Deletion of parasite immune modulatory sequences combined with immune activating signals enhances vaccine mediated protection against filarial nematodes

<p>Background: Filarial nematodes are tissue-dwelling parasites that can be killed by Th2-driven immune effectors, but that have evolved to withstand immune attack and establish chronic infections by suppressing host immunity. As a consequence, the efficacy of a vaccine against filariasis may depend on its capacity to counter parasite-driven immunomodulation.</p> <p>Methodology and Principal Findings: We immunised mice with DNA plasmids expressing functionally-inactivated forms of two immunomodulatory molecules expressed by the filarial parasite Litomosoides sigmodontis: the abundant larval transcript-1 (LsALT) and cysteine protease inhibitor-2 (LsCPI). The mutant proteins enhanced antibody and cytokine responses to live parasite challenge, and led to more leukocyte recruitment to the site of infection than their native forms. The immune response was further enhanced when the antigens were targeted to dendritic cells using a single chain Fv-αDEC205 antibody and co-administered with plasmids that enhance T helper 2 immunity (IL-4) and antigen-presenting cell recruitment (Flt3L, MIP-1α). Mice immunised simultaneously against the mutated forms of LsALT and LsCPI eliminated adult parasites faster and consistently reduced peripheral microfilaraemia. A multifactorial analysis of the immune response revealed that protection was strongly correlated with the production of parasite-specific IgG1 and with the numbers of leukocytes present at the site of infection.</p> <p>Conclusions: We have developed a successful strategy for DNA vaccination against a nematode infection that specifically targets parasite-driven immunosuppression while simultaneously enhancing Th2 immune responses and parasite antigen presentation by dendritic cells.</p&gt

Spatially resolved simulation of a radio frequency driven micro atmospheric pressure plasma jet and its effluent

Radio frequency driven plasma jets are frequently employed as efficient plasma sources for surface modification and other processes at atmospheric pressure. The radio-frequency driven micro atmospheric pressure plasma jet ($\mu$APPJ) is a particular variant of that concept whose geometry allows direct optical access. In this work, the characteristics of the $\mu$APPJ operated with a helium-oxygen mixture and its interaction with a helium environment are studied by numerical simulation. The density and temperature of the electrons, as well as the concentration of all reactive species are studied both in the jet itself and in its effluent. It is found that the effluent is essentially free of charge carriers but contains a substantial amount of activated oxygen (O, O$_3$ and O$_2(^1\Delta)$). The simulation results are verified by comparison with experimental data

The secreted triose phosphate isomerase of Brugia malayi is required to sustain microfilaria production in vivo

Human lymphatic filariasis is a major tropical disease transmitted through mosquito vectors which take up microfilarial larvae from the blood of infected subjects. Microfilariae are produced by long-lived adult parasites, which also release a suite of excretory-secretory products that have recently been subject to in-depth proteomic analysis. Surprisingly, the most abundant secreted protein of adult Brugia malayi is triose phosphate isomerase (TPI), a glycolytic enzyme usually associated with the cytosol. We now show that while TPI is a prominent target of the antibody response to infection, there is little antibody-mediated inhibition of catalytic activity by polyclonal sera. We generated a panel of twenty-three anti-TPI monoclonal antibodies and found only two were able to block TPI enzymatic activity. Immunisation of jirds with B. malayi TPI, or mice with the homologous protein from the rodent filaria Litomosoides sigmodontis, failed to induce neutralising antibodies or protective immunity. In contrast, passive transfer of neutralising monoclonal antibody to mice prior to implantation with adult B. malayi resulted in 60–70% reductions in microfilarial levels in vivo and both oocyte and microfilarial production by individual adult females. The loss of fecundity was accompanied by reduced IFNγ expression by CD4+ T cells and a higher proportion of macrophages at the site of infection. Thus, enzymatically active TPI plays an important role in the transmission cycle of B. malayi filarial parasites and is identified as a potential target for immunological and pharmacological intervention against filarial infections

Eosinophils Are Important for Protection, Immunoregulation and Pathology during Infection with Nematode Microfilariae

Eosinophil responses typify both allergic and parasitic helminth disease. In helminthic disease, the role of eosinophils can be both protective in immune responses and destructive in pathological responses. To investigate whether eosinophils are involved in both protection and pathology during filarial nematode infection, we explored the role of eosinophils and their granule proteins, eosinophil peroxidase (EPO) and major basic protein-1 (MBP-1), during infection with Brugia malayi microfilariae. Using eosinophil-deficient mice (PHIL), we further clarify the role of eosinophils in clearance of microfilariae during primary, but not challenge infection in vivo. Deletion of EPO or MBP-1 alone was insufficient to abrogate parasite clearance suggesting that either these molecules are redundant or eosinophils act indirectly in parasite clearance via augmentation of other protective responses. Absence of eosinophils increased mast cell recruitment, but not other cell types, into the broncho-alveolar lavage fluid during challenge infection. In addition absence of eosinophils or EPO alone, augmented parasite-induced IgE responses, as measured by ELISA, demonstrating that eosinophils are involved in regulation of IgE. Whole body plethysmography indicated that nematode-induced changes in airway physiology were reduced in challenge infection in the absence of eosinophils and also during primary infection in the absence of EPO alone. However lack of eosinophils or MBP-1 actually increased goblet cell mucus production. We did not find any major differences in cytokine responses in the absence of eosinophils, EPO or MBP-1. These results reveal that eosinophils actively participate in regulation of IgE and goblet cell mucus production via granule secretion during nematode-induced pathology and highlight their importance both as effector cells, as damage-inducing cells and as supervisory cells that shape both innate and adaptive immunity

Современные тенденции в разработке эффективных комбикормов для рыб

The successful development of the fish industry in the Republic of Belarus requires the provision of aquaculture facilities with low-cost, high-quality, safe and effective feed. Institute of Fish Industry of the National Academy of Sciences of Belarus is developing new types of domestic raw materials of waste industry, in particular fish processing waste. This high-protein raw material is the best for freshwater fish, especially for valuable species. Currently, laboratory samples of fish hydrolyzate have been obtained, which can replace imported fish meal by 10–15 % in composition of compound feed for fish, which will make it possible to reduce the price of domestic feed by 7–10 %. Development of hydrolyzate from fish processing waste will create a closed cycle of fish processing with production of high-quality compound feed raw materials. A new treatment-and-prophylactic compound feed “Mix-Feed” and its specifications have been developed. Compound feed is intended for prevention and treatment of bacterial infections of carp fish, natural phytobiotic Mix-Oil is used in its composition in the amount of 600 g/t. Moisture-and-heat treatment modes of “Mix-Feed” compound feed was selected to preserve its activity. Conducted production tests at the republic's fish farms showed that compound feed “Mix-Feed” increases survival rate of carp by 80 % when fighting against bacterial infections. Compound feed “Mix-Feed” allows to eliminate the use of antibiotics for prevention and treatment of bacterial infections of carp, which allows to obtain environmentally friendly products being in demand in the world market. The new feed has already been used at large fish farms of the Republic of Belarus (fish farm “Volma” and OFH “Selets”). In cooperation with SPS “Armbiotechnology” of the National Academy of Sciences of Armenia and the National Polytechnic University of Armenia, natural preservative from wine production wastes is being developed. Tartaric acid benzylimide, isolated from wine production waste, showed high activity against conditionally pathogenic strains of salmonella and staphylococcus, causing high mortality of fish when using contaminated compound feed. In the future, this development will allow domestic feeds to become competitive in terms of storage period. Для успешного развития рыбной отрасли в Республике Беларусь требуется обеспечение объектов аквакультуры недорогими, качественными, безопасными и эффективными комбикормами. Институт рыбного хозяйства Национальной академии наук Беларуси разрабатывает новые виды отечественного сырья из отходов перерабатывающих производств, в частности отходов переработки рыбы. Данное высокобелковое сырье является наилучшим для пресноводной рыбы, особенно для ценных видов. В настоящее время получены лабораторные образцы рыбного гидролизата, который способен заменить импортную рыбную муку на 10–15 % в составе комбикормов для рыбы, что позволит удешевить отечественный комбикорм на 7–10 %. Разработка гидролизата из отходов переработки рыбы позволит создать замкнутый цикл переработки рыбы с получением высококачественного комбикормового сырья. Разработан новый лечебно-профилактический комбикорм «Микс-Корм» и технические условия на него. Комбикорм предназначен для профилактики и лечения бактериальных инфекций карповых рыб, в его составе используется натуральный фитобиотик «Микс-Оил» в количестве 600 г/т. Подобраны режимы влаготепловой обработки комбикорма «Микс-Корм» для сохранения его активности. Производственные испытания, проведенные в рыбхозах республики, показали, что комбикорм «Микс-Корм» повышает выживаемость карпа на 80 % при борьбе с бактериальными инфекциями. Комбикорм «Микс-Корм» позволяет исключить использование антибиотиков при профилактике и лечении бактериальных инфекций карпа, что дает возможность получать экологически чистую продукцию, востребованную на мировом рынке. Новый комбикорм уже используется крупными рыбхозами Республики Беларусь (рыбхоз «Волма» и ОРХ «Селец»). Совместно с НПЦ «Армбиотехнология» Национальной академии наук Республики Армения и Национальным политехничнским университетом Армении разрабатывается натуральный консервант из отходов винного производства. Бензилимид винной кислоты, выделенный из отходов винного производства, показал высокую активность в отношении условно-патогенных штаммов сальмонеллы и стафиллокока, вызывающих высокую смертность рыбы при использовании зараженных ими комбикормов. Данная разработка в перспективе позволит сделать отечественные комбикорма конкурентосособными по срокам хранения.

On inconsistency of experimental data on primary nuclei spectra with sea level muon intensity measurements

For the first time a complete set of the most recent direct data on primary cosmic ray spectra is used as input into calculations of muon flux at sea level in wide energy range $E_\mu=1-3\cdot10^5$ GeV. Computations have been performed with the CORSIKA/QGSJET and CORSIKA/VENUS codes. The comparison of the obtained muon intensity with the data of muon experiments shows, that measurements of primary nuclei spectra conform to sea level muon data only up to several tens of GeV and result in essential deficit of muons at higher energies. As it follows from our examination, uncertainties in muon flux measurements and in the description of nuclear cascades development are not suitable to explain this contradiction, and the only remaining factor, leading to this situation, is underestimation of primary light nuclei fluxes. We have considered systematic effects, that may distort the results of the primary cosmic ray measurements with the application of the emulsion chambers. We suggest, that re-examination of these measurements is required with the employment of different hadronic interaction models. Also, in our point of view, it is necessary to perform estimates of possible influence of the fact, that sizable fraction of events, identified as protons, actually are antiprotons. Study of these cosmic ray component begins to attract much attention, but today nothing definite is known for the energies $>40$ GeV. In any case, to realize whether the mentioned, or some other reasons are the sources of disagreement of the data on primaries with the data on muons, the indicated effects should be thoroughly analyzed