The twenty-four KDa C-terminal tau fragment increases with aging in tauopathy mice: implications of prion-like properties.

The truncated tau protein is a component of the neurofibrillary tangles found in the brains with tauopathies. However, the molecular mechanisms by which the truncated tau fragment causes neurodegeneration remain unknown. Tau pathology was recently suggested to spread through intercellular propagation, and required the formation of 'prion-like' species. We herein identified a new fragment of the tau protein that consisted of four binding domains and a C-terminal tail (Tau-CTF24), but lacked the N-terminal projection domain, and found that it increased with aging in tauopathy model mice (Tg601). Tau-CTF24-like fragments were also present in human brains with tauopathies. A mass spectroscopic analysis revealed that Tau-CTF24 was cleaved behind R242. The digestion of full-length tau (Tau-FL) by calpain produced Tau-CTF24 in vitro and calpain activity increased in old Tg601. Recombinant Tau-CTF24 accelerated heparin-induced aggregation and lost the ability to promote microtubule assembly. When insoluble tau from diseased brains or aggregated recombinant tau was introduced as seeds into SH-SY5Y cells, a larger amount of insoluble tau was formed in cells overexpressing Tau-CTF24 than in those overexpressing Tau-FL. Furthermore, lysates containing the Tau-CTF24 inclusion propagated to naive tau-expressing cells more efficiently than those containing the Tau-FL inclusion. Immunoblot and confocal microscopic analyses revealed that aggregated Tau-CTF24 bound to cells more rapidly and abundantly than aggregated Tau-FL. Our results suggest that Tau-CTF24 contributes to neurodegeneration by enhancing prion-like propagation as well as deteriorating the mechanisms involved in microtubule function.

[Immunotherapy for Alzheimer's disease targeting Aß].

Active and passive immunization of Alzheimer model mice with Aß showed clearance of aggregated amyloid ß deposits and improved memory and learning. Although human trial was halted because of autoimmune encephalitis, the trial revealed that immunization with Aß also deleted amyloid deposits in humans without clinical benefit. On these proof of concept, several clinical trials using monoclonal antibodies are on-going. Although solanezumab which recognizes Aß monomer turned out ineffective in the primary endpoint, it showed significant beneficial effect in mild AD cases in the secondary outcome. Solanezumab is now on a large scale phase III trial in mild AD cases in the world. If it turns out to be effective, it will be the first disease modifying drug for AD in a few years. However, since monoclonal antibodies are extremely expensive, less expensive and long acting active immunization will be widely accepted. More effective and sophisticated vaccines such as DNA vaccine and recombinant viral vaccines will be utilized in future.

Japanese Huperzia serrata extract and the constituent, huperzine A, ameliorate the scopolamine-induced cognitive impairment in mice.

Huperzia serrata has been used as a Chinese folk medicine for many years. It contains huperzine A, which has a protective effect against memory deficits in animal models; however, it is unclear if H. serrata extract exerts any effects in Alzheimer's disease (AD) models. We used H. serrata collected in Japan and determined its huperzine A content using HPLC. We determined its inhibitory effects on acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity. H. serrata extract (30 mg/kg/day) and donepezil (10 mg/kg/day) were orally administrated for 7 days. After repeated administration, we performed the Y-maze and passive avoidance tests. H. serrata extract contained 0.5% huperzine A; H. serrata extract inhibited AChE, but not BuChE. H. serrata extract ameliorated cognitive function in mice. These results indicate that Japanese H. serrata extract ameliorates cognitive function deficits by inhibiting AChE. Therefore, H. serrata extract may be valuable for the prevention or treatment of dementia in AD.

Juzen-Taiho-to, an herbal medicine, promotes the differentiation of transplanted bone marrow cells into microglia in the mouse brain injected with fibrillar amyloid ß.

Microglia are the main immunocompetent and phagocytic cells in Alzheimer's disease (AD). Bone marrow-derived microglia have been demonstrated to be more effective in antigen presentation and phagocytosis than inherent microglia in AD. Thus, microglia have received much attention in the pathogenesis of AD. The herbal medicine Juzen-taiho-to (JTT) has been reported to reduce ß-amyloid (Aß) burden in the mouse brain of an AD model. In this study, we explored the effects of JTT on the migration and differentiation of bone marrow-derived cells in the mouse brain of acutely induced AD. To chase bone marrow-derived cells, we made a chimeric mouse line in C57BL/6 by transplanting fresh bone marrow cells, isolated from the transgenic mice expressing enhanced green fluorescent protein gene. The chimeric mice were orally administrated with JTT or distilled water, and were left untreated or given intrahippocampal injection of fibrillar Aß 1-42 (fAß42) or vehicle. In the hippocampus of the vehicle-injected mouse, JTT treatment for 37 days caused a significant increase in the number of microglial cells. In the fAß42-injected mouse hippocampus, a larger number of bone marrow-derived cells were detected in JTT-treated mice than control mice in the non-neighboring regions of the fAß42-injected site but not around the injected site. These results suggest that JTT might contribute to the reduction of Aß burden and the immune surveillance in non-pathological as well as pathological brain regions. The results also implicate the therapeutic potential of JTT in AD.

Sendai virus vector-mediated brain-derived neurotrophic factor expression ameliorates memory deficits and synaptic degeneration in a transgenic mouse model of Alzheimer's disease.

Growing evidence suggests that decreased brain-derived neurotrophic factor (BDNF) levels are associated with Alzheimer's disease (AD) pathogenesis. Therefore, BDNF gene therapy is considered to be a promising therapeutic strategy for treating AD. Sendai virus (SeV) is a type I parainfluenza virus that does not interact with host chromosomes because of its strict cytoplasmic life cycle. Although SeV is nonpathogenic in primates, including humans, its infectivity for neurons is strong. Here we demonstrate that SeV vectors effectively infected neurons, even though they were injected into subcortical white matter. Moreover, SeV vectors significantly induced BDNF expression, ameliorating synaptic degeneration and memory deficits in a transgenic mouse model of AD (Tg2576). This is the first study to demonstrate that viral vector administration in white matter is sufficient to restore cognitive function in vivo. These results also support the feasibility of using SeV vectors for gene therapy targeting the brain.

Apomorphine treatment in Alzheimer mice promoting amyloid-ß degradation.

OBJECTIVE: Intracellular amyloid ß-protein (Aß) contributes to neurodegeneration in Alzheimer disease (AD). Apomorphine (APO) is a dopamine receptor agonist for Parkinson disease and also protects against oxidative stress. Efficacy of APO for an AD mouse model and effects of APO on cell cultures are studied. METHODS: The triple transgenic AD mouse model (3xTg-AD) has 2 familial AD-related gene mutations (APP(KM670/671NL) /PS1(M146V)) and a tau gene mutation (Tau(P301L)). Six-month-old 3xTg-AD mice were treated with subcutaneous injections of APO once a week for 1 month. Memory function was evaluated by Morris water maze before and after the treatment. Brain tissues were examined by immunohistochemical staining and Western blotting. Effects of APO on intracellular Aß degradation, activity of Aß-degrading enzymes, and protection against oxidative stress were studied in cultured SH-SY5Y cells. RESULTS: After APO treatment, short-term memory function was dramatically improved. Significant decreases in the levels of intraneuronal Aß, hyper-phosphorylated tau (p-tau), p53, and heme oxygenase-1 proteins were observed. Moreover, APO promoted degradation of intracellular Aß, increased activity of proteasome and insulin-degrading enzyme, protected against H(2) O(2) toxicity, and decreased p53 protein levels in the cultured cells. INTERPRETATION: 3xTg-AD mice show intraneuronal Aß accumulation and memory disturbances before extracellular Aß deposition. Our data demonstrating improvement of memory function of 3xTg-AD mice with decreases in intraneuronal Aß and p-tau levels by APO treatment strongly suggest that intraneuronal Aß is an important therapeutic target and APO will be a novel drug for AD.

Extensive loss of connexins in Baló's disease: evidence for an auto-antibody-independent astrocytopathy via impaired astrocyte-oligodendrocyte/myelin interaction.

Extensive aquaporin-4 (AQP4) loss without perivascular deposition of either activated complement or immunoglobulins is a characteristic of Baló's disease. Our aim in this study was to investigate the relationship between astrocytopathy and demyelination in Baló's disease, focusing on connexins (Cx), which form gap junctions among glial cells and myelin. Autopsied specimens from four cases that provided seven actively demyelinating concentric lesions infiltrated with numerous CD68(+) macrophages were immunohistochemically examined for the astrocyte markers glial fibrillary acidic protein (GFAP), AQP4, Cx43, Cx30 and megalencephalic leukoencephalopathy with subcortical cyst 1 (MLC1). Specimens were also stained for oligodendrocyte/myelin markers, namely Cx32, Cx47, myelin-associated glycoprotein (MAG), myelin oligodendrocyte glycoprotein (MOG), oligodendrocyte-specific protein (OSP) and Nogo-A. Serum samples from six patients that had undergone magnetic resonance imaging, confirming a diagnosis of Baló's disease, were assayed for the presence of anti-Cx43, -Cx32 and -AQP4 antibodies. Despite the presence of numerous GFAP- and MLC1-positive astrocytes, there was a marked decrease in the levels of Cx43, Cx32 and Cx47. At the leading edges, Cx43 and AQP4 were mostly absent despite positive GFAP, MLC1, Cx32, Cx47, MOG, MAG, and OSP immunoreactivity. Of the six Baló's disease patients, none were positive for anti-Cxs or -AQP4 antibodies. Baló's disease is characterized by extensive loss of Cxs and AQP4, and a lack of auto-antibodies to Cxs and AQP4. Loss of Cx43 and AQP4 in the presence of other oligodendrocyte/myelin proteins at the leading edges suggests the possibility that auto-antibody-independent astrocytopathy may contribute to disease pathology via the disruption of astrocyte-oligodendrocyte/myelin interactions.

Long-term oral intake of aluminium or zinc does not accelerate Alzheimer pathology in AßPP and AßPP/tau transgenic mice.

Whether or not the oral intake of metals such as aluminium (Al) and zinc (Zn) is a risk for Alzheimer's disease (AD) has been a matter of controversy. Lack of AD pathology in patients with Al encephalopathy indicates Al does not cause AD. On the other hand, some epidemiological studies have suggested high Al increases the occurrence of AD. Our purpose is to test if high Al in drinking water is a risk factor for AD. We administered Al and Zn in drinking water to Tg2576, a transgenic mouse model for amyloid ß-protein (Aß) deposition with the Aß precursor protein (AßPP) mutations (K670N/M671L), and Tg2576/tau(P301L), a model for Aß and tau deposition. Deionized water was given to the control Tg2576 and Tg2576/tau. After administration for 4-10 months of approximately 100 mg/kg body weight Al or Zn per day, we were not able to find by quantitative immunohistochemical analyses differences in the deposition of Aß and tau between the treated and untreated groups. Nor did the Al or Zn treatment affect the amount of soluble Aß and Aß*56, an Aß oligomer, measured by ELISA or immunoblot. The oral intake of excess Al or Zn does not accelerate AD pathology in the transgenic mouse models for Aß and tau accumulation. Such results do not seem to support the notion that excessive oral intake of Al or Zn is a risk factor for AD.

[Current trend of immunotherapy for Alzheimer's disease].

Immunotherapy targeting amyloidbeta (Abeta) for Alzheimer's disease (AD) has been developed based on the amyloid cascade hypothesis. It was shown that active immunization using Abeta peptide attenuates amyloid deposits and memory impairment in AD model mice. However, active immunization of patients with AD (AN1792) was halted because 6 % of patients developed meningoencephalitis. Follow-up studies demonstrated that AN1792 could not improve cognitive functions, although senile plaques were cleared. These results suggest that active immunization is a valid strategy and bring us a new perspective. It is speculated that the next generation immunotherapy should activate humoral immunity but not cellular immunity. Recently, there are a lot of immunization strategies for AD. Here we introduce a current trend of immunotherapy for AD.

Aquaporin-4 astrocytopathy in Baló's disease.

Baló's concentric sclerosis (BCS) is considered to be a rare variant of multiple sclerosis and characterized by alternating rings of demyelinated and preserved myelin layers. The mechanism underlying BCS remains to be elucidated. Recently, occurrence of concentric rings of Baló was described in the brainstem of a patient with neuromyelitis optica (NMO). Because selective loss of aquaporin-4 (AQP4) and vasculocentric deposition of complement and immunoglobulins are characteristic in NMO, we aimed to assess AQP4 expression in the concentric demyelinating lesions of BCS patients. We evaluated AQP4 expression relative to expression of another astrocytic marker (glial fibrillary acidic protein), the extent of demyelination, lesion staging and perivascular deposition of complement and immunoglobulin in four cases with BCS, and 30 individuals with other neurological diseases. All cases with BCS demonstrated extensive AQP4 loss in both demyelinated and myelinated layers of all actively demyelinating lesions, with perivascular lymphocytic cuffing of T cells, but no deposition of immunoglobulins or complement around vessels. These findings suggest that AQP4 loss occurs in heterogeneous demyelinating conditions, namely NMO and BCS. Furthermore, acute BCS lesions are characterized by extensive AQP4 loss without vasculocentric deposition of complement or immunoglobulin.

Immunization therapy for Alzheimer disease: a comprehensive review of active immunization strategies.

Based on the amyloid cascade hypothesis, various strategies targeting amyloid beta protein (Abeta) have been invented for prevention and treatment of Alzheimer disease (AD). Active and passive immunizations with Abeta and Abeta antibodies successfully reduced AD pathology and improved cognitive functions in an AD mouse model. However, active immunization with AN-1792, a mixture of Abeta1-42 peptide and adjuvant QS21 induced autoimmune encephalitis in humans. Surprisingly, although AN-1792 cleared senile plaque amyloid, it showed no benefit in humans. It is speculated that AN-1792 failed in deleting more toxic forms of Abeta such as oligomers and intracellular Abeta, suggesting that newly developing vaccines should delete these toxic molecules. Since T cell epitopes exist mainly in the C-terminal portion of Abeta, vaccines using shorter N-terminal peptides are under development. In addition, since T helper 1 (Th1) immune responses activate encephalitogenic T cells and induce continuous inflammation in the central nervous system, vaccines inducing Th2 immune responses seem to be more promising. These are N-terminal short Abeta peptides with Th2 adjuvant or Th2-stimulating molecules, DNA vaccines, recombinant viral vector vaccines, recombinant vegetables and others. Improvement of vaccines will be also achieved by the administration method, because Th2 immune responses are mainly induced by mucosal or trans-cutaneous immunizations. Here I review recent progress in active immunization strategies for AD.

Effects of Ferulic Acid and Angelica archangelica Extract (Feru-guard ®) on Mild Cognitive Impairment: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Prospective Trial.

We conducted a multicenter, randomized, double-blind, placebo-controlled prospective trial examining a supplement containing ferulic acid and Angelica archangelica extract (Feru-guard ®) for mild cognitive impairment (MCI). In the intention-to-treat population, Mini-Mental State Examination (MMSE) scores were significantly better at 24 weeks (p = 0.041) in the active group. In the per protocol population, MMSE was significantly better in the active group at 24 weeks (p = 0.008), and mixed effect models for repeated measures (MMRM) showed significant difference (p = 0.016). ADAS-Jcog was significantly better at 24 (p = 0.035) and 48 weeks (p = 0.015) in the active group, and MMRM was significant (p = 0.031). Thus, Feru-guard ® may be useful for MCI.

Homocysteic Acid in Blood Can Detect Mild Cognitive Impairment: A Preliminary Study.

BACKGROUND: In the treatment of Alzheimer's disease (AD), it is thought to be most effective to intervene at the earliest and mildest stages. For diagnosis at the earliest and mildest stages, it is desirable to use a biomarker that can be detected by a minimally invasive, cost-effective technique. Recent research indicates the potential clinical usefulness of plasma amyloid-ß (Aß) biomarkers in predicting brain Aß burden at an individual level. However, it is as yet unproven that accumulation of Aß necessarily leads to the development of AD. OBJECTIVE: Homocysteic acid (HCA) is useful as an early diagnostic marker for mild cognitive impairment (MCI), a pre-stage of AD. METHODS: We measured the concentration of HCA, tumor necrosis factor alpha, cortisol, tau, and phosphorylated tau (p-tau) in patients' plasma of 22 AD, 23 MCI, and 9 negative control (NC) cases. RESULTS: Plasma HCA was shown to be very high in areas under the receiver operating characteristic curves (AUC), distinguished between MCI and NC; when 0.116µM was chosen as the analyte concentration cut-off, the sensitivity was 95.7% and the specificity was 70%. CONCLUSION: Our results suggest that plasma HCA may be a useful indicator as an early diagnostic marker for MCI. HCA seems to be upstream from neurodegeneration in the AD pathology because it is known that an overactive NMDA receptor promotes amyloid polymerization and tau phosphorylation in AD.

Distinct microglial and macrophage distribution patterns in the concentric and lamellar lesions in Baló's disease and neuromyelitis optica spectrum disorders.

TMEM119 and purinergic receptor P2Y12 (P2RY12), which are not expressed by recruited peripheral blood macrophages, are proposed to discriminate microglia from macrophages. Therefore, we investigated the distribution patterns of microglia and macrophages in 10 concentric lesions from four autopsied Baló's disease cases and one neuromyelitis optica spectrum disorder (NMOSD) case, using quantitative immunohistochemistry for the markers TMEM119, P2RY12, CD68, CD163 and GLUT5. Three cases with Baló's disease had distal oligodendrogliopathy (DO) showing preferential loss of myelin-associated glycoprotein and early active demyelination in the outermost demyelinating layer (termed DMY-MO). In DMY-MO with DO, TMEM119-positive activated microglia expressing upregulated GLUT5 but markedly downregulated P2RY12 were significantly increased. These activated microglia expressed inducible nitric oxide synthase. Oligodendrocytes and their precursors showed apoptotic-like nuclear condensation in DMY-MO. TMEM119-negative and CD68/CD163-positive macrophages were distributed throughout the lesion center of DMY-MO with DO and these cells demonstrated foamy morphology only in the inner portion but not in the outer portion. In concentric demyelinating lesions from another Baló's case and lamellar demyelinating lesions in an NMOSD case, which had late active demyelination without DO, the densities of TMEM119-, GLUT5- and P2RY12-positive microglia with ramified morphology were significantly increased in myelinated layers but not in demyelinating layers. In particular, in the NMOSD case, TMEM119-positive microglia were confined to the outer portion of the myelinated layers. CD68-positive macrophages with foamy morphology also expressing CD163 accumulated in myelinated as well as in demyelinated layers. These findings suggest that activated microglia expressing TMEM119 and GLUT5, but not P2RY12, are associated with apoptosis of oligodendrocytes in the leading edge of Baló's concentric lesions with DO, whereas TMEM119-, GLUT5- and P2RY12-positive microglia with ramified morphology are associated with myelin preservation in concentric lesions without DO in Baló's disease and NMOSD. These two types of microglia appear to play distinct roles in the formation of concentric lesions.

Nasal vaccine delivery attenuates brain pathology and cognitive impairment in tauopathy model mice.

Pathological aggregates of tau proteins accumulate in the brains of neurodegenerative tauopathies including Alzheimer's disease and frontotemporal lobar degeneration (FTLD-tau). Although immunotherapies of these disorders against tau are emerging, it is unknown whether nasal delivery, which offers many benefits over traditional approaches to vaccine administration, is effective or not for tauopathy. Here, we developed vaccination against a secreted form of pathological tau linked to FTLD-tau using a Sendai virus (SeV) vector infectious to host nasal mucosa, a key part of the immune system. Tau vaccines given as nasal drops induced tissue tau-immunoreactive antibody production and ameliorated cognitive impairment in FTLD-tau model mice. In vivo imaging and postmortem neuropathological assays demonstrated the suppression of phosphorylated tau accumulation, neurotoxic gliosis, and neuronal loss in the hippocampus of immunized mice. These findings suggest that nasal vaccine delivery may provide a therapeutic opportunity for a broad range of populations with human tauopathy.

Enhancement of activation of caspases by presenilin 1 gene mutations and its inhibition by secretase inhibitors.

Presenilin 1 (PS1) gene mutations are the major causes of early-onset familial Alzheimer's disease. Acceleration of apoptosis is one of the major pathogenic mechanisms of PS1 mutants, and PS1 mutants have also been reported to induce overproduction of amyloid-beta protein 42. Here, we investigated aberrancy in activation of initiator caspases related to two PS1 gene mutations, I143T and G384A. Acceleration of apoptosis, elevation of caspase-3/7 activity, and significant increases in caspase-4, -8 and -9 activities during apoptosis induced by several agents were found in these mutant PS1-transfected cells. Interestingly, thapsigargin treatment enhanced caspase-4 and -9 activities in I143T-mutant PS1-transfected cells, while hydrogen peroxide treatment enhanced caspase-4, -8 and -9 activities in G384A-mutant PS1-transfected cells, indicating diverse apoptosis-promoting effects of PS1 gene mutations. In addition, treatment with a beta-secretase inhibitor or gamma-secretase inhibitor significantly attenuated the effects of the PS1 mutants on caspase-3/7 activation and recovered cell viability. Our present data suggest that these PS1 mutants accelerate the activation of initiator caspases and promote apoptosis, which may be associated, at least in part, with amyloid-beta production.

Increase in p53 protein levels by presenilin 1 gene mutations and its inhibition by secretase inhibitors.

Presenilin 1 (PS1) gene mutations are the major causes of early-onset familial Alzheimer's disease and are known to increase amyloid-beta42 (Abeta42) production as well as to promote apoptosis. We have recently reported that intracellular Abeta42 activates p53 mRNA expression and promotes p53-dependent apoptosis. Here, we examined the p53 mRNA and protein levels in cells transfected with wild-type and I143T/G384A mutant PS1 genes. Although the baseline p53 mRNA levels remained unaltered, the p53 protein levels were significantly elevated in mutant PS1-transfected cells. Treatments with apoptosis-inducing agents induced significant elevation of the p53 protein but not p53 mRNA levels in mutant PS1-transfected cells. Treatment with a beta-secretase inhibitor and gamma-secretase inhibitor decreased the intracellular Abeta levels in amyloid-beta protein precursor (AbetaPP) and PS1-double transfected cells, and restrained upregulation of the p53 protein levels in the mutant PS1-transfected cells. Also, we found that proteasome activity was decreased in mutant PS1-transfected cells compared to wild-type PS1-transfected cells. Proteasome activity was further decreased in AbetaPP/PS1-double transfected cells. Taken together, p53-dependent apoptosis upregulated by the I143T/G384A mutant PS1 gene may be associated, at least in part, with intracellular Abeta and proteasome impairment.

A family of membrane proteins associated with presenilin expression and gamma-secretase function.

Presenilin 1 (PS1) forms the gamma-secretase complex with at least three components: nicastrin, APH-1, and PEN-2. This complex mediates intramembrane cleavage of amyloid precursor protein (APP) to generate beta-amyloid protein (Abeta) as well as other type 1 transmembrane proteins. Although PS1 mutations linked to familial Alzheimer's disease influence these cleavages, their biological consequences have not been fully understood. In this study, we used mRNA differential display analysis to identify a gene, denoted adoplin-1/ORMDL-1, which displays significantly reduced expression in association with PS1 mutations. Adoplin-1 and two highly homologous genes (adoplin-2, -3) constitute a gene family that encodes transmembrane proteins. The mRNA and protein levels of adoplins (particularly adoplin-1, -2) were markedly elevated in PS-deficient fibroblasts, compared to wild-type cells. Moreover, knockdown of the three adoplins by RNA interference affected maturation of nicastrin and its association with PS1. Adoplin knockdown additionally resulted in elevated levels of APP C-terminal fragments and decreased Abeta production, suggestive of reduced gamma-secretase activity. Our data collectively indicate that adoplins are unique molecules with PS-related expression and functions that may play important role(s) in the maturation and activity of the gamma-secretase complex.

[Vaccination therapy for Alzheimer's disease].

Since AN-1792 vaccine induced autoimmune encephalitis, several pharmaceutical companies are now concentrated in developing antibody therapy in Alzheimer's disease (AD). Each antibody has own characteristics. Thus, it is unpredictable at present which antibody is the most beneficial until we see the result of clinical trials. If disease modifying antibodies were found, they will be widely used for treatment of AD in near future. As a candidate of such antibodies, we have developed TAPIR-like antibody with much higher affinity to Abeta42 than Abeta40, and it effectively deleted senile plaque amyloid and Abeta oligomers without increasing microhemorrhages. Although passive immunization can avoid autoimmune encephalitis, it is expensive and it is not suitable for prevention. Thus, safe vaccines by active immunization would be better. Vaccines that induce Th2 type immune responses such as oral vaccine or per-nasal vaccine would be promising.

Development and characterization of a TAPIR-like mouse monoclonal antibody to amyloid-beta.

Tissue amyloid plaque immuno-reactive (TAPIR) antibody was better related to the effect of immunotherapy in Alzheimer's disease (AD) than ELISA antibody. Here we used a hybridoma technique to develop a TAPIR-like anti-human amyloid-beta (Abeta) mouse monoclonal antibody. The obtained monoclonal antibody, 3.4A10, was an IgG2b isotype and recognized N-terminal portion of Abeta1-42 without binding denatured or native amyloid-beta protein precursor. It had higher affinity to Abeta1-42 than to Abeta1-40 by Biacore affinity analysis and stained preferably the peripheral part of senile plaques and recognized the plaque core less than 4G8. It inhibited the Abeta1-42 fibril formation as well as degraded pre-aggregated Abeta1-42 peptide in a thioflavin T fluorescence spectrophotometry assay. The in vivo studies showed that 3.4A10 treatment decreased amyloid burden compared to the control group and significantly reduced Abeta42 levels rather than Abeta40 levels in brain lysates as well as the Abeta*56 oligomer (12mer) in TBS fraction of the brain lysates. 3.4A10 entered brain and decorated some plaques, which is surrounded by more Iba1-positive microglia. 3.4A10 therapy did not induce lymphocytic infiltration and obvious increase in microhemorrhage. We conclude that 3.4A10 is a TAPIR-like anti-human amyloid monoclonal antibody, and has a potential of therapeutic application for AD.