CN101318015A - Senile dementia recombinant protein vaccine and preparation method thereof - Google Patents

Abstract

The invention relates to a recombinant multivalent Beta-amyloid 1-15(ABeta1-15) protein vaccine of senile dementia and a preparation method thereof. The proposal is adopted as following: a plurality of oligonucleotide primers are synthesized, two or more than two bivalent ABeta1-15 gene sections containing flexion connection peptide gene are obtained by gene amplification and are cloned into pQE-30 prokaryotic expression plasmid, and inducible expression by bacillus and purification are carried out, thus preparing the folding bivalent ABeta1-15 recombinant protein vaccine which can express flexibility. In the invention, the multivalent folding ABeta1-15 is selected as the immunogen, thus avoiding the spacing rigescent structure of multi-copy ABetaB cell epitope, leading the ABeta1-15 epitope to be exposed easily, and improving immunogenicity. Meanwhile, the molecular weight of immunogenicity is increased, and the possibility of degradation is lowered. The prokaryotic expression system is selected for preparing recombinant protein, thus avoiding the shortcomings of high difficulty and high cost of chemosynthesis.

Description

Senile dementia recombinant protein vaccine and preparation method thereof

Technical field

The present invention relates to a kind of vaccine and preparation method thereof, particularly a kind of alzheimer disease reorganization multivalence amyloid-beta 1-15 (A β _1-15) protein vaccine and preparation method thereof.

Background technology

Alzheimer disease (Alzheimer ' s disease, AD) be a kind of neurocyte degenerative disease, clinical is feature with memory of carrying out property and the forfeiture of acquired knowledge, to the last patient loses viability.Along with the increase of number of the infected, AD brings white elephant for family and society, is an important society and health care problem.About the treatment of AD, still there is not desirable method at present, existing therapeutic strategy mainly is conceived to relief of symptoms, does not stop the pathology process of AD, and its clinical efficacy is unsatisfactory.A β is the main component that alzheimer disease pathology changes senile plaque, and it is made up of 39～42 aminoacid.Studies show that in recent years, the infringement of the neuron that gathers and deposit and follow of A β is the key link of alzheimer disease pathology mechanism, therefore, is suggested in succession at therapeutic strategy and the method for A β.Studies show that, Schenk reported first in 1999 Immunization with amyloid-betaattenuates Alzheimer-disease-like pathology in the PDAPP mouse[seecomments] and .Nature, 1999 Jul 8; 400 (6740): 173-7} adopts immunological method that transgenic AD model mouse (PDAPP Mus) is treated; At present, external alzheimer disease vaccine A β ₄₂Peptide vaccine has entered II a clinical trial, because inoculation back syndrome has appearred in the part test patient, comprises aseptic meningitis, and therefore experiment stops.Postmortem finds in patient's pia mater encephali, vascular space and brain essence the T cellular infiltration to be arranged, infer thus meningoencephalitis generation may with A β ₄₂Toxicity T cell antigen epitope (the A β that full peptide C-terminal contains _16-42) excited body Th1 type autoimmune response relevant.Therefore, the method for preparing second filial generation AD vaccine by the method for removing A β T cell antigen epitope, keeping its β cell antigen epitope becomes first-selection.

Recently the second filial generation AD vaccine of bibliographical information still has many unsatisfactory places: 1) antigen for preparing of researcheres mostly is chemosynthesis greatly, and the chemical modification difficulty of synthetic peptide is big, the cost height, and also purity is not high.2) researcheres are when preparation contains the polyvalent vaccine of A β N-terminal B cell antigen epi-position, be that B cell antigen epi-position fragment directly is connected with a new t cell epitope mostly, perhaps the B cell antigen epi-position is directly connected, the antigenic space structure of influence is unfavorable for the exposure of the B cell antigen epi-position of A β easily.

Summary of the invention

Purpose of the present invention is exactly in order to overcome the above-mentioned shortcoming of preparation alzheimer disease vaccine, provides that a kind of toxicity is little, immunogenicity good, connects a kind of alzheimer disease reorganization multivalence A β of A β B cell antigen epi-position with flexible peptide _1-15Protein vaccine, one embodiment of the present of invention provide reorganization tetravalence A β _1-15Protein vaccine (4 * A β ₁₅).Another object of the present invention is for the method for this vaccine of production that cost is low, chemical purity is high is provided.

For achieving the above object, the present invention takes following design: synthetic many oligonucleotide primers, the two or more bivalence A β that contain the flexible peptide linker gene that obtain by gene amplification _1-15Gene segment is cloned in the pQE-30 prokaryotic expression plasmid (available from the commercial plasmid of German Qiagene company), through bacteria-induction express, purification, prepare and can express A β _1-15Be connected to form the multivalence A β of flexible foldable between aminoacid sequence by flexible peptide linker _1-15Recombinant protein vaccine.Wherein, described A β _1-15Aminoacid sequence is:

Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln

Flexible peptide linker is general to adopt one or the less essential amino acid of several (mostly being below four) molecular weight to connect, as glycine, serine etc., its sequence can for:

Gly-Gly or Gly-Ser-Ser-Gly

Wherein, flexible peptide linker has been avoided the rigid structure in the space of multicopy A β B cell antigen epi-position, also makes A β ₁₅The easier exposure of epi-position has strengthened immunogenicity.Simultaneously also increase immunogenic molecular weight, reduced the probability of degraded.

The preferred A β of the present invention ₁₅Aminoacid sequence is a tetravalence, i.e. 4 * A β ₁₅In this case, protein vaccine has stronger immunogenicity, and its production method is comparatively simple simultaneously.

Alzheimer disease reorganization multivalence A β of the present invention _1-15The production method of protein vaccine may further comprise the steps:

(1) synthetic many oligonucleotide primers, two or more that obtain by gene amplification contain the bivalence A β of flexible peptide linker gene _1-15Gene segment; Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Gly-Gly-Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Gly-Ser-Ser-Gly (2 * A β _15-1) and

Gly-Ser-Ser-Gly-Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Gly-Gly-Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln(2×Aβ _15-2)；

(2) with the two or more bivalence A β that contain the flexible peptide linker gene _1-15Gene segment is cloned in the pQE-30 prokaryotic expression plasmid (available from the commercial plasmid of German Qiagene company) successively, preparation recombiant plasmid pQE-4 * A β ₁₅

(3) with recombiant plasmid pQE-4 * A β ₁₅Be transformed into the expression bacterium M15[pREP4 that contains the pREP4 plasmid] in, IPTG (isopropyl-β-D-thiogalactopyranoside, isopropylthiogalactoside) abduction delivering 4 * A β ₁₅Recombiant protein;

4 * A β that (4) will express ₁₅Recombiant protein is through his-tag Ni ²⁺Behind affinity purification resin (histidine-tagged nickel ion affinity purification resin is available from the German Qiagene company) purification, dialysis obtains highly purified 4 * A β ₁₅Recombiant protein;

(5) with highly purified 4 * A β ₁₅Recombiant protein is prepared into 4 * A β after mixing with the adjuvant equal-volume is fully emulsified ₁₅Recombinant protein vaccine.

The present invention selects the folding A β of multivalence _1-15Be immunogen, avoided the rigid structure in space of multicopy A β B cell antigen epi-position, also make A β ₁₅The easier exposure of epi-position has strengthened immunogenicity.Simultaneously also increase immunogenic molecular weight, reduced the probability of degraded.Select prokaryotic expression system to prepare recombiant protein, avoided the highly difficult and expensive shortcoming of chemosynthesis.

The adjuvant that the present invention can select has MF59 and aluminium adjuvant etc., preferably is adjuvant with MF59, can promote immunoreation to the Th2 direction polarization.

The specific embodiment

The invention will be further described below in conjunction with embodiment, and embodiments of the invention are to be used for further specifying of the present invention, but can not be interpreted as that embodiments of the present invention only limit to embodiments of the invention.

Embodiment one is with the folding A β of tetravalence _1-15Preparation for immunogenic recombinant protein vaccine may further comprise the steps:

1 recombiant plasmid pQE-4 * A β ₁₅Preparation

1.1 tetravalence B cell antigen epi-position segment 4 * A β of pQE-30 is inserted in design ₁₅Sequence is: A β _1-15+ GG+A β _1-15+ GSSG+A β _1-15+ GG+A β _1-15

1.2 recombiant plasmid pQE-4 * A β ₁₅Make up

1.2.1A β _1-15+ GG+A β _1-15+ GSSG (Sac I) (2 * A β ₁₅-1, i.e. first bivalence A β _1-15Gene) segmental design of primers

P1 primer: 5 '-CG

GAT GCA GAA TTC CGA CAT GAT TCAGGA TAT GAA GTT CAT CAT CAA

GAT GCA GAA TTC CGACAT GAT TCA GGA TAT GAA GTT CAT CAT CAA GG

G-3 '.The italic overstriking is the glycine connection peptides, is respectively A β before and after the glycine connection peptides ₁₅Base sequence, overstriking are respectively BamHI and Sac I restriction enzyme site, and underscore is the paired base of primer.

The P2 primer: 5 '- C

CC TTG ATG ATG AAC-3 '; Overstriking is a Sac I restriction enzyme site, and underscore is the paired base of primer;

(1.2.2GSSG Sac I)+A β _1-15+ GG+A β _1-15(2 * A β _15-2, i.e. second bivalence A β _1-15Gene) segmental design of primers

P3 primer: 5 '-G

G GGT GAT GCA GAA TTC CGA CAT GATTCA GGA TAT GAA GTT CAT CAT CAA

GAT GCA GAA TTCCGA CAT GAT TCA GGA TAT GAA GTT CAT CAT CAA TGA

GGG-3 '; The italic overstriking is the glycine connection peptides, is respectively A β before and after the glycine connection peptides ₁₅Base sequence, overstriking are respectively Sac I and Hind III restriction enzyme site, and underscore is the paired base of primer;

The P4 primer: 5 '- CCC

TCA TTG ATG ATG AAC-3 '; Overstriking is the HindIII restriction enzyme site, and underscore is the paired base of primer;

1.2.32 * A β _15-1Segmental amplification

P1, P2 are primer, are template with synthetic P1 primer, Ex Taq enzyme, 94 ℃ of pre-degeneration 5min, 94 ℃ of degeneration 45s then; 52 ℃ of annealing 30s; 72 ℃ are extended 45s, 30 circulations.Last 72 ℃ are extended 7min, amplification P2 * A β _15-1Fragment.1.5% sepharose electrophoresis observation amplification, PCR product purification test kit purification.

1.2.42 * A β _15-2Segmental amplification

P3, P4 are primer and template, Ex Taq enzyme, 94 ℃ of pre-degeneration 5min, 94 ℃ of degeneration 45s then; 52 ℃ of annealing 30s; 72 ℃ are extended 45s, 30 circulations.Last 72 ℃ are extended 7min, amplification 2 * A β _15-2Fragment.

1.2.5pQE-4 * A β ₁₅Structure

With BamH I and Sac I double digestion 2 * A β _15-1Fragment and pQE-30.Reclaim wire pQE-30 carrier and 2 * A β _15-1Fragment, the T4DNA ligase, 16 ℃ of connections of spending the night, transformed competence colibacillus E.coliDH5a, select transformant, contain the LB culture medium incubated overnight of ampicillin, the Omega plasmid prepares test kit in a small amount and extracts plasmid, identify positive recombinant called after pQE-2 * A β in 37 ℃ of double digestions with BamH I/Sac I _15-1Equally, with Sac I and Hind III double digestion 2 * A β _15-2Fragment and pQE-2 * A β _15-1, reclaim wire pQE-2 * A β _15-1Carrier and 2 * A β _15-2Endonuclease bamhi, the T4 dna ligase, 16 ℃ of connections of spending the night, transformed competence colibacillus E.coli DH5a obtains positive recombinant PQE-4 * A β ₁₅

2 recombiant plasmid pQE-4 * A β ₁₅Expression and evaluation

PQE-4 * A β ₁₅Transform M15[pREP4] bacterium, 1mM IPTG induced 6 hours for 30 ℃, got the contrast thalline and expressed 4 * A β ₁₅Thalline, after the sample loading buffer cracking, boil 10min after, 12000rpm, centrifugal 10min gets sample on the 20 μ l supernatants.5% concentrates glue, the PAGE glue of the preparation of 20% separation gel (Polyacrylamide Gel Electrophoresis, polyacrylamide gel electrophoresis), Tricine{ three (methylol) methylglycine) electrophoretic buffer carries out SDS-PAGE (Sodium Dodecyl SulfatePolyacrylamide Gel Electrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis) electrophoresis, deposition condition: the about 40min of first 40v constant voltage, when treating that sample enters separation gel, voltage rises to constant voltage 60v, about 3h.The 100v electricity changes 1.5h to polyvinylidene fluoride (PolyvinylideneFluioride again, PVDF) on the film, with 5% defatted milk powder sealing 2h, added anti-A β monoclonal antibody (1: 2000, Sigma) hatch 1h, after TBST (Tris Buffer Saline Tween, tween Tris alkali buffer) buffer washs 5 times, add HRP-sheep anti-mouse igg (1: 4000), hatch 1h.After the TBST buffer washing 5 times, develop, the while is with the GST-A β of the applicant's prokaryotic expression and purification ₄₂Peptide is the positive control of immunoblotting (WesternBlotting) experiment.

3 reorganization, 4 * A β ₁₅Protein expression and purification

Cultivate the 2000ml bacterial cultures, 600nm optical density (OD) value (OD600) is 0.6 o'clock adding 1mol IPTG 2ml, 30 ℃ of 200rpm jolting 11h.Culture after results are induced, the centrifugal 5min precipitation of 12000g bacterium liquid is abandoned supernatant.1 * the PBS that adds 4 ℃ of pre-coolings of 100ml in the precipitation is resuspended.Ice-bath ultrasonic, power 30%, ultrasonic 10s, 30s continues 40min at interval, avoids bubbling.After the liquid change was limpid, 4 ℃, the centrifugal 30min of 13000g got supernatant.His-tag Ni in the supernatant after the adding balance ²⁺Affinity purification resin (histidine-tagged nickel ion affinity purification resin, available from German Qiagene company) 2ml, room temperature rotation mixing 30min, the centrifugal 5min of 500g abandons supernatant, and adding 10ml lavation buffer solution (Washing buffer) is resuspended in the precipitation, put upside down mixing 5min repeatedly, the centrifugal 5min of 500g abandons supernatant, repeats 2 times.Adding 1ml dissolving buffer (Elution Buffer) in the precipitation, room temperature rotation mixing 10min, the centrifugal 5min of 500g collects supernatant, repeats 2 times, merges the supernatant of 3 collections, after the dialysis, gets sample SDS-PAGE electrophoresis and WesternBlotting evaluation on the 5 μ l.With 4 * A β ₁₅Albumen concentrates and measures to be delivered to test center's row Electrospray Mass Spectrometry under the cryopreservation behind the protein concentration and tests its purity.

4 reorganization, 4 * A β ₁₅The preparation of protein vaccine

Reorganization 4 * A β ₁₅The adjuvant MF59 of albumen and equivalent (span850.5ml, PBS 94ml is made into 100 mixed liquors, mixes back emulsifying 15min for zamene 5ml, Tween80 0.5ml) mixes and is prepared into reorganization 4 * A β after fully emulsified ₁₅Protein vaccine.

In the present embodiment, A β ₁₅Be A β _1-15

Example example two reorganization 4 * A β ₁₅Immunology, pathology and behavioristics's viewing test behind the protein vaccine inoculation Tg2576 transgenic mice.

1 materials and methods

1.1 12 12 monthly age Tg2576 of laboratory animal transgenic mice (the Tg2576 transgenic mice is a U.S. Taconic company product, and breeds successfully in this chamber).Be divided into 2 groups at random after raising for 12 monthly ages: 4 * A β ₁₅Group and PBS matched group, every group each 6.

1.2 immunity inoculation reorganization 4 * A β ₁₅The adjuvant MF59 of albumen and equivalent (span85 0.5ml, PBS 94ml is made into 100 mixed liquors, mixes back emulsifying 15min for zamene 5ml, Tween80 0.5ml) mixes and is prepared into reorganization 4 * A β after fully emulsified ₁₅Protein vaccine, with the 100 μ g/time back Tg2576 Mus at subcutaneous multi-point injection 6 12 monthly ages of inoculation, per injection 100 μ L,, after the 1st inoculation, two week back reinforcements 1 time, later on once every the inoculation of 4 weeks.The 6th time the inoculation back is not inoculated for the 7th time, carries out antibody titer and measures.

1.3 (enzyme-linked immunosorbent assay, ELISA) method detects anti-A β in the serum to indirect ELISA ₄₂Titre

The blood sampling of Mus tail, after solidifying, centrifugalize serum, indirect elisa method detect A β antibody.GST-A β in order to this seminar prokaryotic expression and purification ₄₂Peptide (glutathione sulfydryl transferase, glutathioneS-transferase GST) are antigen coated elisa plate, every hole 1 μ g (0.05M carbonate buffer solution, pH9.0 preparation), and 4 ℃ of bags are spent the night.After PBST (phosphate buffer saline tween, tween phosphate buffer) washed plate, in 37 ℃, 3%BSA (Bovine Serum Albumin, bovine serum albumin) sealed 2h.Blood serum sample is since 1: 20 doubling dilution, parallel two holes, 100 μ l/ holes, 37 ℃, 2h; With the negative contrast of mice serum of PBS matched group immunity inoculation, the positive contrast of A β monoclonal antibody.PBST washes plate four times, after patting dry, adds the sheep anti-mouse igg (1: 5000) of horseradish peroxidase-labeled, and 37 ℃, 1h; PBST washes plate four times, after patting dry, adding TMB (3,3 ', 5,5-Tetramethylbenzidine, 3,3,5,5-tetramethyl benzidine) substrate, color development at room temperature 10min, 2mol/L H ₂SO ₄Stop, microplate reader is measured the OD value (optical density, optical density (OD)) of 450nm.(the blank OD of measured value OD-)/(the blank OD of negative control OD-) is more than or equal to 2.1, and experimental group OD value is judged as the positive greater than 0.4.

1.4Morris water maze behavioristics test

The Morris water maze mainly is made up of three parts, promptly includes round pool, self-recording unit and the computer for analysis system of platform.The pond is made by corrosion resistant plate, diameter 100cm, the dark 40cm in pond, and platform is made by transparent organic glass, and the high 29cm of platform adds water to 30cm.Add milk powder in the water and become milky, make the water surface not see platform, water temperature keeps about 20 ℃.By the quadrant coordinate of marking in the computer for analysis system, labelling east (E, X-axis positive pole), south (S, Y-axis negative pole), west (W, X-axis negative pole), north (N, Y-axis positive pole) 4 place of entry.Self-recording unit comprises photographic head, video camera and computer composition, and video camera links to each other with computer.The automatic analysis software of computer Morris water maze, animal swimming track is analyzed automatically, analysis result comprises mice swimming trajectory diagram, all quadrants swimming time and distance, 20% marginal zone, 40% marginal zone and swimming path, central area account for whole paths ratio, find the time (escape latency) of platform etc. for the first time.

Before the orientation navigation test test, allow few Mus free swimming one day, morning and afternoon each once, each 2min.Platform is placed on first quartile during test, mice respectively from east, south, west, north (E, S, W, N) four quadrants puts into the pond in the face of pool wall, mice is found behind the platform after platform keeps 30s, the next place of entry of being expert at is tested, surpass calculating that 60s do not find, get the escape latency time to take statistics by 60s.Respectively test a unit (block) morning and afternoon every day, continuous 4 days, totally 8 block.

Space exploration is tested the 8th orientation navigation experiment and is finished recession except that platform, make mice under no platform situation, seek the memory in platform, swimming 60s, getting the number of times that passes platform and platform quadrant swimming time accounts for total time percentage ratio and takes statistics, it is more that the mouse of memoryless obstacle passes the platform number of times, the swimming time percentage ratio height of platform quadrant.In the whole test process, the object of reference of peripheral pool (comprising experimenter institute station location) is constant, and experiment is finished in quiet environment.

1.5 sandwich method ELISA detects the synthetic of antigenic specificity (Enzyme-Linked ImmunosorbentAssay, indirect ELISA) IFN-(IFN-γ) and white thin plain plain-4 (IL-4) that are situated between

The mouse spleen lymphocyte suspension is added 96 hole polystyrene Tissue Culture Plates, and every hole 100 μ L contain 2 * 10 ⁵Individual cell.Add 4 * A β ₁₅With A β ₄₂(earlier with the distilled water dissolving, again with RPMI1640 culture medium mixing), 4 * A β ₁₅With A β ₄₂Final concentration all is 10 μ g/ml.37 ℃, 5%CO ₂, cultivate 72h.Take out Tissue Culture Plate, draw supernatant ,-20 ℃ frozen.1: 250 coated antibody is added 96 hole polystyrene enzyme reaction plates, every hole 100 μ L, 4 ℃ are spent the night.Remove liquid, PBST (phosphatebuffer saline tween, tween phosphate buffer) washing 3 times, each 5min.1% BSA-PBS (0.01M PBS preparation contains 0.3%Triton X-100, contains 1% bovine serum albumin BSA) sealing, every hole 200 μ L, incubated at room 1h.Remove liquid, PBST washing 3 times, each 5min.The standard substance and the sample that add the multiple proportions dilution, every hole 100 μ L, incubated at room 5h.Remove liquid, PBST washing 5 times, each 5min.Add 1: 250 biotin labeled detection antibody, every hole 100 μ L, incubated at room 1h.Remove liquid, PBST washing 5 times, each 5min.Add 1: 250 HRP-anti-biotin antibodies (anti-biotin antibodies of horseradish peroxidase-labeled), every hole 100 μ L, incubated at room 30min.Remove liquid, PBST washing 7 times, each 5min.Add substrate solution 3,3,5, the 5-tetramethyl benzidine (3,3 ', 5,5-Tetramethylbenzidine, TMB), every hole 100 μ L, incubated at room 15min.Add stop buffer, every hole 50 μ L.Measure every hole A value down in wavelength 450nm, positive with P/N=2.1, determination experiment result in 20min.

Each is organized sample and adds 4 * A β respectively ₁₅With A β ₄₀Each sample is done 3 multiple holes.Positive control adds coenzyme A (ConA), and every hole 50 μ L contain ConA 5 μ g/ml.Negative control only adds culture fluid.Experimental procedure is carried out in strict accordance with the explanation of test kit.Be the IFN-γ that avoids containing among the BSA and IL-4 influence to testing result, during cell culture with the RPMI1640 culture fluid that does not contain BSA.According to the measurement result of standard substance, the reference standard curve is tried to achieve IFN-γ in the sample and the content of IL-4.

1.6 the detection of senile plaque and quantitative analysis

Cerebral tissue is drawn materials, and the fixed full brain of 4% paraformaldehyde is used for the detection and the quantitative analysis of senile plaque.Cerebral tissue dehydration, embedding, the thick 8 μ m of brain tissue slice show on the microscope slide of handling through binder.Adopt Cell immunohistochemical staining method, methanol (contains 3%H ₂O ₂) reaction 20min, 0.01M phosphate buffer PBS (pH 7.4) washing 5min * 3 time, 70% formic acid instils and leave standstill 5min after section, 0.01M PBS washing 5min * 3 time, 1%BSA, 37 ℃ of sealing 30min add anti-A β ₄₂Monoclonal antibody (1: 2000), 37 ℃ of 2h go to 4 ℃ again and spend the night, and 0.01M PBS washing 5min * 3 time add the goat anti-mouse IgG antibody (1: 200) of peroxidase labelling, hatch 2h for 37 ℃; 0.01M PBS washing 5min * 3 time, 0.05%DAB (3,3 '-diaminobenzidine, diaminobenzidine) (contains 0.03%H ₂O ₂) colour developing 5-10min, after microscopically sees that senile plaque is painted, 0.01MPBS washing stop buffer cessation reaction.Dehydration, transparent, neutral gum mounting, microscopically is observed.Select dorsal part Hippocampus position, every interval 40 μ m get a brain sheet, and every mouse brain is got 6 brain sheets and is used for quantitative analysis.The position of analyzing is the senile plaque of whole Hippocampus and top parietal association cortex thereof.Use Leica microscope and supporting software system and the JVC ky-F30B 3-CCD coloured image recording system of picking up that the senile plaque area is carried out quantitative analysis, calculate the percentage ratio that parietal association cortex and Hippocampus position amyloid plaques area account for cortex and Hippocampus area.Calculate as the amyloid plaques area percentage at a mice parietal association cortex and Hippocampus position the average back of the result of 6 sections of every mouse brain.

2 results

2.1 ordinary circumstance

Blood sampling for the first time (the 2nd inoculation 2 weeks of back) experimental group has anti-A β ₄₂Production of antibodies, but each group produces the amount difference of antibody.Along with increasing of inoculation times, the titre of each experimental group antibody is all increasing.Each is organized the average titer demonstration experimental group of Mus serum antibody and compares P＜0.01 with matched group.Experimental session, it is normal that each organizes Tg2576 mice outward appearance; Diet does not have significant change; Hair does not have and comes off; The mental status is good; Consciousness; Quadruped locomotion is normal; Obvious inflammatory reaction is not seen at the immunity position.

Brain, liver and kidney HE dyeing show that the brain cortex cell is clear, and well arranged cytoarchitectonic is no abnormal; The hepatocyte form is clear, and the lobules of liver structure is normal; Glomerule and renal tubules morphosis are normal; The Perls dyeing reaction that is negative shows that vaccination does not cause that the Tg2576 mouse brain is hemorrhage.

2.2 the typing of immunne response after the vaccination (antigenic specificity IFN-γ and IL-4's is synthetic)

ConA is as positive control, and PBS is as negative control, 4 * A β ₁₅Stimulate as specific antigen, use IFN-γ and IL-4 in the eBioscience Mouse Th1/Th2 ELISA Read-SET-GO test kit detection supernatant.With 4 * A β ₁₅Stimulate splenocyte to collect after 3 days in the supernatant that produces, the content of IL-4 is higher than IFN-γ; Compare with the PBS group, significant difference (P＜0.01) is arranged, the results are shown in Table 1.Show reorganization 4 * A β ₁₅Protein vaccine immune transgenic mice has been induced the immunoreation based on the Th2 type.

Table 1 after different antigenic stimulus the content of cytokine in the Tg2576 mouse boosting cell culture supernatant (x ± s, pg/ml)

Compare with the PBS group, ^*P＜0.01.

2.3Morris water maze test result

Get the escape latency average of three groups of mices of each block, as seen along with the increase of mice study number of times, the escape latency of each group all shortens gradually.The escape latency of each block is compared 4 * A β with the PBS group ₁₅Group difference all has significance (P＜0.01).

The ring of wearing after platform is withdrawn is tested, and recently judges learning and memory in rats and mice apart from percentage ratio and the swimming of 20% marginal zone apart from percentage with spanning platform number of times, the swimming of platform quadrant.PBS group, 4 * A β ₁₅The group mice passes the platform number of times and is respectively 1.17 ± 0.89 times and 5.33 ± 1.50 times; 4 * A β ₁₅Group is organized increased frequency than PBS, and difference has significance (P＜0.01); And the swimming of platform quadrant is respectively 22.48 ± 3.56% and 51.61 ± 5.75%, 4 * A β apart from percentage ratio ₁₅Group is organized to have obviously than PBS and is increased, and difference has significance (P＜0.01); The swimming of 20% marginal zone is respectively 44.8 ± 5.25% and 13.8 ± 5.02% apart from percentage ratio, 4 * A β ₁₅Group obviously descends than the PBS group, and difference has significance (P＜0.01).The results are shown in Table 2.

Table 2 is respectively organized the space exploration experimental result of mice

Compare with the PBS group, ^*P＜0.01.

2.4 the detection of senile plaque and quantitative analysis

After the vaccination 6 months, 4 * A β at 18 monthly ages ₁₅Group and all visible amyloid plaques of PBS group Mus senile plaque dyeing, macula densa, disc of confusion all exist, the macula densa compact structure, sharpness of border, how rounded, there is a comparatively fine and close nuclear at the center of speckle.The center at speckle that has but presents an irregular olistherozone.Mainly be distributed in the cortex and the Hippocampus of cortex, top and the frontal lobe of splenium of corpus callosum rear and occipital lobe, white matter and other no plaque deposition in zone take place.The graphical analysis quantitative result shows that PBS organizes the Tg2576 Mus amyloid plaques area at 18 monthly ages and accounts for brain sheet area average out to 4.28 ± 2.41%.And 4 * A β ₁₅Group amyloid deposition speckle obviously reduces, and area is less, and mean patch area accounts for 2.27 ± 0.66% of respective area, and comparing difference with the PBS group has significance (P＜0.001).

The result shows: show 4 * A β of prokaryotic expression preparation by immune Tg2576 mice ₁₅Protein vaccine can the inducing specific production of antibodies, causes the immunne response based on the Th2 type.Reorganization 4 * A β ₁₅Protein vaccine can stop the decline of cognitive function of Tg2576 Mus, improves its learning and memory function.The vaccination group is compared with matched group, and the quantity of its senile plaque obviously reduces.Therefore, the reorganization tetravalence A β of the present invention's preparation _1-15Protein vaccine will will have broad prospects in the treatment of AD.

Claims (5)

1, a kind of senile dementia recombinant protein vaccine is reorganization multivalence A β _1-15Protein vaccine, described A β _1-15Aminoacid sequence is:

Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln

A β _1-15Adopt flexible peptide linker to be connected to form multivalence A β between aminoacid sequence _1-15

2, a kind of senile dementia recombinant protein vaccine according to claim 1, the sequence that it is characterized in that said flexible peptide linker is Gly-Gly or Gly-Ser-Ser-Gly.

3, a kind of senile dementia recombinant protein vaccine according to claim 1 and 2 is characterized in that said A β _1-15Aminoacid sequence is a tetravalence, i.e. 4 * A β _1-15

4, a kind of senile dementia recombinant protein vaccine according to claim 1 and 2 is characterized in that in the protein vaccine with MF59 being adjuvant.

5, the preparation method of a kind of senile dementia recombinant protein vaccine as claimed in claim 1 comprises the steps: may further comprise the steps:

(1) synthetic many oligonucleotide primers, two or more that obtain by gene amplification contain the bivalence A β of flexible peptide linker gene _1-15Gene segment; Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Gly-Gly-Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Gly-Ser-Ser-Gly (2 * A β _15-1) and

Gly-Ser-Ser-Gly-Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln-Gly-Gly-Asp-Ala-Glu-Phe-Arg-His-Asp-Ser-Gly-Tyr-Glu-Val-His-His-Gln(2×Aβ _15-2)；

(2) with the two or more bivalence A β that contain the flexible peptide linker gene _1-15Gene segment is cloned in the pQE-30 prokaryotic expression plasmid successively, preparation recombiant plasmid pQE-4 * A β ₁₅

(3) with recombiant plasmid pQE-4 * A β ₁₅Be transformed into respectively and express bacterium M15[pREP4], IPTG abduction delivering 4 * A β ₁₅Recombiant protein;

4 * A β that (4) will express ₁₅Recombiant protein is through his-tag Ni ²⁺Behind the affinity purification resin purification, dialysis obtains highly purified 4 * A β ₁₅Recombiant protein;

(5) with highly purified 4 * A β ₁₅Recombiant protein is prepared into 4 * A β after mixing with the adjuvant equal-volume is fully emulsified ₁₅Recombinant protein vaccine.