The formation of Fe-Cu composite based on bimetallic nanoparticles

In this paper we suggest a new method of producing a Fe-28 wt% Cu composite by compacting and subsequent sintering of bimetallic nanoparticles made of metals with limited mutual miscibility: iron and copper. The influence of the temperature of annealing on the structure and phase composition of consolidated composite samples has been analyzed. It has been shown that annealing in the temperature range of 200–400 °C induces the processes of low-temperature sintering of copper and iron. These processes are accompanied by the growth of the size of coherent scattering regions and the separation of the metallic components of nanoparticles. During thermal treatment in the range between 400 and 600 °C, adjacent sidewalls of large particles are welded together and large pores emerge in the sample. Further temperature increases cause the sample to shrink and the pores to become smaller. The consolidation of bimetallic nanoparticles consisting of iron and copper and their subsequent sintering allows for obtaining volumetric composites that have homogeneous structure without distinct macroscopic separation of phases as well as high strength characteristics.Russian Science Foundatio

Induction of Protective CD4+ T Cell-Mediated Immunity by a Leishmania Peptide Delivered in Recombinant Influenza Viruses

The available evidence suggests that protective immunity to Leishmania is achieved by priming the CD4+ Th1 response. Therefore, we utilised a reverse genetics strategy to generate influenza A viruses to deliver an immunogenic Leishmania peptide. The single, immunodominant Leishmania-specific LACK158–173 CD4+ peptide was engineered into the neuraminidase stalk of H1N1 and H3N2 influenza A viruses. These recombinant viruses were used to vaccinate susceptible BALB/c mice to determine whether the resultant LACK158–173-specific CD4+ T cell responses protected against live L. major infection. We show that vaccination with influenza-LACK158–173 triggers LACK158–173-specific Th1-biased CD4+ T cell responses within an appropriate cytokine milieu (IFN-γ, IL-12), essential for the magnitude and quality of the Th1 response. A single intraperitoneal exposure (non-replicative route of immunisation) to recombinant influenza delivers immunogenic peptides, leading to a marked reduction (2–4 log) in parasite burden, albeit without reduction in lesion size. This correlated with increased numbers of IFN-γ-producing CD4+ T cells in vaccinated mice compared to controls. Importantly, the subsequent prime-boost approach with a serologically distinct strain of influenza (H1N1->H3N2) expressing LACK158–173 led to a marked reduction in both lesion size and parasite burdens in vaccination trials. This protection correlated with high levels of IFN-γ producing cells in the spleen, which were maintained for 6 weeks post-challenge indicating the longevity of this protective effector response. Thus, these experiments show that Leishmania-derived peptides delivered in the context of recombinant influenza viruses are immunogenic in vivo, and warrant investigation of similar vaccine strategies to generate parasite-specific immunity