified as promising immunogenic vaccines for ongoing pre-clinical assessment and future human clinical trials.

A fresh perspective from immunologists and vaccine researchers: active vaccination strategies to prevent and reverse Alzheimer's disease.

Traditional vaccination against infectious diseases relies on generation of cellular and humoral immune responses that act to protect the host from overt disease even though they do not induce sterilizing immunity. More recently, attempts have been made with mixed success to generate therapeutic vaccines against a wide range of noninfectious diseases including neurodegenerative disorders. After the exciting first report of successful vaccine prevention of progression of an Alzheimer's disease (AD) animal model in 1999, various epitope-based vaccines targeting amyloid beta (Aß) have proceeded to human clinical trials, with varied results. More recently, AD vaccines based on tau protein have advanced into clinical testing too. This review seeks to put perspective to the mixed results obtained so far in clinical trials of AD vaccines and discusses the many pitfalls and misconceptions encountered on the path to a successful AD vaccine, including better standardization of immunologic efficacy measures of antibodies, immunogenicity of platform/carrier and adjuvants.

A dual vaccine against influenza & Alzheimer's disease failed to enhance anti-ß-amyloid antibody responses in mice with pre-existing virus specific memory.

Novel dual vaccine, WSN-Aß(1-10), based on the recombinant influenza virus, expressing immunodominant B-cell epitope of ß-amyloid, simultaneously induced therapeutically potent anti-Aß and anti-influenza antibodies. In this study we showed that boosting of WSN-WT primed mice with WSN-Aß(1-10) enhances anti-viral, but fails to induce anti-Aß antibody responses. This inhibition is associated with expression of Aß(1-10) within the context of an inactivated influenza virus vaccine. These results demonstrate that the use of an inactivated influenza virus as a carrier for AD vaccine may not be applicable due to the possible inhibition of anti-Aß antibody response in individuals previously vaccinated or infected with influenza.

Targeting TLR-4 with a novel pharmaceutical grade plant derived agonist, Immunomax®, as a therapeutic strategy for metastatic breast cancer.

BACKGROUND: Previously we demonstrated that the resection of primary 4T1 tumors only slightly prolongs mouse survival, but importantly, creates a "window of opportunity" with attenuated suppressor cell and increased activated T cell populations. This suggests that additional activation of the immune system by immunostimulatory agents during this period may enhance anti-tumor immunity and potentially eradicate micro-metastatic disease in this stringent model. We hypothesized that the immunostimulator Immunomax®, which is comprised of a plant-derived polysaccharide, is non-toxic in humans and stimulates immune defense during the infectious diseases treatment, may have also anti-tumor activity and be beneficial in the adjuvant setting when endogenous anti-tumor responses are present and during the "window of opportunity" in post-resection metastatic breast cancer model. Here we provide the initial report that Immunomax® demonstrates the capacity to eliminate micro-metastatic disease in the post-resection, 4T1 mouse model of breast cancer. METHODS: The efficacy of Immunomax® was evaluated by analyzing survival rate and the number of spontaneous clonogenic tumor cells in the lung homogenates of mice. The frequencies of activated NK, CD4(+) and CD8(+) cells as well as myeloid-derived suppressor cells and Treg cells were evaluated using flow cytometry. Highly purified mouse and human dendritic and NK cells were sorted and the effect of Immunomax® on activation status of these cells was assessed by flow cytometry. The property of Immunomax® as TLR-4 agonist was determined by NF-κB/SEAP reporter gene assay, WB, RT-PCR. RESULTS: Immunomax® injections significantly prolonged overall survival and cured 31% of mice. This immunostimulator activates DCs via the TLR-4, which in turn stimulates tumoricidal NK cells and in vitro, completely inhibits growth of 4T1 cells. Incubation of PBMC from healthy donors with Immunomax® activates NK cells via activation of plasmacytoid DC leading significantly higher efficacy in killing of human NK-target cells K562 compared with non-treated cells. CONCLUSION: This is the first demonstration that Immunomax® is a TLR-4 agonist and the first report of a documented role for this pharmaceutical grade immunostimulator in augmenting anti-tumor activity, suggesting that incorporation of Immunomax® into developing breast cancer therapeutic strategies may be beneficial and with less potential toxicity than checkpoint inhibitors.

BTX AgilePulse(TM) system is an effective electroporation device for intramuscular and intradermal delivery of DNA vaccine.

DNA vaccines promote immune system activation in small animals and exhibit certain advantages when compared to conventional recombinant protein vaccines. However in clinical trials DNA vaccines are less effective in inducing potent immune responses due to the low delivery efficiency and expression of antigens. Currently, various delivery devices such as gene-guns, bioinjectors and electroporation systems are being used in order to increase the potency of DNA vaccines. However, the optimal delivery parameters are required and must be carefully set to obtain the highest levels of gene expression and strong immune responses in humans. The focus of this study was to optimize electroporation settings (voltage, pulse length, pulse intervals, and number of pulses), as well as the route of administration (intradermal vs. intramuscular) and dosage of the DNA epitope vaccine, AV-1959D, delivered by the BTX AgilePulse(TM) system. As a result, we have chosen the optimal settings for electroporation delivery using different routes of immunization with this vaccine, generating (i) robust antibody production to the B cell epitope (a small peptide, derived from ß-amyloid), and (ii) strong cellular immune responses to Th epitopes (a small synthetic peptide and eleven peptides from various pathogens) incorporated into DNA vaccine platform.

The MultiTEP platform-based Alzheimer's disease epitope vaccine activates a broad repertoire of T helper cells in nonhuman primates.

BACKGROUND: As a prelude to clinical trials we have characterized B- and T-cell immune responses in macaques to AD vaccine candidates: AV-1955 and its slightly modified version, AV-1959 (with 3 additional promiscuous Th epitopes). METHODS: T- and B-cell epitope mapping was performed using the ELISPOT assay and competition ELISA, respectively. RESULTS: AV-1955 and AV-1959 did not stimulate potentially harmful autoreactive T cells, but instead activated a broad but individualized repertoire of Th cells specific to the MultiTEP platform in macaques. Although both vaccines induced robust anti-Aß antibody responses without producing antibodies specific to Th epitopes of MultiTEP platforms, analyses of cellular immune responses in macaques demonstrated that the addition of Th epitopes in the case of AV-1959 created a more potent, superior vaccine. CONCLUSION: AV-1959 is a promising vaccine candidate capable of producing therapeutically potent anti-amyloid antibody in a broader population of vaccinated subjects with high MHC class II gene polymorphisms.