Search

Leishmania elongation factor 2 (EF-2) has been previously identified as a T H 1-stimulatory protein. In this study, we assayed the protective potential of the N-terminal domain of EF-2 (N-LiEF-2, 1–357 aa) that has been predicted to contain several overlapping MHC class I and II-restricted epitopes injected in the form of dendritic cell (DC)-based vaccine. Ex vivo pulsing of DCs with the recombinant N-LiEF-2 domain along with CpG oligodeoxynucleotides (ODNs) resulted in their functional differentiation. BALB/c vaccinated with CpG-triggered DCs pulsed with N-LiEF-2 were found to be the most immune-reactive in terms of induction of DTH responses, increased T cell proliferation and IL-2 production. Moreover, vaccination induced antigen-specific T H 1 type immune response as evidenced by increased IFN-γ and TNFα levels followed by a significant increase of nitrite (NO) and reactive oxygen species (ROS) in splenocyte cultures. Vaccinated mice showed a pronounced decrease in parasite load in spleen and liver when challenged with L. infantum, increased expression of Stat1 and Tbx21 mRNA transcripts versus reduced expression of Foxp3 transcripts and were able to produce significantly elevated levels of IL-2, IFN-γ and TNFα but not IL-10 compared to non-vaccinated mice. Both antigen and parasite-specific CD4 + T and CD8 + T cells contributed to the IFN-γ production indicating that both subtypes contribute to the resistance to infection and correlated with robust nitrite generation, critical in controlling Leishmania infection. Together, these findings demonstrated the immunogenic as well as protective potential of the N-terminal domain of Leishmania EF-2 when given with CpG-triggered DCs representing a basis for the development of rationalized vaccine against leishmaniasis. © 2018 Elsevier Ltd

Visceral leishmaniasis (VL) persists as a major public health problem, and since the existing chemotherapy is far from satisfactory, development of an effective vaccine emerges as the most appropriate strategy for confronting VL. The development of an effective vaccine relies on the selection of the appropriate antigen and also the right adjuvant and/or delivery vehicle. In the present study, the protective efficacy of poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs), which were surface-modified with a TNFα-mimicking eight-amino-acid peptide (p8) and further functionalized by encapsulating soluble Leishmania infantum antigens (sLiAg) and monophosphoryl lipid A (MPLA), a TLR4 ligand, was evaluated against challenge with L. infantum parasites in BALB/c mice. Vaccination with these multifunctionalized PLGA nanoformulations conferred significant protection against parasite infection in vaccinated mice. In particular, vaccination with PLGA-sLiAg-MPLA or p8-PLGA-sLiAg NPs resulted in almost complete elimination of the parasite in the spleen for up to 4 months post-challenge. Parasite burden reduction was accompanied by antigen-specific humoral and cellular immune responses. Specifically, injection with PLGA-sLiAg-MPLA raised exclusively anti-sLiAg IgG1 antibodies post-vaccination, while in p8-PLGA-sLiAg-vaccinated mice, no antibody production was detected. However, 4 months post-challenge, in mice vaccinated with all the multifunctionalized NPs, antibody class switching towards IgG2a subtype was observed. The study of cellular immune responses revealed the increased proliferation capacity of spleen cells against sLiAg, consisting of IFNγ-producing CD4+ and CD8+ T cells. Importantly, the activation of CD8+ T cells was exclusively attributed to vaccination with PLGA NPs surface-modified with the p8 peptide. Moreover, characterization of cytokine production in vaccinated–infected mice revealed that protection was accompanied by significant increase of IFNγ and lower levels of IL-4 and IL-10 in protected mice when compared to control infected group. Conclusively, the above nanoformulations hold promise for future vaccination strategies against VL. © 2017 Margaroni et al.

Poly(lactide-co-glycolide) nanoparticles (PLGA NPs) represent a new approach for vaccine delivery due to their ability to be taken up by phagocytes and to activate immune responses. In the present study PLGA NPs were surface-modified with a TNFα mimicking peptide, and encapsulated soluble Leishmania antigens (sLiAg) and MPLA adjuvant. The synthesized PLGA NPs exhibited low cytotoxicity levels, while surface-modified NPs were more efficiently taken up by dendritic cells (DCs). The prepared nanoformulations induced maturation and functional differentiation of DCs by elevating co-stimulatory molecule levels and stimulating IL-12 and IL-10 production. Sensitized DCs promoted T cell priming, characterized by the development of mixed T cell subsets differentiation expressing Th lineage-specific transcriptional factors and cytokine genes. Moreover, PLGA NPs were biocompatible, while they were located in lymphoid organs and taken up by phagocytic cells. Our results suggest that surface-modified PLGA NPs encapsulating sLiAg and MPLA could be considered as an effective vaccine candidate against leishmaniasis. © 2016 Elsevier B.V. All rights reserved.

The virulence of a KPC-producing Klebsiella pneumoniae sequence type 258 (ST258) strain representing those circulating in Greece was assessed in a mouse septicemia model. The strain was virtually avirulent (50% lethal dose,>108 and 5×107 CFU for immunocompetent and neutropenic animals, respectively). Also, it was highly susceptible to serum killing, rapidly phagocytosed in vitro, and classified as K41, which is not among the virulent capsular types. The findings indirectly support the notion that high ST258-associated mortality is largely due to inefficient antimicrobial treatment. Copyright © 2013, American Society for Microbiology. All Rights Reserved.

Nanoparticles prepared from biodegradable polymers, such as poly(lactide-co-glycolide) (PLGA), represent a new approach for vaccine delivery due to their ability to be taken up by phagocytes and activate immune responses. In this study, fluorescently labelled bovine serum albumin (BSA-FITC)-loaded PLGA nanoparticles, of an average size ∼300 nm were prepared and examined for their ability to be taken up by bone marrow-derived dendritic cells (BM-DCs) in vitro and thus to promote their maturation and activation. The synthesized nanoparticles did not exhibit any cytotoxic or hemolytic effect and were taken up by BM-DCs efficiently, in a time and dose dependent manner. The localization of BSA-FITC loaded PLGA nanoparticles both in the acidophilic cellular compartments and the cytoplasm resulted in the maturation of BM-DCs expressing higher levels of costimulatory and MHC class II molecules in comparison to empty PLGA nanoparticles. However, the absence of IL-12 or IL-10 production indicates partial activation of BM-DCs suggesting the necessity of an adjuvant addition in order to facilitate DCs functionalization. Copyright © 2013 American Scientific Publishers. All rights reserved.

Objective: To investigate whether interleukin-1 beta (IL-1 beta) and interleukin-1 alpha (IL-1 alpha) affect the implantation rate of patients undergoing IVF-ET. Design: Follicular fluid and serum were obtained on the day of hCG administration, the day of oocyte retrieval, and the day of embryo transfer. Setting: Cellular immunology laboratory in a research institute, a high technology IVF unit in a medical center, and a university hospital. Patient(s): Thirty-three women who were undergoing IVF-ET. Main Outcome Measure(s): IL-1 beta and IL-1 alpha were measured by specific ELISA and their levels were correlated with the implantation rate. Result(s): Classification of IVF-ET patients according to their implantation rate revealed significantly higher amounts of follicular fluid IL-1 beta in the implantation versus nonimplantation cycles (68.5 +/- 24.6 pg/mL. versus 20.5 +/- 13.4 pg/mL); The difference between the level of IL-1 alpha in the two groups was not statistically significant (11.6 +/- 5.1 pg/mL versus 7.3 +/- 1.9 pg/mL). In parallel, systemic FSH/hMG-dependent IL-1 beta and IL-1 alpha production was observed in implantation cycles but not in nonimplantation cycles. Statistically significant IL-1 beta and IL-1 alpha production was observed after administration of hCG. Conclusion(s): Gonadotropins used during IVF-ET induce local and systemic production of IL-1 beta and IL-1 alpha. In addition, the implantation rate for IVF-ET patients who have detectable serum concentrations of IL-1 beta and IL-1 alpha on the day of hCG administration could be higher than the rate for IVF-ET patients who do not have detectable concentrations of these cytokines. (Fertil Steril(R) 1998;70:553-9. (C) 1998 by American Society for Reproductive Medicine.).

Objective: To study serum and follicular fluid (FF) concentrations of placenta Design: Determination in serum and FF on the day of hCG administration, day of oocyte retrieval, and on ET day of PP14 and CA-125. Setting: Second Department of Obstetrics and Gynecology of the University of Athens; Euromedica IVF Unit; and Hellenic Pasteur Institute. Patients: Thirty-three patients undergoing NF-ET divided in three groups: 8 with conception, 18 with fertilized oocytes but no conception, and 7 without fertilized oocytes. Interventions: All patients underwent an ovarian stimulation with a short protocol of GnRH analogue-pure-FSH-hMG. Three blood probes were collected from each patient, on the day of hCG administration, on retrieval day, and on ET day, respectively, whereas FF was collected on retrieval day. Main Outcome Measures: Determination in serum and FF of CA-125 and PP14. Results: On the day of oocyte retrieval, both mean values of serum PP14 and CA-125 were significantly higher in conceptional than nonconceptional cycles. On the day of ET, the mean values of serum PP14 increased significantly in conceptional cycles whereas CA-125 showed no difference. The mean concentration of PP14 in FF was significantly higher in conceptional cycles whereas there was no significant change in the mean concentration of FF CA-125. Conclusions: In conceptional cycles after IVF, PP14 increases in serum significantly from hCG day to ET day compared with nonconceptional cycles, whereas CA-125 increases from hCG day to oocyte retrieval day and decreases on ET day. In FF, PP14 was increased in conceptional cycles, whereas CA-125 in FF showed no change.