Bioinks from all-natural Pickering emulgels co-stabilized by cationic CNC and inclusion complexes formed by α-cyclodextrin

Direct ink writing is especially relevant to the biomedical field due to the customizable extrusion and the possibility of creating pre-designed architectures. Abundant natural polymers are sustainable and biocompatible alternatives to synthetic and persistent polymers. The printing of pure nanocellulose suspensions proves difficult due to low solid loadings, high shrinkage, as well as non-fitting rheology. Emulsion gels (emulgel) alternatives gain attention in the field owing to their favorable viscoelastic properties and the possibility of creating multiphase systems. The authors’ sulfur-free cationic cellulose nanocrystals (CNC) of low degree of substitution enable straightforward deployment in Pickering emulsions. An emulgel ink co-stabilized by cationic CNC and α-cyclodextrin is introduced as an interfacial inclusion complex. All ink components are natural and biodegradable compounds. The produced emulgel inks allow for high fidelity printing and minimum shrinkage upon drying that relaxes the need for supports, even in complex overhanging structures. A low yield stress (230–270 Pa) facilitates the inclusion of cells for biomedical applications into the formulation. The emulgel can be tuned to the desired rheological properties and be equipped with both polar and apolar compounds due to the biphasic system, making it a promising platform for biocompatible additive manufacturing

Subcutaneous Immunization with Recombinant Lactococcus lactis Expressing F1S1 Fusion Protein Induces Systemic and Mucosal Immune Responses in BALB/C Mice

Background:Lactic acid bacteria such as Lactococcus (L.) lactis are powerful tools that can function as live delivery vectors and heterologous protein expression hosts in development of novel vaccines. Pertussis toxin (PT) and filamentous hemagglutinin (FHA) are important virulence factors of Bordetella (B.) pertussis and constitute the major components of commercially available acellular pertussis (aP) vaccines. The purpose of the present study was to express F1S1 fusion protein, consisted of the N-terminal region of Si subunit from PT and FHA type 1 immunodominant domain by L. lactis and to evaluate its immunogenicity. Methods: The fusion gene composed of sequences encoding the F1s1 and the signal peptide of usp45 fragments (SECF1S1) was codon optimized for protein production in L. lactis and was synthesized and inserted in-frame inside pNZ8149 plasmid. The resulting pNZ8149-SECF1S1 construct was introduced by electroporation into L. lactis cells (LL-F1S1). BALB/c mice were subcutaneously immunized with LL-F1S1 or commercial DTaP vaccine. The immune responses were investigated. Results: The LL-F1S1-immunized mice produced significant levels of specific IFN-g compared to their respective controls and DTaP-immunized mice. The F1S1- specific IgG antibody response was lower in LL-F1S1-immunized mice while the IgG2a/IgG1 ratio was higher in this group compared to the DTaP-immunized mice. Moreover, anti-F1S1 IgA antibodies were only detected in the lung homogenates of the LL-F1S1immunized mice, suggesting the induction of a mucosal immune response. Conclusions: These results indicate the feasibility of expression of F1S1 fusion protein in L. lactis. This recombinant bacterium could induce mucosal and Th1-type systemic immune responses following subcutaneous administration

Correlation between Plasma Interleukin-3, the α

Background. Globin chain synthesis (GCS) analysis is used in the diagnosis of thalassemia. However, the wide reference range limits its use as a decisive diagnostic tool. It has been shown that α and β  globin mRNA increase through stimulation of cells by interleukin-3 (IL-3). Therefore, this study investigates the relationship between plasma IL-3 and the β/α  globin ratio. Methods. Blood samples were collected from 32 healthy participants on two occasions one month apart. GCS analysis, real-time PCR, and ELISA tests were conducted to determine the β/α  globin ratio, globin mRNA expression and stability rate, and IL-3 levels. Results. On the basis of IL-3 levels, the participants were divided in two groups. One group included participants who showed a significant increase in IL-3 as indicated by a significant rise in mean values of α, β, and γ  globin mRNA, α and β  globin, RBC, and hemoglobin. The other group included participants who showed no difference in IL-3 levels with no significant variations in the above-mentioned parameters. Conclusion. The results of this study indicate that IL-3 has an equivalent positive effect on α and β  globin chain synthesis. Therefore, IL-3 levels do not explain the wide reference range of the α/β  globin ratio

Direct Ink Writing of Biocompatible Nanocellulose and Chitosan Hydrogels for Implant Mesh Matrices

Direct ink writing via single or multihead extrusion is used to synthesize layer-by-layer (LbL) meshes comprising renewable polysaccharides. The best mechanical performance (683 ± 63 MPa modulus and 2.5 ± 0.4 MPa tensile strength) is observed for 3D printed structures with full infill density, given the role of electrostatic complexation between the oppositely charged components (chitosan and cellulose nanofibrils). The LbL structures develop an unexpectedly high wet stability that undergoes gradual weight loss at neutral and slightly acidic pH. The excellent biocompatibility and noncytotoxicity toward human monocyte/macrophages and controllable shrinkage upon solvent exchange make the cellular meshes appropriate for use as biomedical implants.Peer reviewe

Recombinant forms of Leishmania amazonensis excreted/secreted promastigote surface antigen (PSA) induce protective immune responses in dogs

International audiencePreventive vaccination is a highly promising strategy for interrupting leishmaniasis transmission that can, additionally, contribute to elimination. A vaccine formulation based on naturally excreted secreted (ES) antigens was prepared from L. infantum promastigote culture supernatant. This vaccine achieved successful results in Phase III trials and was licensed and marketed as CaniLeish. We recently showed that newly identified ES promastigote surface antigen (PSA), from both viable promastigotes and axenically-grown amastigotes, represented the major constituent and the highly immunogenic antigen of L. infantum and L. amazonensis ES products. We report here that three immunizations with either the recombi-nant ES LaPSA-38S (rPSA) or its carboxy terminal part LaPSA-12S (Cter-rPSA), combined with QA-21 as adjuvant, confer high levels of protection in naive L. infantum-infected Beagle dogs, as checked by bone marrow parasite absence in respectively 78.8% and 80% of vaccinated dogs at 6 months post-challenge. The parasite burden in infected vaccinated dogs was significantly reduced compared to placebo group, as measured by q-PCR. Moreover, our results reveal humoral and cellular immune response clear-cut differences between vaccinated and control dogs. An early increase in specific IgG2 antibodies was observed in rPSA/QA-21-and Cter-rPSA/QA-21-immunized dogs only. They were found functionally active in vitro and were highly correlated with vaccine protection. In vaccinated protected dogs, IFN-γ and NO productions, as well as anti-leishmanial macrophage activity, were increased. These data strongly suggest that ES PSA or its carboxy-terminal part, in recom-binant forms, induce protection in a canine model of zoonotic visceral leishmaniasis by inducing a Th1-dominant immune response and an appropriate specific antibody response. These data suggest that they could be considered as important active components in vaccine candidates

In Vitro Evaluation of a Soluble Leishmania Promastigote Surface Antigen as a Potential Vaccine Candidate against Human Leishmaniasis

International audiencePSA (Promastigote Surface Antigen) belongs to a family of membrane-bound and secreted proteins present in severalLeishmania (L.) species. PSA is recognized by human Th1 cells and provides a high degree of protection in vaccinated mice.We evaluated humoral and cellular immune responses induced by a L. amazonensis PSA protein (LaPSA-38S) produced in aL. tarentolae expression system. This was done in individuals cured of cutaneous leishmaniasis due to L. major (CCLm) or L.braziliensis (CCLb) or visceral leishmaniasis due to L. donovani (CVLd) and in healthy individuals. Healthy individuals weresubdivided into immune (HHR-Lm and HHR-Li: Healthy High Responders living in an endemic area for L. major or L. infantuminfection) or non immune/naive individuals (HLR: Healthy Low Responders), depending on whether they produce high orlow levels of IFN-c in response to Leishmania soluble antigen. Low levels of total IgG antibodies to LaPSA-38S were detectedin sera from the studied groups. Interestingly, LaPSA-38S induced specific and significant levels of IFN-c, granzyme B and IL-10 in CCLm, HHR-Lm and HHR-Li groups, with HHR-Li group producing TNF-a in more. No significant cytokine response wasobserved in individuals immune to L. braziliensis or L. donovani infection. Phenotypic analysis showed a significant increasein CD4+ T cells producing IFN-c after LaPSA-38S stimulation, in CCLm. A high positive correlation was observed between thepercentage of IFN-c-producing CD4+ T cells and the released IFN-c. We showed that the LaPSA-38S protein was able toinduce a mixed Th1 and Th2/Treg cytokine response in individuals with immunity to L. major or L. infantum infectionindicating that it may be exploited as a vaccine candidate. We also showed, to our knowledge for the first time, the capacityof Leishmania PSA protein to induce granzyme B production in humans with immunity to L. major and L. infantum infectio

Health concerns of various nanoparticles: A review of their in vitro and in vivo toxicity

Nanoparticles (NPs) are currently used in diagnosis and treatment of many human diseases, including autoimmune diseases and cancer. However, cytotoxic effects of NPs on normal cells and living organs is a severe limiting factor that hinders their use in clinic. In addition, diversity of NPs and their physico-chemical properties, including particle size, shape, surface area, dispersity and protein corona effects are considered as key factors that have a crucial impact on their safe or toxicological behaviors. Current studies on toxic effects of NPs are aimed to identify the targets and mechanisms of their side effects, with a focus on elucidating the patterns of NP transport, accumulation, degradation, and elimination, in both in vitro and in vitro models. NPs can enter the body through inhalation, skin and digestive routes. Consequently, there is a need for reliable information about effects of NPs on various organs in order to reveal their efficacy and impact on health. This review covers the existing knowledge base on the subject that hopefully prepares us better to address these challenges. © 2018 by the authors. Licensee MDPI, Basel, Switzerland

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

CD8+ T Cells as a Source of IFN-γ Production in Human Cutaneous Leishmaniasis

Cutaneous leishmaniasis (CL) is usually a self-healing skin lesion caused by different species of Leishmania parasite. Resistance and susceptibility of mice to Leishmania major infection is associated with two types of CD4+ T lymphocytes development: Th1 type response with production of cytokine IFN-γ is associated with resistance, whereas Th2 type response with production of cytokines IL-4 and IL-5 is associated with susceptibility. A clear Th1/Th2 dichotomy similar to murine model is not defined in human leishmaniasis and we need as much information as possible to define marker(s) of protection. We purified CD4+/CD8+ T cells, stimulated them with Leishmania antigens and analysed gene and protein expression of Th1/Th2 cytokines in volunteers with a history of self-healing CL who are presumed to be protected against further Leishmania infection. We have seen significant upregulation of IFN-γ gene expression and high IFN-γ production in the Leishmania stimulated CD4+ T cells and CD8+ T cells. We concluded that both antigen-specific IFN-γ producing CD4+ Th1 cells and IFN-γ producing CD8+ T cells contribute to the long term protection in individuals with a history of CL. This proves the importance of CD8+ T cells as a source of IFN-γ in Th1-like immune responses

High-Throughput Analysis of Synthetic Peptides for the Immunodiagnosis of Canine Visceral Leishmaniasis

Globally, the number of new human cases of visceral leishmaniasis (VL) is estimated to be approximately 500,000 per year. This is the most severe of all forms of leishmaniasis, and the zoonotic form of VL, caused by Leishmania infantum (also known as Leishmania chagasi), represents 20% of human visceral leishmaniasis worldwide; additionally, its prevalence is increasing in urban and peri-urban areas of the tropics. In Brazil, the identification and elimination of infected dogs, which act as a reservoir for Leishmania parasites, is a control measure employed in addition to the use of insecticides against the vectors and the identification and treatment of infected humans. Currently, the diagnostic methods employed to identify infected animals are not able to detect all of these dogs, which compromises the effectiveness of control measures. Moreover, one of the most important issues in controlling VL is the difficulty of diagnosing asymptomatic dogs, which act as parasite reservoirs. Therefore, to contribute to the improvement of the diagnostic methods for CVL, we aimed to identify and characterize new antigens that were more sensitive and specific and could be applied in epidemiologic surveys