Recombinant Modified Vaccinia Virus Ankara Expressing Glycoprotein E2 of Chikungunya Virus Protects AG129 Mice against Lethal Challenge

Chikungunya virus (CHIKV) infection is characterized by rash, acute high fever, chills, headache, nausea, photophobia, vomiting, and severe polyarthralgia. There is evidence that arthralgia can persist for years and result in long-term discomfort. Neurologic disease with fatal outcome has been documented, although at low incidences. The CHIKV RNA genome encodes five structural proteins (C, E1, E2, E3 and 6K). The E1 spike protein drives the fusion process within the cytoplasm, while the E2 protein is believed to interact with cellular receptors and therefore most probably constitutes the target of neutralizing antibodies. We have constructed recombinant Modified Vaccinia Ankara (MVA) expressing E3E2, 6KE1, or the entire CHIKV envelope polyprotein cassette E3E26KE1. MVA is an appropriate platform because of its demonstrated clinical safety and its suitability for expression of various heterologous proteins. After completing the immunization scheme, animals were challenged with CHIV-S27. Immunization of AG129 mice with MVAs expressing E2 or E3E26KE1 elicited neutralizing antibodies in all animals and provided 100% protection against lethal disease. In contrast, 75% of the animals immunized with 6KE1 were protected against lethal infection. In conclusion, MVA expressing the glycoprotein E2 of CHIKV represents as an immunogenic and effective candidate vaccine against CHIKV infections

Pygo2 expands mammary progenitor cells by facilitating histone H3 K4 methylation

Recent studies have unequivocally identified multipotent stem/progenitor cells in mammary glands, offering a tractable model system to unravel genetic and epigenetic regulation of epithelial stem/progenitor cell development and homeostasis. In this study, we show that Pygo2, a member of an evolutionarily conserved family of plant homeo domain–containing proteins, is expressed in embryonic and postnatal mammary progenitor cells. Pygo2 deficiency, which is achieved by complete or epithelia-specific gene ablation in mice, results in defective mammary morphogenesis and regeneration accompanied by severely compromised expansive self-renewal of epithelial progenitor cells. Pygo2 converges with Wnt/β-catenin signaling on progenitor cell regulation and cell cycle gene expression, and loss of epithelial Pygo2 completely rescues β-catenin–induced mammary outgrowth. We further describe a novel molecular function of Pygo2 that is required for mammary progenitor cell expansion, which is to facilitate K4 trimethylation of histone H3, both globally and at Wnt/β-catenin target loci, via direct binding to K4-methyl histone H3 and recruiting histone H3 K4 methyltransferase complexes

Recombinant Modified Vaccinia Virus Ankara Expressing Glycoprotein E2 of Chikungunya Virus Protects AG129 Mice against Lethal Challenge

Chikungunya virus (CHIKV) infection is characterized by rash, acute high fever, chills, headache, nausea, photophobia, vomiting, and severe polyarthralgia. There is evidence that arthralgia can persist for years and result in long-term discomfort. Neurologic disease with fatal outcome has been documented, although at low incidences. The CHIKV RNA genome encodes five structural proteins (C, E1, E2, E3 and 6K). The E1 spike protein drives the fusion process within the cytoplasm, while the E2 protein is believed to interact with cellular receptors and therefore most probably constitutes the target of neutralizing antibodies. We have constructed recombinant Modified Vaccinia Ankara (MVA) expressing E3E2, 6KE1, or the entire CHIKV envelope polyprotein cassette E3E26KE1. MVA is an appropriate platform because of its demonstrated clinical safety and its suitability for expression of various heterologous proteins. After completing the immunization scheme, animals were challenged with CHIV-S27. Immunization of AG129 mice with MVAs expressing E2 or E3E26KE1 elicited neutralizing antibodies in all animals and provided 100% protection against lethal disease. In contrast, 75% of the animals immunized with 6KE1 were protected against lethal infection. In conclusion, MVA expressing the glycoprotein E2 of CHIKV represents as an immunogenic and effective candidate vaccine against CHIKV infections

Laser-induced incandescence applied to dusty plasmas

This paper reports on the laser heating of nanoparticles (diameters ≤1 μm) confined in a reactive plasma by short (150 ps) and intense (~63 mJ) UV (355 nm) laser pulses (laser-induced incandescence, LII). Important parameters such as the particle temperature and radius follow from analysis of the emission spectrum of the heated nanoparticles. The nanoparticles are not ideal black bodies, which is taken into account by calculating their emissivity using a light-scattering theory relevant to our conditions (Mie theory). Three sets of refractive index data from the literature serve as model input.\u3cbr/\u3eThe obtained radii range between 100 and 165 nm, depending on the choice of refractive index data set. By fitting the temperature decay of the particles to a heat exchange model, the product of their mass density and specific heat is determined as (1.3±0.5) J K\u3csup\u3e−1\u3c/sup\u3e cm\u3csup\u3e−3\u3c/sup\u3e, which is considerably smaller than the value for bulk graphite at the temperature our particles attain (3000 K): 4.8 J K\u3csup\u3e−1\u3c/sup\u3e cm\u3csup\u3e−3\u3c/sup\u3e.\u3cbr/\u3eThe particle sizes obtained \u3ci\u3ein situ\u3c/i\u3e with LII are compared with \u3ci\u3eex situ\u3c/i\u3e scanning electron microscopy analysis of collected particles. Quantitative assessment of the LII measurements is hampered by transport of particles in the plasma volume and the fact that LII probes locally, whereas the samples with collected particles have a more global character

Neutralization titers against CHIKV-S27 and CHIKV-IND/NL10.

<p>Neutralization titers against CHIKV-S27 and CHIKV-IND/NL10.</p

Detection of antigen expression.

<p>BHK-21 cells were infected with the respective candidate MVA vaccines and 24 hours later cells were fixed in methanol/acetone (1∶1) and stained for specific expression of CHIKV E1 (upper panel), E2 (middle panel) or MVA antigens (lower panel). The respective antigens were detected using rabbit polyclonal serum specific against E1, E2, and MVA as indicated. The staining confirmed the specific expression of the respective antigens and their purity. *Images were contrast enhanced in Adobe Photoshop.</p

Survival of mice after vaccination and challenge infection with CHIKV.

<p>(<b>A</b>). Mice (n = 8) were immunized intra-muscularly with MVA-6KE1, MVA-E3E2, MVA-E3E26KE1 or MVA-wt. Subsequently, the mice were challenged intra-peritoneally with 1000 TCID₅₀ CHIKV-S27. The survival rates of the mice after challenge are depicted as Kaplan-Meier curves. Differences between the curves were determined by the log-rank test. (<b>B, C, D</b>). Vial RNA copies were determined in spleen (B), liver (C) and brain (D) samples of animals that succumbed to the infection and survivors (day 14 post challenge). (<b>E</b>) Neutralizing antibody titers were determined on day 0, 21, 63, 70, and 77. Animals were immunized on day 0 and 21 and challenged on day 63. A clear booster response is seen after challenge, where a higher response was measured in MVA-6KE1 immunized group. The results are expressed as TCID₅₀ equivalents per gram of tissue; *indicates a statistically significant result (<i>P</i><0.05) and ** indicates highly significant results (<i>P</i><0.001) as determined by the <i>Student's t test</i>.</p