ABSTRACT
The amyloid-ß (Aß) oligomer, rather than the Aß monomer, is considered to be the primary initiator of Alzheimer's disease. It was hypothesized that p(Aß3-10)10-MT, the recombinant Aß3-10 gene vaccine of the Aß oligomer has the potential to treat Alzheimer's disease. In this study, we intramuscularly injected the p(Aß3-10)10-MT vaccine into the left hindlimb of APP/PS1/tau triple-transgenic mice, which are a model for Alzheimer's disease. Our results showed that the p(Aß3-10)10-MT vaccine effectively reduced Aß oligomer levels and plaque deposition in the cerebral cortex and hippocampus, decreased the levels tau protein variants, reduced synaptic loss, protected synaptic function, reduced neuron loss, and ameliorated memory impairment without causing any cerebral hemorrhaging. Therefore, this novel DNA vaccine, which is safe and highly effective in mouse models of Alzheimer's disease, holds a lot of promise for the treatment of Alzheimer's disease in humans.
ABSTRACT
The aggregation of amyloid ß-peptide (Aß) is thought to play a pivotal role in the disease progression of Alzheimer's disease (AD). Amyloid ß directed immunotherapy has been considered an alternative AD treatment. In this study, we constructed a DNA vaccine, p(Aß3-10)10-mIL-4, encoding ten tandem repeats of Aß3-10 fused with mouse IL-4. Eight-month-old APP/PS1 transgenic mice were injected intramuscularly with p(Aß3-10)10-mIL-4 followed by in vivo electroporation. Immunization with the vaccine induced high-titer anti-Aß antibodies and attenuated the behavior impairment. Immunoglobulin isotyping revealed a predominantly IgG1 response and ex vivo cultured splenocytes exhibited a low IFN-γ and high IL-4 response, indicating a Th2 anti-inflammatory response. Immunohistochemical analysis revealed that p(Aß3-10)10-mIL-4 immunization decreased Aß deposition, and the microglial attraction significantly decreased accompanied by the clearance of Aß. There was no microhemorrhage in the brain of the immunized mice. These results suggest that the immunization potentially reduced the inflammation in brain of transgenic mice and therefore improved their cognitive ability. This novel DNA vaccine p(Aß3-10)10-mIL-4 may be an effective immunization method as therapy for AD.
Subject(s)
Amyloid beta-Protein Precursor , Cerebral Cortex/drug effects , Cognition Disorders/drug therapy , Electrochemotherapy/methods , Presenilin-1 , Vaccination/methods , Vaccines, DNA/administration & dosage , Amyloid beta-Protein Precursor/genetics , Animals , Cerebral Cortex/pathology , Cognition Disorders/genetics , Cognition Disorders/pathology , Female , HEK293 Cells , Humans , Inflammation/drug therapy , Inflammation/genetics , Mice , Mice, Transgenic , Presenilin-1/geneticsABSTRACT
Immunization of AD mouse models with Aß reduced Aß deposits and improved memory and learning deficits, but some clinical trials of immunization with Aß were halted due to brain inflammation which was presumably induced by a T cell-mediated autoimmune response. We have developed a "possibly safer" vaccine. Our results demonstrate that pcDNA3.1 vector encoding ten repeats of Aß3-10 fragments elicited high titers of antibodies which reacted well with not only monomeric but also oligomeric and fibrillar forms of Aß42 peptide. Induced antibodies strongly reacted with amyloid plaques in the brain, demonstrating functional activity of the antibodies. Immunohistochemical and immunofluorescence showed there was significantly less plaque deposition accomplied with less microglia activation as detected both in the frontal cortex and hippocampus. These data suggested that microglial activation is necessary for efficient removal of compact amyloid deposits with immunotherapy. No obvious inflammation T cell and Prussian blue positive cell was found indicated that inflammation T cell infiltration and microhemmorage can be avoided or at least reduced to the minimum level.
Subject(s)
Amyloid beta-Peptides/pharmacology , Encephalitis/therapy , Immunotherapy, Active/methods , Microglia/immunology , Peptide Fragments/pharmacology , Plaque, Amyloid/therapy , Vaccines, DNA/pharmacology , Alzheimer Disease/immunology , Alzheimer Disease/therapy , Amyloid beta-Peptides/immunology , Animals , Central Nervous System/cytology , Central Nervous System/immunology , Cerebral Hemorrhage/immunology , Cerebral Hemorrhage/therapy , Disease Models, Animal , Encephalitis/immunology , Mice , Mice, Transgenic , Peptide Fragments/immunology , Plaque, Amyloid/immunology , Random Allocation , T-Lymphocytes/immunology , Vaccines, DNA/immunologyABSTRACT
To develop a safe and efficient vaccine for AD treatment, we constructed an adenovirus vector vaccine encoding ten repeats of Aß3-10 and CpG motif as a molecular adjuvant. We demonstrated that therapeutic immunization with Ad-10×Aß3-10-CpG elicits Aß3-10 specific Th2-polarized immune response with high titers of anti-Aß antibodies in APPswe/PSEN1dE9 mice, which in turn reduced Aß deposits in brains and cognitive impairment. In addition, Ad-10×Aß3-10-CpG reduced astrocytosis without increasing the incidence of microhemorrhage. Our findings of this study raise the possibility that the adenovirus vaccine Ad-10×Aß3-10-CpG would be a safe and effective alternative for AD immunotherapy.
Subject(s)
Alzheimer Disease/drug therapy , Alzheimer Disease/immunology , Alzheimer Vaccines/administration & dosage , Amyloid beta-Peptides/administration & dosage , Amyloid beta-Peptides/immunology , Cognition Disorders/prevention & control , Adenoviridae/genetics , Adjuvants, Immunologic/administration & dosage , Administration, Intranasal , Alzheimer Disease/pathology , Alzheimer Vaccines/immunology , Animals , Brain/immunology , Brain/metabolism , Brain/pathology , Cognition Disorders/etiology , CpG Islands/immunology , Disease Models, Animal , Enzyme-Linked Immunosorbent Assay , Genetic Vectors , Immunohistochemistry , Male , Maze Learning/drug effects , Mice , Mice, Transgenic , Peptide Fragments/immunologyABSTRACT
Active immunization holds great promise for the treatment of Alzheimer's disease but the infiltration of T-lymphocytes and associated meningoencephalitis observed in clinical trials needs to be overcome. To avoid this toxicity, previous studies have used synthetic truncated derivatives of Aß to promote humoral immunity. In this study, we developed a novel vaccine [p(Aß3-10)10-MT] that expresses ten repeats of Aß3-10 with melatonin (MT) as an adjuvant, and administered it intramuscularly in three-month-old Tg-APPswe/PSEN1dE9 (Tg) mice by in vivo electroporation. The p(Aß3-10)10-MT vaccine induced high titers of anti-Aß antibodies, which in turn reduced Aß deposits in the mouse brains and decreased cognitive impairment. Immunoglobulin isotyping revealed a predominantly IgG1 response, indicating a Th2 anti-inflammatory response. Ex vivo cultured splenocytes exhibited a low IFN-γ and high IL-4 response. Immunohistochemical analysis revealed that glial cell activation was also attenuated. These results indicate that p(Aß3-10)10-MT may potentially be an effective vaccine to reduce accumulated Aß and attenuate cognitive deficits.
Subject(s)
Amyloid beta-Peptides/genetics , Cognition Disorders/metabolism , Electroporation , Vaccines, DNA/administration & dosage , Amyloid beta-Peptides/immunology , Animals , Cognition Disorders/genetics , Cytokines/biosynthesis , Enzyme-Linked Immunosorbent Assay , HEK293 Cells , Humans , Maze Learning , Mice , Mice, Transgenic , T-Lymphocytes/immunology , Vaccines, DNA/geneticsABSTRACT
BACKGROUND: Amyloid ß(1-42) (Aß(42)) peptide vaccination has been proved to be effective in reducing amyloid burden in brain and improving cognitive function in Alzheimer's disease (AD) mouse models. But the phase II trial of Aß(42) peptide vaccine was halted because of T cell-mediated meningoencephalitis. In this study, a DNA vaccine, p(Aß(3-10))(10)-CpG, was constructed to test whether it would induce predominant T(H)2 immune response upon immunization of BALB/c mice. METHODS: BALB/c mice were vaccinated intramuscularly with p(Aß(3-10))(10)-CpG plasmids. Aß(42) peptide, pcDNA3.1(+) empty vector and PBS were injected to the control groups. Expression of interesting gene in injected muscle was identified by immunohistochemistry. Anti-Aß antibody titers, isotype profiles as well as cytokines in ex vivo splenocytes culture supernatants were analyzed by enzyme-linked immunosorbent assay (ELISA). RESULTS: P(Aß(3-10))(10)-CpG plasmid was expressed in muscle after injection detected by immunohistochemistry. The p(Aß(3-10))(10)-CpG vaccine induced high titers of anti-Aß antibodies in BALB/c mice. And isotype of the antibodies was mainly IgG1, the IgG1/IgG2a ratio for the p(Aß(3-10))(10)-CpG group was approximately 5 times greater than that for the Aß(42) peptide group. Ex vivo cultured splenocytes isolated from mice immunized with p(Aß(3-10))(10)-CpG exhibited high interleukin-4 response and low interleukin-γ (IFN-γ) response. CONCLUSIONS: Immunization with p(Aß(3-10))(10)-CpG vaccine primarily induces a T(H)2 type of response, thus reduces the probability of inflammation. This p(Aß(3-10))(10)-CpG vaccine possesses the basic factors required for a safe and effective AD vaccine.
Subject(s)
Alzheimer Disease/immunology , Alzheimer Disease/therapy , Amyloid beta-Peptides/immunology , T-Lymphocytes/immunology , Vaccines, DNA/therapeutic use , Animals , Cells, Cultured , Enzyme-Linked Immunosorbent Assay , Immunity, Humoral/immunology , Immunoglobulin G/metabolism , Immunohistochemistry , Interferon-gamma/metabolism , Interleukin-4/metabolism , Mice , Mice, Inbred BALB C , Muscles/metabolismABSTRACT
To develop a safe and efficient vaccine for the treatment of Alzheimer's disease, we constructed a novel adenovirus vaccine encoding ten repeats of Aß3-10 and CpG motif as an adjuvant and investigated the immune response in BALB/c mouse after intranasal inoculation with this vaccine. The Ad-10×Aß3-10-CpG induces an IgG1 predominant humoral response and production of IL-4 and IL-10 in splenocytes in vitro, indicating a Th2-polarized immune response. Stimulation of splenocytes with Aß3-10 peptide induces robust proliferation but not with full-length Aß42 peptide, demonstrating that Ad-10×Aß3-10-CpG does not induces Aß42 specific T cell immune response. The findings raise the possibility that the adenovirus vaccine Ad-10×Aß3-10-CpG could be a safe and effective alternative for immunotherapy in Alzheimer's disease.
Subject(s)
Adenoviridae/immunology , Amyloid beta-Peptides/administration & dosage , Immunity, Cellular , Repetitive Sequences, Amino Acid , Th2 Cells/immunology , Viral Vaccines/administration & dosage , Viral Vaccines/immunology , Adenoviridae/genetics , Administration, Intranasal , Alzheimer Disease/immunology , Alzheimer Disease/pathology , Alzheimer Disease/prevention & control , Amyloid beta-Peptides/genetics , Amyloid beta-Peptides/immunology , Animals , Cell Polarity/genetics , Cell Polarity/immunology , Cells, Cultured , Genetic Vectors/administration & dosage , Genetic Vectors/immunology , Humans , Immunity, Cellular/genetics , Interleukin-10/biosynthesis , Interleukin-4/biosynthesis , Male , Mice , Mice, Inbred BALB C , Mice, Transgenic , Repetitive Sequences, Amino Acid/genetics , Repetitive Sequences, Amino Acid/immunology , Spleen/immunology , Spleen/metabolism , Th2 Cells/virology , Viral Vaccines/geneticsABSTRACT
The present study aimed to investigate the effects of Aß3-10 repeat fragment plasmid for the treatment of Tg-APPswe/PSEN1dE9 (Tg) mice. The plasmid pcDNA3.1-(Aß3-10)10-CpG was constructed and intramuscularly injected into 12-month-old Tg mice. Through the use of behavioral tests, anti-Aß antibody and Aß assays, cytokine assay, Aß deposition, and astrocytes analysis results demonstrated that Aß3-10 repeat fragment plasmid exhibited immunogenicity and reduced memory impairment in Tg mice via clearance of cerebral Aß deposition, without significant side effects. Aß3-10 repeat fragment plasmid immunization reduced Th1 cell-mediated immunity, secretion of interferon-γ, and stimulation to astrocytes. These data showed that the Aß3-10 repeat fragment plasmid improved memory and decreased cognitive impairment in Tg mice by reducing Aß deposition and inflammatory responses.
