GENESIS: Co-location of Geodetic Techniques in Space

Improving and homogenizing time and space reference systems on Earth and, more directly, realizing the Terrestrial Reference Frame (TRF) with an accuracy of 1mm and a long-term stability of 0.1mm/year are relevant for many scientific and societal endeavors. The knowledge of the TRF is fundamental for Earth and navigation sciences. For instance, quantifying sea level change strongly depends on an accurate determination of the geocenter motion but also of the positions of continental and island reference stations, as well as the ground stations of tracking networks. Also, numerous applications in geophysics require absolute millimeter precision from the reference frame, as for example monitoring tectonic motion or crustal deformation for predicting natural hazards. The TRF accuracy to be achieved represents the consensus of various authorities which has enunciated geodesy requirements for Earth sciences. Today we are still far from these ambitious accuracy and stability goals for the realization of the TRF. However, a combination and co-location of all four space geodetic techniques on one satellite platform can significantly contribute to achieving these goals. This is the purpose of the GENESIS mission, proposed as a component of the FutureNAV program of the European Space Agency. The GENESIS platform will be a dynamic space geodetic observatory carrying all the geodetic instruments referenced to one another through carefully calibrated space ties. The co-location of the techniques in space will solve the inconsistencies and biases between the different geodetic techniques in order to reach the TRF accuracy and stability goals endorsed by the various international authorities and the scientific community. The purpose of this white paper is to review the state-of-the-art and explain the benefits of the GENESIS mission in Earth sciences, navigation sciences and metrology.Comment: 31 pages, 9 figures, submitted to Earth, Planets and Space (EPS

Immunization against Leishmania major Infection Using LACK- and IL-12-Expressing Lactococcus lactis Induces Delay in Footpad Swelling

BACKGROUND: Leishmania is a mammalian parasite affecting over 12 million individuals worldwide. Current treatments are expensive, cause severe side effects, and emerging drug resistance has been reported. Vaccination is the most cost-effective means to control infectious disease but currently there is no vaccine available against Leishmaniasis. Lactococcus lactis is a non-pathogenic, non-colonizing Gram-positive lactic acid bacterium commonly used in the dairy industry. Recently, L. lactis was used to express biologically active molecules including vaccine antigens and cytokines. METHODOLOGY/PRINCIPAL FINDINGS: We report the generation of L. lactis strains expressing the protective Leishmania antigen, LACK, in the cytoplasm, secreted or anchored to the bacterial cell wall. L. lactis was also engineered to secrete biologically active single chain mouse IL-12. Subcutaneous immunization with live L. lactis expressing LACK anchored to the cell wall and L. lactis secreting IL-12 significantly delayed footpad swelling in Leishmania major infected BALB/c mice. The delay in footpad swelling correlated with a significant reduction of parasite burden in immunized animals compared to control groups. Immunization with these two L. lactis strains induced antigen-specific multifunctional T(H)1 CD4(+) and CD8(+) T cells and a systemic LACK-specific T(H)1 immune response. Further, protection in immunized animals correlated with a Leishmania-specific T(H)1 immune response post-challenge. L. lactis secreting mouse IL-12 was essential for directing immune responses to LACK towards a protective T(H)1 response. CONCLUSIONS/SIGNIFICANCE: This report demonstrates the use of L. lactis as a live vaccine against L. major infection in BALB/c mice. The strains generated in this study provide the basis for the development of an inexpensive and safe vaccine against the human parasite Leishmania

Engineered «Lactoccus lactis» live vaccines against «Leishmania major»

The neglected tropical disease leishmaniasis affects over 12 million individuals worldwide and causes high morbidity and significant mortality. Treatments against the parasitic disease are limited by cost, severe side-effects and emerging resistance against treatment. While vaccination provides the most cost-effective means to combat infectious diseases, there is currently no human vaccine available against Leishmania infections. Lactococcus lactis is a non-pathogenic, non-colonizing Gram-positive lactic acid bacteria commonly used in the dairy industry. Recently, L. lactis was used for the expression and delivery of biologically active molecules and was shown to be safe and well tolerated in humans after oral administration. We report the successful engineering of L. lactis strains expressing the protective Leishmania antigen, LACK, at three different subcellular locations: cytoplasmically, secreted, and cell-wall-anchored, and a strain of L. lactis secreting biologically active mouse IL-12. We further generated strains of L. lactis co-expressing LACK and IL-12. These live vaccine strains were then tested for their efficacy in the mouse model of cutaneous leishmaniasis. We found that subcutaneous immunization with L. lactis expressing LACK anchored to the cell wall and L. lactis secreting IL-12 protected BALB/c mice against Leishmania major infection. Further, oral immunization with L. lactis, secreting both LACK and IL-12 protected to a similar level as the subcutaneous immunization against parasite challenge. Both subcutaneous and oral immunization induced LACK-specific humoral responses, systemically or at the mucosa, respectively. Further, a systemic antigen-specific Th1 immune response was detectable in oral and subcutaneous immunized animals pre-challenge. Protection in these animals correlated in both cases with a local and systemic anti-Leishmania Th1 immune response post-challenge. Taken together, these findings demonstrate the use of L. lactis as a live vaccine against L. major infection in BALB/c mice. The L. lactis strains generated provide the basis for the development of a safe live vaccine against the human parasite Leishmania.La leishmaniose est une maladie tropicale orpheline qui affecte plus de 12 millions de personnes dans le monde et est associée à une forte morbidité ainsi qu'une importante mortalité. Les traitements disponibles contre cette maladie d'origine parasitaire sont limités part leurs coûts, leurs effets secondaires sévères et l'émergence de résistance envers ceux-ci. De plus, bien que la vaccination soit de nos jours la méthode la moins dispendieuse afin de combattre les maladies infectieuses, aucun vaccin contre les infections causées par Leishmania n'est présentement disponible. Lactococcus lactis est une bactérie lactique Gram positive non pathogène et non colonisante couramment utilisée par l'industrie laitière. L. lactis a récemment été utilisée pour transporter et exprimer des molécules biologiquement actives et il a été démontré que son utilisation par voie orale était sécuritaire et bien tolérée par les humains. Nous sommes parvenus à développer une souche de L. lactis exprimant l'antigène protecteur contre Leishmania LACK dans deux compartiments différents, soit dans le cytoplasme ou ancrée dans la paroi cellulaire et sécrétée, ainsi qu'une souche de L. lactis secrétant une forme active d'IL-12 murin. De plus, nous avons généré des souches de L. lactis co-exprimant LACK et IL-12. Nous avons ensuite testé l'efficacité de ces souches comme vaccins vivants en utilisant le model murin de leishmaniose cutanée. Nous avons trouvé que les souris BALB/c pouvaient être protégées contre les infections à Leishmania major suite à une immunisation sous-cutanée avec les souches de L. lactis exprimant LACK sur la paroi cellulaire ou sécrétant l'IL-12. Par ailleurs, nous avons démontré qu'une immunisation orale avec une souche de L. lactis sécrétant LACK et IL-12 protégeait contre le parasite avec une efficacité similaire à celle observée lors de l'immunisation sous-cutanée. Tant les immunisations sous-cutanées qu'orales ont permis d'induire une réponse humorale spécifique à LACK, respectivement systémique et mucosale. De plus, une réponse Th1 systémique et antigène-spécifique est détectée, pour les deux types d'immunisation, chez les animaux immunisés avant une exposition au parasite. Dans les deux cas, cette protection corrèle à une réponse Th1 anti-Leishmania locale et systémique suite à une nouvelle exposition. Ces nouvelles observations démontrent l'efficacité de l'emploi de L. lactis comme vaccin vivant contre les infections à Leishmania major dans des souris BALB/c. Ainsi, ces nouvelles souches générées pourraient fournir la base au développement d'un vaccin sécuritaire contre Leishmania chez l'humain

Galileo Orbit and Clock Quality of the IGS Multi-GNSS Experiment

The Multi-GNSS Experiment (MGEX) of the International GNSS Service (IGS) aims at the data collection and analysis of all available satellite navigation systems. In particular the new global and regional satellite navigation systems are of interest, i.e., the European Galileo, the Chinese BeiDou, the Japanese QZSS as well as satellite based augmentation systems. This article analyzes the orbit and clock quality of the Galileo products of four MGEX analysis centers for a common time period of 20 weeks. Orbit comparisons of the individual analysis centers have a consistency at the 5–30 cm level. Day boundary discontinuities range from 4 to 28 cm whereas 2-day orbit fit RMS values vary between 1 and 7 cm. The accuracy evaluated by satellite laser ranging residuals is on the one decimeter level with a systematic bias of about −5 cm for all analysis centers. In addition, systematic errors on the decimeter level related to solar radiation pressure mismodeling are present in all orbit products. Due to the correlation of radial orbit errors with the clock parameters, these errors are also visible as a bump in the Allan deviation of the Galileo satellite clocks at the orbital frequency

5

When the IGS was renamed from “International GPS Service” to “International GNSS Service ” the IGS Governing Board and the IGS community expressed their expectation to extend activities from the well–established GPS to othe

Antigen-specific humoral immune response following immunization with LACK-expressing <i>L. lactis</i>.

<p>Mice were immunized three times subcutaneously with PBS or different strains of <i>L. lactis</i> and blood was collected one week after the last immunization (A), four weeks after challenge (B) or ten weeks after challenge (C). LACK-specific IgG₁ and IgG_2a antibody titers in sera were determined by ELISA. Mean and SEM of four to five mice per group are shown. * <i>P</i><0.05 by unpaired T-test to PBS and <i>L. lactis</i>/vector. Data shown are representative of two independent experiments with similar results.</p

Protection against <i>L. major</i> infection correlates with <i>Leishmania</i>-specific T_H1 response in immunized animals.

<p>Mice were immunized three times subcutaneously with PBS or different strains of <i>L. lactis</i> and challenged with <i>L. major</i>. Mice were sacrificed eight days (A, B), or ten weeks (C–G) after challenge (pm: <i>post mortem</i>). Lymph node cells (A–E), or splenocytes (F, G) were restimulated with SLA <i>ex vivo</i>. IFN-γ, IL-10, and IL-2 secretion by restimulated draining lymph node cells and splenocytes were determined by ELISA. Mean and SEM of four to five mice per group are shown. * <i>P</i><0.05; ** <i>P</i><0.01 by unpaired T-test to PBS and <i>L. lactis</i>/vector. ^▴<i>P</i><0.05 by unpaired T-test to PBS. Data shown are representative of two independent experiments with similar results.</p

Expression and localization of the <i>Leishmania</i> LACK antigen and single-chain mouse IL-12 in <i>L. lactis</i>.

<p>(A) Western blot of total protein extracts of LACK-expressing strains of <i>L. lactis</i>. T, total cell extract; S, culture supernatant. (B) Localization of expressed LACK was confirmed by whole cell ELISA using anti-LACK antibody. C, intact cells; S, culture supernatant. * <i>P</i><0.05 by unpaired T-test to <i>L. lactis</i>/vector. Data shown are representative of three independent experiments with similar results. (C) Total protein extracts of <i>L. lactis</i> were analyzed for IL-12 expression by Western blot using anti-IL-12p70 antibody. (D) Secretion of IL-12 by <i>L. lactis</i> was quantified using mouse IL-12p70 ELISA. * <i>P</i><0.05 by unpaired T-test to <i>L. lactis</i>/secIL-12 wt. Data shown are representative of at least three independent experiments with similar results. (E) IFN-γ secretion by BALB/c splenocytes stimulated with αCD3/αCD28 in combination with rIL-12 or concentrated supernatant from <i>L. lactis</i> secreting IL-12 was determined by ELISA. * <i>P</i><0.05 by unpaired T-test to αCD3/αCD28. Data shown are representative of three independent experiments with similar results.</p

Immunization with <i>L. lactis</i>/cwaLACK and <i>L. lactis</i>/secIL-12 induces systemic T_H1 immune responses and multifunctional T_H1 cells pre-challenge.

<p>Mice were immunized three times subcutaneously with PBS or different strains of <i>L. lactis</i>. Mice were sacrificed two weeks after the last immunization and splenocytes were restimulated with purified LACK antigen <i>ex vivo</i>. (A, B) IFN-γ, IL-10, and (C) IL-2 secretion after three days of restimulation was determined by ELISA. (D) Splenocytes were restimulated for 16 hours and cytokine expression was analyzed by flow cytometry. Frequencies of CD4⁺ and CD8⁺ T cells positive for IFN-γ, IL-2, or TNF-α or the combination of the different cytokines are shown. (E) Fraction of the total CD4⁺ or CD8⁺ response comprising cells expressing any two cytokines (2+), or any one cytokine (1+). Mean and SEM of four to five mice per group are shown. * <i>P</i><0.05; ** <i>P</i><0.01 by unpaired T-test to PBS and <i>L. lactis</i>/vector. ^▴<i>P</i><0.05 by unpaired T-test to PBS. Data shown are representative of two independent experiments with similar results.</p