Negative-index bi-anisotropic photonic metamaterial fabricated by direct laser writing and silver shadow evaporation

We present the blueprint for a novel negative-index metamaterial. This structure is fabricated via three-dimensional two-photon direct laser writing and silver shadow evaporation. The comparison of measured linear optical spectra with theory shows good agreement and reveals a negative real part of the refractive index at around 3.85 micrometer wavelength - despite the fact that the metamaterial structure is bi-anisotropic due to the lack of inversion symmetry along its surface normal.Comment: 8 pages, 3 figure

Polyclonal Antibodies Derived from Transchromosomic Bovines Vaccinated with the Recombinant F1-V Vaccine Increase Bacterial Opsonization In Vitro and Protect Mice from Pneumonic Plague

Plague is an ancient disease that continues to be of concern to both the public health and biodefense research communities. Pneumonic plague is caused by hematogenous spread of Yersinia pestis bacteria from a ruptured bubo to the lungs or by directly inhaling aerosolized bacteria. The fatality rate associated with pneumonic plague is significant unless effective antibiotic therapy is initiated soon after an early and accurate diagnosis is made. As with all bacterial pathogens, drug resistance is a primary concern when developing strategies to combat these Yersinia pestis infections in the future. While there has been significant progress in vaccine development, no FDA-approved vaccine strategy exists; thus, other medical countermeasures are needed. Antibody treatment has been shown to be effective in animal models of plague. We produced fully human polyclonal antibodies in transchromosomic bovines vaccinated with the recombinant F1-V plague vaccine. The resulting human antibodies opsonized Y. pestis bacteria in the presence of RAW264.7 cells and afforded significant protection to BALB/c mice after exposure to aerosolized Y. pestis. These data demonstrate the utility of this technology to produce large quantities of non-immunogenic anti-plague human antibodies to prevent or possibly treat pneumonic plague in human

Functional assays to screen and select monoclonal antibodies that target Yersinia pestis

Yersinia pestis is a gram-negative bacterium that causes plague in animals and humans. Depending on the route of disease transmission, the bacterium can cause an acute, often fatal disease that has a narrow window for treatment with antibiotics. Additionally, antibiotic resistant strains have been identified, emphasizing the need for novel treatments. Antibody therapy is an appealing option that can direct the immune system to clear bacterial infections. Advances in biotechnology have made both engineering and producing antibodies easier and more affordable. In this study, two screening assays were optimized to evaluate the ability of antibodies to promote phagocytosis of Y. pestis by macrophages and to induce a cytokine signature in vitro that may be predictive of protection in vivo. We evaluated a panel of 21 mouse monoclonal antibodies targeting either the anti-phagocytic capsule F1 protein or the LcrV antigen, which is part of the type 3 secretion system that facilitates translocation of virulence factors into the host cell, using two functional assays. Anti-F1 and anti-LcrV monoclonal antibodies both increased bacterial uptake by macrophages, with greater uptake observed in the presence of antibodies that were protective in the mouse pneumonic plague model. In addition, the protective anti-F1 and anti-LcrV antibodies produced unique cytokine signatures that were also associated with in vivo protection. These antibody-dependent characteristics from in vitro functional assays will be useful in down-selecting efficacious novel antibodies that can be used for treatment of plague

Presentation_1_Live attenuated vaccines and layered defense strategies to combat infections caused by nonencapsulated Yersinia pestis.pptx

IntroductionPlague is an ancient disease caused by Yersinia pestis, a widely disseminated Tier 1 pathogen that poses significant public health and biothreat risks. The rapid course and high mortality of pneumonic plague limit the efficacy of antibiotic treatment and mandate the need for an effective, licensed, and readily available vaccine. New candidate vaccines are being developed; however, their efficacy in nonhuman primates, optimal vaccination schedule and immune response, duration of protection, and breadth of coverage against various virulent strains are inadequately understood. In the current work, we explored homologous and heterologous vaccination schemes using the sensitive BALB/c mouse models of bubonic and pneumonic plague challenged with Y. pestis strain C12. This strain, a derivative of the wild-type strain CO92, lacks the anti-phagocytic F1 capsule yet remains highly virulent. Protection against such nonencapsulated strains has been particularly elusive.MethodsWe tested the efficacy of live attenuated vaccine (LAV) derivatives of Y. pestis CO92 or C12 with a deletion of a type 3 secretion-associated gene (ΔyscN) or the pgm pigmentation locus, and they were cured of the pPst (PCP1) plasmid (CO92 pgm− pPst−). The LAVs were evaluated alone or accompanied by a dose of a protein subunit vaccine (rF1V or rV).ResultsThe most protective and immunogenic vaccination scheme, as tested under a variety of conditions in bubonic and pneumonic plague models, was heterologous vaccination with a LAV and the recombinant rF1V or rV protein subunit vaccine. Furthermore, in the heterologous scheme, different LAVs and subunit vaccines could be substituted, affording flexibility in vaccine component selection. We also evaluated a novel intervention strategy consisting of vaccination and post-exposure antibiotic treatment. The layering of vaccination with the LAVs and post-exposure treatment with streptomycin was synergistic, extending the time after the Y. pestis C12 challenge when treatment remained effective and affording a sparing of antibiotics.ConclusionThe current work defined effective and flexible vaccination and treatment interventions that successfully prevented lethal infection with virulent, nonencapsulated Y. pestis.</p

Table_2_Live attenuated vaccines and layered defense strategies to combat infections caused by nonencapsulated Yersinia pestis.xlsx

IntroductionPlague is an ancient disease caused by Yersinia pestis, a widely disseminated Tier 1 pathogen that poses significant public health and biothreat risks. The rapid course and high mortality of pneumonic plague limit the efficacy of antibiotic treatment and mandate the need for an effective, licensed, and readily available vaccine. New candidate vaccines are being developed; however, their efficacy in nonhuman primates, optimal vaccination schedule and immune response, duration of protection, and breadth of coverage against various virulent strains are inadequately understood. In the current work, we explored homologous and heterologous vaccination schemes using the sensitive BALB/c mouse models of bubonic and pneumonic plague challenged with Y. pestis strain C12. This strain, a derivative of the wild-type strain CO92, lacks the anti-phagocytic F1 capsule yet remains highly virulent. Protection against such nonencapsulated strains has been particularly elusive.MethodsWe tested the efficacy of live attenuated vaccine (LAV) derivatives of Y. pestis CO92 or C12 with a deletion of a type 3 secretion-associated gene (ΔyscN) or the pgm pigmentation locus, and they were cured of the pPst (PCP1) plasmid (CO92 pgm− pPst−). The LAVs were evaluated alone or accompanied by a dose of a protein subunit vaccine (rF1V or rV).ResultsThe most protective and immunogenic vaccination scheme, as tested under a variety of conditions in bubonic and pneumonic plague models, was heterologous vaccination with a LAV and the recombinant rF1V or rV protein subunit vaccine. Furthermore, in the heterologous scheme, different LAVs and subunit vaccines could be substituted, affording flexibility in vaccine component selection. We also evaluated a novel intervention strategy consisting of vaccination and post-exposure antibiotic treatment. The layering of vaccination with the LAVs and post-exposure treatment with streptomycin was synergistic, extending the time after the Y. pestis C12 challenge when treatment remained effective and affording a sparing of antibiotics.ConclusionThe current work defined effective and flexible vaccination and treatment interventions that successfully prevented lethal infection with virulent, nonencapsulated Y. pestis.</p

Table_1_Live attenuated vaccines and layered defense strategies to combat infections caused by nonencapsulated Yersinia pestis.xlsx

IntroductionPlague is an ancient disease caused by Yersinia pestis, a widely disseminated Tier 1 pathogen that poses significant public health and biothreat risks. The rapid course and high mortality of pneumonic plague limit the efficacy of antibiotic treatment and mandate the need for an effective, licensed, and readily available vaccine. New candidate vaccines are being developed; however, their efficacy in nonhuman primates, optimal vaccination schedule and immune response, duration of protection, and breadth of coverage against various virulent strains are inadequately understood. In the current work, we explored homologous and heterologous vaccination schemes using the sensitive BALB/c mouse models of bubonic and pneumonic plague challenged with Y. pestis strain C12. This strain, a derivative of the wild-type strain CO92, lacks the anti-phagocytic F1 capsule yet remains highly virulent. Protection against such nonencapsulated strains has been particularly elusive.MethodsWe tested the efficacy of live attenuated vaccine (LAV) derivatives of Y. pestis CO92 or C12 with a deletion of a type 3 secretion-associated gene (ΔyscN) or the pgm pigmentation locus, and they were cured of the pPst (PCP1) plasmid (CO92 pgm− pPst−). The LAVs were evaluated alone or accompanied by a dose of a protein subunit vaccine (rF1V or rV).ResultsThe most protective and immunogenic vaccination scheme, as tested under a variety of conditions in bubonic and pneumonic plague models, was heterologous vaccination with a LAV and the recombinant rF1V or rV protein subunit vaccine. Furthermore, in the heterologous scheme, different LAVs and subunit vaccines could be substituted, affording flexibility in vaccine component selection. We also evaluated a novel intervention strategy consisting of vaccination and post-exposure antibiotic treatment. The layering of vaccination with the LAVs and post-exposure treatment with streptomycin was synergistic, extending the time after the Y. pestis C12 challenge when treatment remained effective and affording a sparing of antibiotics.ConclusionThe current work defined effective and flexible vaccination and treatment interventions that successfully prevented lethal infection with virulent, nonencapsulated Y. pestis.</p