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Research: POTENCY TESTING OF NOVEL DTP GROUP OF VACCINES
Monika Sharma,Hemant Brahmne,Pallavi Bafna*
Pharmacie Globale : International Journal of Comprehensive Pharmacy , 2011,
Abstract: Conventionally, the production of DTP group of vaccines involves the growth of toxicogenic strains of C. diphtheria, C. tetani and B. pertussis on media of animal origin e.g. casein digests or meat extracts. These media pose various risks such as Bovine Spongiform Encephalopathy (BSE), microbial contamination and allergic reactions. To avoid such risks, media containing nutrients of vegetative origin are substituted, which support the growth of the pathogenic bacteria. The present study involves the potency testing of DTP group of vaccines produced on such vegetative media. The lethal challenge method and antibody induction method were the two methods used to determine the potency of this group of vaccines. The potency of these DTP vaccines was found to be well within limits set by the Indian Pharmacopoeia, 2007.
A combination of intradermal jet-injection and electroporation overcomes in vivo dose restriction of DNA vaccines  [cached]
Halleng?rd David,Br?ve Andreas,Isaguliants Maria,Blomberg Pontus
Genetic Vaccines and Therapy , 2012, DOI: 10.1186/1479-0556-10-5
Abstract: Background The use of optimized delivery devices has been shown to enhance the potency of DNA vaccines. However, further optimization of DNA vaccine delivery is needed for this vaccine modality to ultimately be efficacious in humans. Methods Herein we evaluated antigen expression and immunogenicity after intradermal delivery of different doses of DNA vaccines by needle or by the Biojector jet-injection device, with or without the addition of electroporation (EP). Results Neither needle injection augmented by EP nor Biojector alone could induce higher magnitudes of immune responses after immunizations with a high dose of DNA. After division of a defined DNA dose into multiple skin sites, the humoral response was particularly enhanced by Biojector while cellular responses were particularly enhanced by EP. Furthermore, a close correlation between in vivo antigen expression and cell-mediated as well as humoral immune responses was observed. Conclusions These results show that two optimized DNA vaccine delivery devices can act together to overcome dose restrictions of plasmid DNA vaccines.
A Review on DNA Vaccines
Journal of Health Science , 2011, DOI: 10.5923/j.health.20110101.01
Abstract: A DNA vaccine uses foreign DNA to express an encoded protein and stimulate the body's immune system. It represents a new approach to immunization which is potentially less expensive than the old vaccines. The development of DNA vaccines against the pathogens that use veterinary species as host is completely feasible and going on and it is a promising technology in veterinary sciences. There is promising approach for generating desired immunity: cytolytic T lymphocytes(CTL). Certain methods like gene gun and electroporation are used to deliver DNA vaccines but phage mediated immunization is the recent technology to deliver the DNA vaccines that offers an extremely elegant and rapid method for identifying potential vaccine candidates for newly emerging diseases or for pathogens for which protective antigens have not yet been identified. Antigen presenting cells like dendritic cells (DCs) play an important role in increasing the potency of DNA vaccines. Anti-angiogenic DNA vaccine may prove promising strategy for the treatment of the cancer. DNA vaccines undergo through clinical trials to find the way to treat autoimmune diseases, hepatitis, mycobacterial diseases, allergy and malaria.
Efficacy of seasonal pandemic influenza hemagglutinin DNA vaccines delivered by electroporation against aseasonal H1N1 virus challenge in mice
Lei Tan,HuiJun Lu,Dan Zhang,KaiYan Wang,MingYao Tian,CunXia Liu,YanYu LiU,Bo Hu,NingYi Jin
Science China Life Sciences , 2011, DOI: 10.1007/s11427-011-4150-5
Abstract: Prophylactic DNA vaccines against the influenza virus are promising alternatives to conventional vaccines. In this study, we generated two candidate gene-based influenza vaccines encoding either the seasonal or pandemic hemagglutinin antigen (HA) from the strains A/New Caledonia/20/99 (H1N1) (pV1A5) and A/California/04/2009 (H1N1) (pVEH1), respectively. After verifying antigen expression, the immunogenicity of the vaccines delivered intramuscularly with electroporation was tested in a mouse model. Sera of immunized animals were tested in hemagglutination inhibition assays and by ELISA for the presence of HA-specific antibodies. HA-specific T-cells were also measured in IFN-γ ELISpot assays. The protective efficacy of the candidate influenza vaccines was evaluated by measuring mortality rates and body weight after a challenge with 100 LD50 of mouse-adapted A/New Caledonia/20/99 (H1N1). Mice immunized with either one of the two vaccines showed significantly higher T cell and humoral immune responses (P<0.05) than the pVAX1 control group. Additionally, the pV1A5 vaccine effectively protected the mice against a lethal homologous mouse-adapted virus challenge with a survival rate of 100% compared with a 40% survival rate in the pVEH1 vaccinated group (P<0.05). Our study indicates that the seasonal influenza DNA vaccine completely protects against the homologous A/New Caledonia/20/99 virus (H1N1), while the pandemic influenza DNA vaccine only partially protects against this virus.
Induction of Neutralizing Antibody Response against Four Dengue Viruses in Mice by Intramuscular Electroporation of Tetravalent DNA Vaccines  [PDF]
Eakachai Prompetchara, Chutitorn Ketloy, Poonsook Keelapang, Nopporn Sittisombut, Kiat Ruxrungtham
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0092643
Abstract: DNA vaccine against dengue is an interesting strategy for a prime/boost approach. This study evaluated neutralizing antibody (NAb) induction of a dengue tetravalent DNA (TDNA) vaccine candidate administered by intramuscular-electroporation (IM-EP) and the benefit of homologous TDNA boosting in mice. Consensus humanized pre-membrane (prM) and envelope (E) of each serotypes, based on isolates from year 1962–2003, were separately cloned into a pCMVkan expression vector. ICR mice, five-six per group were immunized for three times (2-week interval) with TDNA at 100 μg (group I; 25 μg/monovalent) or 10 μg (group II; 2.5 μg/monovalent). In group I, mice received an addtional TDNA boosting 13 weeks later. Plaque reduction neutralization tests (PRNT) were performed at 4 weeks post-last immunization. Both 100 μg and 10 μg doses of TDNA induced high NAb levels against all DENV serotypes. The median PRNT50 titers were comparable among four serotypes of DENV after TDNA immunization. Median PRNT50 titers ranged 240–320 in 100 μg and 160–240 in 10 μg groups (p = ns). A time course study of the 100 μg dose of TDNA showed detectable NAb at 2 weeks after the second injection. The NAb peaked at 4 weeks after the third injection then declined over time but remained detectable up to 13 weeks. An additional homologous TDNA boosting significantly enhanced the level of NAb from the nadir for at least ten-fold (p<0.05). Of interest, we have found that the use of more recent dengue viral strain for both vaccine immunogen design and neutralization assays is critical to avoid a mismatching outcome. In summary, this TDNA vaccine candidate induced good neutralizing antibody responses in mice; and the DNA/DNA prime/boost strategy is promising and warranted further evaluation in non-human primates.
Preparing clinical-grade myeloid dendritic cells by electroporation-mediated transfection of in vitro amplified tumor-derived mRNA and safety testing in stage IV malignant melanoma
Svetomir N Markovic, Allan B Dietz, Carl W Greiner, Mary L Maas, Greg W Butler, Douglas J Padley, Peggy A Bulur, Jacob B Allred, Edward T Creagan, James N Ingle, Dennis A Gastineau, Stanimir Vuk-Pavlovic
Journal of Translational Medicine , 2006, DOI: 10.1186/1479-5876-4-35
Abstract: We prepared immature DCs (IDCs) from CD14+ cells isolated from leukapheresis products and extracted total RNA from freshly resected melanoma tissue. We reversely transcribed the RNA while attaching a T7 promoter to the products that we subsequently amplified by PCR. We transcribed the amplified cDNA in vitro and introduced the expanded RNA into IDCs by electroporation followed by DC maturation and cryopreservation. Isolated and expanded mRNA was analyzed for the presence of melanoma-associated tumor antigens gp100, tyrosinase or MART1. To test product safety, we injected five million DCs subcutaneously at three-week intervals for up to four injections into six patients suffering from stage IV malignant melanoma.Three preparations contained all three transcripts, one isolate contained tyrosinase and gp100 and one contained none. Electrotransfection of DCs did not affect viability and phenotype of fresh mature DCs. However, post-thaw viability was lower (69 ± 12 percent) in comparison to non-electroporated cells (82 ± 12 percent; p = 0.001). No patient exhibited grade 3 or 4 toxicity upon DC injections.Standardized preparation of viable clinical-grade DCs transfected with tumor-derived and in vitro amplified mRNA is feasible and their administration is safe.Dendritic cells (DCs) have been used in numerous recent clinical trials as vaccines intended to break tolerance to tumors and induce tumor-specific therapeutic immunity [1]. To break tolerance to the tumor, DCs must effectively present tumor-associated antigen(s). Antigens have been delivered to DC as whole-tumor lysates, natural or synthetic peptides, recombinant viruses, tumor specific RNA, and recombinant DNA [2]. Most of these sources have been used for clinical trials, particularly tumor lysates; however, tumor lysates are a limited and inconsistent source of antigenic material. The optimal method for antigen delivery to DCs is still controversial [2].A current discussion of antigen delivery to DCs concluded t
Electroporation-Induced Electrosensitization  [PDF]
Olga N. Pakhomova,Betsy W. Gregory,Vera A. Khorokhorina,Angela M. Bowman,Shu Xiao,Andrei G. Pakhomov
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0017100
Abstract: Electroporation is a method of disrupting the integrity of cell membrane by electric pulses (EPs). Electrical modeling is widely employed to explain and study electroporation, but even most advanced models show limited predictive power. No studies have accounted for the biological consequences of electroporation as a factor that alters the cell's susceptibility to forthcoming EPs.
Casimir force on amplifying bodies  [PDF]
Agnes Sambale,Dirk-Gunnar Welsch,Stefan Yoshi Buhmann,Ho Trung Dung
Physics , 2009, DOI: 10.1134/S0030400X10030124
Abstract: Based on a unified approach to macroscopic QED that allows for the inclusion of amplification in a limited space and frequency range, we study the Casimir force as a Lorentz force on an arbitrary partially amplifying system of linearly locally responding (isotropic) magnetoelectric bodies. We demonstrate that the force on a weakly polarisable/magnetisable amplifying object in the presence of a purely absorbing environment can be expressed as a sum over the Casimir--Polder forces on the excited atoms inside the body. As an example, the resonant force between a plate consisting of a dilute gas of excited atoms and a perfect mirror is calculated.
Evaluation of dendritic cells loaded with apoptotic cancer cells or expressing tumour mRNA as potential cancer vaccines against leukemia
Silvija Jarnjak-Jankovic, Rolf D Pettersen, Stein S?b?e-Larssen, Finn Wesenberg, Gustav Gaudernack
BMC Cancer , 2005, DOI: 10.1186/1471-2407-5-20
Abstract: This study focuses on dendritic cell (DC) vaccination of childhood leukemia and evaluates the in vitro efficacy of different strategies for antigen loading of professional antigen-presenting cells. We have compared DCs either loaded with apoptotic leukemia cells or transfected with mRNA from the same leukemia cell line, Jurkat E6, for their capacity to induce specific CD4+ and CD8+ T-cell responses. Monocyte-derived DCs from healthy donors were loaded with tumor antigen, matured and co-cultured with autologous T cells. After one week, T-cell responses against antigen-loaded DCs were measured by enzyme-linked immunosorbent spot (ELISPOT) assay.DCs loaded with apoptotic Jurkat E6 cells or transfected with Jurkat E6-cell mRNA were both able to elicit specific T-cell responses in vitro. IFNγ-secreting T cells were observed in both the CD4+ and CD8+ subsets.The results indicate that loading of DCs with apoptotic leukemia cells or transfection with tumour mRNA represent promising strategies for development of cancer vaccines for treatment of childhood leukemia.Leukemia represents the most common form of cancer in children. There are two main types of childhood leukemia, acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). The success rate in treatment of childhood leukemia has improved continuously over the past decades [1], and today disease-free survival is 70%–80% for ALL and 40%–60% for AML [2-4]. In the Nordic countries the overall event-free survival in ALL has risen from 57% to75% [2]. However, in children with high-risk ALL, the progress has only been modest. The relapse rate has decreased in parallel with the improving results, but the prognosis after relapse has not improved. Only 25%–30% of children who relapse will reach and remain in a second remission. Children with AML have a worse prognosis than those with ALL. Event-free survival for AML is below 55%, whereas the cure rate for children with ALL is near 80%. The complete remission rate diff
Statistical Mechanics of Amplifying Apparatus  [PDF]
Joseph Johnson
Physics , 2005,
Abstract: We implement Feynman's suggestion that the only missing notion needed for the puzzle of Quantum Measurement is the statistical mechanics of amplifying apparatus. We define a thermodynamic limit of quantum amplifiers which is a classically describable system in the sense of Bohr, and define macroscopic pointer variables for the limit system. Then we derive the probabilities of Quantum Measurement from the deterministic Schroedinger equation by the usual techniques of Classical Statistical Mechanics.
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