Generation and characterization of the humoral immune response to DNA immunization with a chimeric beta-amyloid-interleukin-4 minigene

Active immunization with fibrillar beta-amyloid peptide (AB42) as well as passive transfer of anti-AB antibodies significantly reduces AB plaque deposition, neuritic dystrophy, and astrogliosis in the brain of mutant amyloid precursor protein (APP)-transgenic mice. Although the mechanism(s) of clearance of AB from the brain following active or passive immunization remains to be determined, it is clear that anti-AB antibodies are critical for clearance. DNA immunization provides an attractive alternative to direct peptide and adjuvant approaches for inducing a humoral response to AB. We constructed a DNA minigene with AB fused to mouse interleukin-4 (pAB42-IL-4) as a molecular adjuvant to generate anti-AB antibodies and enhance the Th2-type of immune responses. Gene gun immunizations induced primarily IgG1 and IgG2b anti-AB antibodies. Fine epitope analysis with overlapping peptides of the AB42 sequence identified the 1- 15 region as a dominant B cell epitope. The DNA minigeneinduced anti-AB antibodies bound to AB plaques in brain tissue from an Alzheimer's disease patient demonstrating functional activity of the antibodies and the potential for therapeutic efficacy. Originally published European Journal of Immunology, Vol. 33, No. 12, Dec 200

Reducing AD-Like Pathology in 3xTg-AD Mouse Model by DNA Epitope Vaccine — A Novel Immunotherapeutic Strategy

BACKGROUND: The development of a safe and effective AD vaccine requires a delicate balance between providing an adequate anti-Abeta antibody response sufficient to provide therapeutic benefit, while eliminating an adverse T cell-mediated proinflammatory autoimmune response. To achieve this goal we have designed a prototype chemokine-based DNA epitope vaccine expressing a fusion protein that consists of 3 copies of the self-B cell epitope of Abeta(42) (Abeta(1-11)) , a non-self T helper cell epitope (PADRE), and macrophage-derived chemokine (MDC/CCL22) as a molecular adjuvant to promote a strong anti-inflammatory Th2 phenotype. METHODS AND FINDINGS: We generated pMDC-3Abeta(1-11)-PADRE construct and immunized 3xTg-AD mouse model starting at age of 3-4 months old. We demonstrated that prophylactic immunizations with the DNA epitope vaccine generated a robust Th2 immune response that induced high titers of anti-Abeta antibody, which in turn inhibited accumulation of Abeta pathology in the brains of older mice. Importantly, vaccination reduced glial activation and prevented the development of behavioral deficits in aged animals without increasing the incidence of microhemorrhages. CONCLUSIONS: Data from this transitional pre-clinical study suggest that our DNA epitope vaccine could be used as a safe and effective strategy for AD therapy. Future safety and immunology studies in large animals with the goal to achieve effective humoral immunity without adverse effects should help to translate this study to human clinical trials

Mimotopes selected with a neutralizing antibody against urease B from Helicobacter pylori induce enzyme inhibitory antibodies in mice upon vaccination

<p>Abstract</p> <p>Background</p> <p>Urease B is an important virulence factor that is required for <it>Helicobacter pylori </it>to colonise the gastric mucosa. Mouse monoclonal antibodies (mAbs) that inhibit urease B enzymatic activity will be useful as vaccines for the prevention and treatment of <it>H. pylori </it>infection. Here, we produced murine mAbs against urease B that neutralize the enzyme's activity. We mapped their epitopes by phage display libraries and investigated the immunogenicity of the selected mimotopes <it>in vivo</it>.</p> <p>Results</p> <p>The urease B gene was obtained (GenBank accession No. <ext-link ext-link-id="DQ141576" ext-link-type="gen">DQ141576</ext-link>) and the recombinant pGEX-4T-1/UreaseB protein was expressed in <it>Escherichia coli </it>as a 92-kDa recombinant fusion protein with glutathione-S-transferase (GST). Five mAbs U001-U005 were produced by a hybridoma-based technique with urease B-GST as an immunogen. Only U001 could inhibit urease B enzymatic activity. Immunoscreening via phage display libraries revealed two different mimotopes of urease B protein; EXXXHDM from ph.D.12-library and EXXXHSM from ph.D.C7C that matched the urease B proteins at 347-353 aa. The antiserum induced by selected phage clones clearly recognised the urease B protein and inhibited its enzymatic activity, which indicated that the phagotope-induced immune responses were antigen specific.</p> <p>Conclusions</p> <p>The present work demonstrated that phage-displayed mimotopes were accessible to the mouse immune system and triggered a humoral response. The urease B mimotope could provide a novel and promising approach for the development of a vaccine for the diagnosis and treatment of <it>H. pylori </it>infection.</p

Electrosynthesis of gold nanocomposites based on a copolymer of 1-vinyl-1,2,4-triazol with crotonic acid

In this work, we have synthesized and discussed the results of electrosynthesis of metal-polymer nanocomposites of gold. Nanocoatings were made on pure iron and steel electrodes by combining the process of electropolymerization of 1-vinyl-1.2.4-triazole with crotonic acid and cathodic deposition of gold. Using UV, IR and atomic absorption spectro­scopies, X-ray phase analysis, as well as thermogravimetric and elemental analyses, the structure and composition of the synthesized nanocomposites and nano­composite coatings were studied