Browsing by Subject "Adjuvans"

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Entwicklung und Testung neuer DNA- und Protein-basierter Multikomponentenvakzinen sowie regulatorischer Adjuvanzien gegen eine Infektion mit B. anthracis in Auszucht-Mäusen und Ziegen
(2015) Köhler, Susanne Melanie; Beyer, Wolfgang
The discovery of the Sterne spore live vaccine (SSLV) and subsequently its application in a veterinary context contributed to the global reduction of Anthrax related outbreaks since 1930. Nonetheless the causative agent Bacillus anthracis is still prevalent in some mediterranean countries, South and Central America, Africa and Central Asia, as well as the USA and Canada. Reasons for this are the persistence of the pathogen in the soil, as well as still undefined factors for an ongoing cycle of outbreak and spread of the disease and the limited applicability of the SSLV. This includes the necessity to revaccinate annually, the residual virulence in certain sensitive species (e. g. goats and llamas) and the incompatibility to treat and vaccinate simultaneously. To participate in the ongoing search for alternative vaccines this work was dedicated to evaluate protein- and DNA-based components as potential ingredients for a multi-component non-living vaccine formulation (NLV). For the protein-based NLV these included rPA83 as part of the Anthrax toxin, rBclA and Formalin inactivated spores (FIS) as spore specific antigens, a Capsule-Lipopeptide conjugate as part of the vegetative form of the pathogen and a Lipopeptide-adjuvant. The DNA-vaccines consisted of vector-backbones comprising signal sequences able to direct the integrated antigens (rPA83, PAD4LFD1 and BclAD1D3) to the MHCI, MHCII and the secretory pathway. A sperate vector encoding for a positive MHCII-regulator (CIITA) and a vector internal sequence for the Interferon-ß promotor stimulator (mIPS1) served as adjuvants for the DNA-vaccines. The majority of the groups showed detectable antibody titres against their respective antigens, with protein vaccines generally eliciting higher titres against rPA83 than the DNA-vaccines. Regarding rBclA equivalent high titres were measured for protein- and DNA-vaccines alike, which also corresponded to the anti-FIS titres for groups immunized with rBclA, FIS or both. The Capsule-Lipopeptide conjugate did not elicit high titres against the capsule, possibly due to an immune suppressing epitope. Survival rates ranged between 10 and 100 %, with full protection only achieved in a combination of all antigens including FIS. All DNA-vectors induced 30 – 50 % protectiveness when given alone. Notably DNA-vectors including BclAD1D3 elicited 50 % survival and sterile immunity. A combination of the most promising vectors encoding for toxin and spore specific antigens achieved 90 % protectiveness in mice. According to the results from the mice trials, the auspicious protein- and DNA-vaccine combinations were tested in goats in comparison to the SSLV in cooperation with our project partners in South Africa and Turkey. The efficacy of the SSLV was assessed in 3 groups which were challenged shortly after the first immunisation, one year after the first immunisation or after the revaccination. Apart from the comparison of immunogenicity and protectiveness between SSLV and NLV in goats, assessment of data concerning the titre development of SSLV-immunized goats during the course of a year as well as detailed diagnostic data during the infection (behavior, temperature, bacterial loads, correlations and minimal infective dose) were integral part of this study. Compared to one another the SSLV-immunized animals showed equal or higher antibody titres against the measured antigens, with FIS and rPA83 being the most immunogen antigens. Utilizing a higher dose (75 µg) the protein-based NLV protected equivalently to the SSLV (60 – 100 %) yielding 50 % protectiveness without FIS and 80 % if FIS was included. The DNA-vaccines showed little to no immunogenicity in goats, thus no challenge was performed on these animals. The humoral reaction against BclA was generally poor in goats, which has not been noted before and could be a basis for further improvements concerning the SSLV and NLV alike. The different immunizations with the SSLV revealed a broad range for the efficacy of the first vaccination as well as a notable difference in the antibody spectrum between first vaccination and revaccination. Together with the recorded data of the antibody titre development throughout a year a more optimal protocol for immunisation with the SSLV, possibly in combination with an NLV was postulated.
Studies on the efficacy, composition and mode of action of an ethoxylated soybean oil adjuvant for herbicides
(2012) Heini, Julia; Gerhards, Roland
The potential of an ethoxylated soybean oil adjuvant ? Agnique® SBO 10 ? to increase the efficacy of different herbicides was investigated in the present thesis. Furthermore, Agnique® SBO 10 was fractioned by preparative High-Performance Liquid Chromatography (prep. HPLC) to elucidate the composition of the ethoxylated soybean oil (ESBO). In addition, experiments with fluorescein-labelled Agnique® SBO 10 were conducted to evaluate the fate of modified seed oil adjuvants on the leaf surface. The efficacy of many herbicides can be increased by adding adjuvants to the spray solution. Adjuvants, in particular surfactants, are able to increase the foliar uptake of active ingredients for example, by enhancing the retention of spray droplets on cuticles, penetration and absorption into leaf tissue. Agnique® SBO 10 belongs to a group of environmental friendly surfactant containing ten ethylene oxide units. Modified seed or vegetable oils are biodegradable and are proposed to be as effective as petroleum oils. These facts make them very interesting for the usage as adjuvants for agrochemicals. To evaluate the potency of Agnique® SBO 10 dose-response studies were accomplished. Results showed that sulfosulfuron, topramezone, and foramsulfuron & iodosulfuron did not control velvetleaf (Abutilon theophrasti Medik.) sufficiently when they were applied without adjuvant. Agnique® SBO 10 acted 2-fold better compared to the recommended adjuvants. Thus, Agnique® SBO 10 could present an alternative adjuvant for a widespread use. These results show, that a certain adjuvant has the potential to increase the efficacy of a herbicide to its maximum. However, for the user it is not easy to choose a proper adjuvant of the broad range of available products. Thus, integrating additives into pesticide formulations is desirable. Due to the fact, that Agnique® SBO 10 is a huge and complex product it cannot be included into a formulation. For this reason, an experiment was accomplished dividing Agnique® SBO 10 into four fractions by using preparative HPLC. These four fractions were isolated of Agnique® SBO 10 and tested in combination with commercially formulated herbicides (foramsulfuron & iodosulfuron and bromoxynil octanoate) and a technical grade bromoxynil product. The aim was to find a fraction with a higher potential compared to Agnique® SBO 10 to be used as low-molecular adjuvant. The herbicide-fraction mixtures were applied as droplets with a pipette on velvetleaf leaves. Dry weight and leaf area measurements of test plants demonstrated that the efficacy of foramsulfuron & iodosulfuron and the technical bromoxynil was increased with decreasing polarity of isolated fractions of Agnique® SBO 10, whereas the efficiency of bromoxynil octanoate was tendentially enhanced adding more polar fractions to the herbicide solution. Again, it was demonstrated that the herbicide?s efficacy is strongly dependent of the adjuvant/fractions. Though a lot of research was conducted to confirm the positive effect of adjuvants on herbicides, their mode of action is still not completely clear. Because modified vegetable oils are complex compounds, a radioactive labelling is not easy. Therefore, in this study Agnique® SBO 10 was labelled with fluorescein to investigate, whether Agnique® SBO 10 remains on the leaf surface, accumulates in the cuticle or even penetrates into the underlying plant tissue. Fluorescein-labelled Agnique® SBO 10 (AF) was applied to one leaf of the test species velvetleaf, wild mustard and sugar beet. At different time intervals, treated leaves were harvested and rinsed with different washing solutions (deionised water, methanol/water and chloroform). The washed leaves and the respective washing solutions were processed separately and analyzed with HPLC coupled with an UV detector. Results lead to the assumption that AF might have been passed through the cuticle. However, AF is not expected to be very mobile because it is lipophilic and electrically neutral. If there was a penetration through the cuticle, an enzymatic metabolisation of Agnique® SBO 10 into fatty acids and ethoxylated glycerol is likely to occur. With this thesis the herbicide-enhancing effect of Agnique® SBO 10 was confirmed. Furthermore, a new approach for the design of optimized adjuvants for precise herbicide-adjuvant mixtures was presented. Though a lot of research has to be conducted to elucidate the mode of action of adjuvants, this study gives an approach to investigate the behaviour of foliar applied adjuvants.