ABSTRACT
Alzheimer's disease (AD) is a neurodegenerative disorder that impairs memory and cognition. The neuropathological features of the disease include neurofibrillary tangles, deposition of β-amyloid (Aβ) in senile plaques and neuronal loss in affected brain regions. The amyloid cascade hypothesis suggests that production and accumulation of excessive β- amyloid may be the main cause of the onset and progression of Alzheimer's disease. Active and passive immunotherapy targeting β- amyloid may be the most promising strategy to prevent or treat AD. This review seeks to put perspective to the mixed results obtained so far in pre-clinical and clinical trials of AD vaccines and antibodies targeting β-amyloid and discusses the perspective and novel direction of successful AD immunotherapy. Novel strategies for the design of more effective therapeutic vaccines are suggested.
ABSTRACT
A completely synthetic gene encoding the He domain of Clostridium botulinum neurotoxin serotype A (AHc, 1287 bp, 429 aa, -50 kD) was constructed with oligonucleotides. After expressed in Escherichia coli, soluble product AHc was gained and verified by SDS-PAGE and Western blot analysis. The expressive level of recombinant AHc in E. coli was very high (36%-53% of soluble total proteins) and the purified yield was more than 30 mg/L by one-step purification. Then, the purified AHc was used to vaccinate Balb/c mice, which developed a strong and specific immune response as expected following administration of AHe protein via the subcutaneous route. Results from BoNT/A neutralization assay showed that the serum from mice vaccinated with AHc contained high titer protective antibody. These results showed that the soluble, stable and high-levelly expressive AHc not only could be produced by the prokaryotic expression system built in our lab, but also owned strong immunogenicity to prepare antitoxin for treatment and as sub-unit candidate vaccine for prophylaxis against botulinum toxin serotype A.
Subject(s)
Animals , Female , Mice , Antibodies, Bacterial , Blood , Bacterial Vaccines , Genetics , Allergy and Immunology , Botulinum Toxins, Type A , Genetics , Allergy and Immunology , Botulism , Allergy and Immunology , Clostridium botulinum type A , Genetics , Allergy and Immunology , Escherichia coli , Genetics , Metabolism , Lymphocyte Activation , Mice, Inbred BALB C , Recombinant Proteins , Genetics , Allergy and Immunology , T-Lymphocytes , Allergy and Immunology , Vaccines, DNA , Genetics , Allergy and ImmunologyABSTRACT
Objective:To determine if suitable electric pulses-mediated DNA and DNA and bupivacaine complexes delivery technologies could enhance effects of botulinum neurotoxin serotype A (BoNT/A) DNA vaccines in mouse model. Methods:Vaccination of mice i.m. with plasmid DNA replicon vaccine pSCARSHc and conventional plasmid DNA vaccine pcDNASHc following electric pulses and with DNA and bupivacaine complexes. AHc-specific group antibody ELISA titers and lymphocyte proliferative responses of mice were detected and IgG1 and IgG2a isotype profiles were assayed. Results:Immune effects of DNA vaccines were enhanced following electric pulses and bupivacaine delivery. Effects of DNA vaccines following electric pulses were better than that of DNA vaccines formulated with bupivacaine,and the combined delivery technology of electric pulses and bupivacaine induced the highest level of specific antibodies and lymphocyte proliferative responses. Plasmid DNA replicon vaccine pSCARSHc induced relatively higher AHc-specific antibodies and lymphocyte proliferative responses in immunized Balb/c mice than conventional plasmid DNA vaccine pcDNASHc in these DNA delivery technologies. And vaccine pSCARSHc induced Th2/Th1-type immune responses with a general bias to Th2-type,and vaccine pcDNASHc induced Th2-type immune responses. Conclusion:Suitable electric pulses-mediated DNA and DNA and bupivacaine complexes delivery technologies could enhance effects of BoNT/A DNA vaccines in mouse model. Therefore,the methods described here potentially provide suitable strategies in developing an efficacious vaccine against botulinum neurotoxin serotype A.
ABSTRACT
DNA-based replicon expression vector pSMCTA and helper vector pSHCTA were constructed by replacing the SP6 promoter used in the original system pSFV1 and pSFV-helper2 derived from Semliki Forest virus (SFV) with the RNA polymerase II -dependent cytomegalovirus immediate early (CMV IE) enhancer/promoter and T7 promoter, and inserting BGH transcription termination and polyadenylation signal downstream 3'-untranslated region (UTR). The RNA polymerase II -dependent cytomegalovirus immediate early (CMV IE) enhancer/promoter and T7 promoter in pSMCTA and pSHCTA could drive transcription to produce replicon RNA in vivo and ex vivo. High level expression of foreign genes (GFP and LacZ) could be demonstrated by transfecting BHK21 cells with the new replicon expression vectors based on both DNA and RNA, and recombinant virus particles (RVP) be prepared by cotranfecting the expression vectors with the helper vectors. Foreign genes were also highly expressed in cells (BHK21) which were infected with RVP activated by alpha-chymotrypsin. The bifunctional replicon vectors can be used in highly efficient expression of foreign genes and preparation of RVP ex vivo, also in development of replicon vaccines and gene therapy vectors in vivo.