scholarly journals Miltefosine enhances infectivity of a miltefosine-resistant Leishmania infantum strain by attenuating its innate immune recognition

2021 ◽  
Vol 15 (7) ◽  
pp. e0009622
Author(s):  
Dimitri Bulté ◽  
Lieselotte Van Bockstal ◽  
Laura Dirkx ◽  
Magali Van den Kerkhof ◽  
Carl De Trez ◽  
...  
Keyword(s):  
Treatment Failure ◽  
Leishmania Infantum ◽  
Innate Immune ◽  
Oral Drug ◽  
Mammalian Host ◽  
Immune Recognition ◽  
Drug Dependency ◽  
Ifn Γ ◽  
The Impact

Background Miltefosine (MIL) is currently the only oral drug available to treat visceral leishmaniasis but its use as first-line monotherapy has been compromised by an increasing treatment failure. Despite the scarce number of resistant clinical isolates, MIL-resistance by mutations in a single aminophospholipid transporter gene can easily be selected in a laboratory environment. These mutations result in a reduced survival in the mammalian host, which can partially be restored by exposure to MIL, suggesting a kind of drug-dependency. Methodology/Principal findings To enable a combined study of the infection dynamics and underlying immunological events for differential in vivo survival, firefly luciferase (PpyRE9) / red fluorescent protein (DsRed) double-reporter strains were generated of MIL-resistant (MIL-R) and syngeneic MIL-sensitive (MIL-S) Leishmania infantum. Results in C57Bl/6 and BALB/c mice show that MIL-R parasites induce an increased innate immune response that is characterized by enhanced influx and infection of neutrophils, monocytes and dendritic cells in the liver and elevated serum IFN-γ levels, finally resulting in a less efficient establishment in liver macrophages. The elevated IFN-γ levels were shown to originate from an increased response of hepatic NK and NKT cells to the MIL-R parasites. In addition, we demonstrated that MIL could increase the in vivo fitness of MIL-R parasites by lowering NK and NKT cell activation, leading to a reduced IFN-γ production. Conclusions/Significance Differential induction of innate immune responses in the liver was found to underlie the attenuated phenotype of a MIL-R parasite and its peculiar feature of drug-dependency. The impact of MIL on hepatic NK and NKT activation and IFN-γ production following recognition of a MIL-R strain indicates that this mechanism may sustain infections with resistant parasites and contribute to treatment failure.

scholarly journals Miltefosine enhances infectivity of miltefosine-resistant Leishmania infantum by attenuating innate immune recognition

2021 ◽  
Author(s):  
Dimitri Bulté ◽  
Lieselotte Van Bockstal ◽  
Laura Dirkx ◽  
Magali Van den Kerkhof ◽  
Carl De Trez ◽  
...  
Keyword(s):  
Treatment Failure ◽  
Leishmania Infantum ◽  
Innate Immune ◽  
Clinical Isolates ◽  
Sand Fly ◽  
Oral Drug ◽  
Immune Recognition ◽  
Drug Dependency ◽  
Ifn Γ

AbstractMiltefosine (MIL) is currently the only oral drug available to treat visceral leishmaniasis but its use as first-line monotherapy has been compromised by an increasing treatment failure. Despite the scarce number of resistant clinical isolates, MIL-resistance by mutations in a single aminophospholipid transporter gene can easily be selected in a laboratory environment. These mutations result in a reduced survival in the mammalian host, which can partially be restored by exposure to MIL, suggesting a kind of drug-dependency. To enable a combined study of the infection dynamics and underlying immunological events for differential in vivo survival, firefly luciferase (PpyRE9) / red fluorescent protein (DsRed) double-reporter strains were generated of MIL-resistant (MIL-R) and syngeneic MIL-sensitive (MIL-S) Leishmania infantum. Results in C57Bl/6 and BALB/c mice show that MIL-R parasites induce an increased innate immune response that is characterized by enhanced influx and infection of neutrophils, monocytes and dendritic cells in the liver and elevated serum IFN-γ levels, finally resulting in a less efficient establishment in liver macrophages. The elevated IFN-γ levels were shown to originate from an increased response of hepatic NK and NKT cells to the MIL-R parasites. In addition, we demonstrated that MIL could increase the in vivo fitness of MIL-R parasites by lowering NK and NKT cell activation, leading to a reduced IFN-γ production. These data provide an immunological basis for the MIL-R-associated attenuated phenotype and for the peculiar drug-dependency that may constitute one of the mechanisms of treatment failure.ImportanceRecently, our laboratory demonstrated an in vivo fitness loss of experimentally selected MIL-R parasites in both the sand fly vector and vertebrate host. These findings could explain the scarce number of MIL-R clinical isolates. Surprisingly, MIL-R parasites developed a MIL-dependency which could partially rescue their fitness loss and which may constitute a mechanism of treatment failure. This research aimed to better understand the immunological basis of the attenuated phenotype and the effect of MIL on infectivity traits. Together, this study provides new insights into the complex interplay between the parasite, drug and host and discloses an immune-related mechanism of treatment failure.

The impact of Zataria multiflora Boiss extract on in vitro and in vivo Th1/Th2 cytokine (IFN-γ/IL4) balance

2013 ◽  
Vol 150 (3) ◽  
pp. 1024-1031 ◽  
Author(s):  
Mohammad Hossein Boskabady ◽  
Sakine Shahmohammadi Mehrjardi ◽  
Abadorrahim Rezaee ◽  
Houshang Rafatpanah ◽  
Sediqeh Jalali
Keyword(s):  
Zataria Multiflora ◽  
Th2 Cytokine ◽  
Ifn Γ ◽  
The Impact

scholarly journals Stem Cell Factor Enhances Interleukin-2–Mediated Expansion of Murine Natural Killer Cells In Vivo

Blood ◽  
1997 ◽  
Vol 90 (9) ◽  
pp. 3647-3653 ◽  
Author(s):  
Todd A. Fehniger ◽  
William E. Carson ◽  
Ewa Mrózek ◽  
Michael A. Caligiuri
Keyword(s):  
Nk Cells ◽  
Cell Expansion ◽  
Stem Cell Factor ◽  
Low Dose ◽  
Nk Cell ◽  
Interleukin 2 ◽  
Innate Immune ◽  
Ifn Γ

Abstract The administration of low dose interleukin-2 (IL-2) results in a selective expansion of natural killer (NK) cells in vivo, and promotes the differentiation of NK cells from hematopoietic precursor cells in vitro. We have previously shown that stem cell factor (SCF ), the ligand to the c-kit tyrosine kinase receptor, enhances IL-2–induced NK cell proliferation and differentiation in vitro. Here, we investigated the effects of SCF plus IL-2 delivered to mice in vivo. Eight-week-old C57BL/6 mice were treated with a continuous subcutaneous infusion of IL-2 (1 × 104 IU/d) plus a daily intraperitoneal dose of SCF (100 μg/kg/d), IL-2 alone, SCF alone, or vehicle alone for 8 weeks. The in vivo serum concentration of IL-2 ranged between 352 ± 12.0 pg/mL and 606 ± 9.0 pg/mL, achieving selective saturation of the high affinity IL-2 receptor, while the peak SCF serum concentration was 296 ± 13.09 ng/mL. Alone, the daily administration of SCF had no effect on the expansion of NK cells. The continuous infusion of IL-2 alone did result in a significant expansion of NK1.1+CD3− cells compared to mice treated with placebo or SCF. However, mice treated with both SCF and IL-2 showed an increase in the absolute number of NK cells that was more than twofold that seen with IL-2 alone, in the spleen (P ≤ .005), bone marrow (P ≤ .025), and blood (P < .05). NK cytotoxic activity against YAC-1 target cells was significantly higher for mice treated with SCF plus IL-2, compared to mice treated with IL-2 alone (P ≤ .0005). Interferon-γ (IFN-γ) production in cytokine-activated splenocytes was also greater for the SCF plus IL-2 group, over IL-2 treatment alone (P ≤ .01). The effect of SCF plus IL-2 on NK cell expansion was likely mediated via NK cell precursors, rather than mature NK cells. In summary, we provide the first evidence that SCF can significantly enhance expansion of functional NK cells induced by the prolonged administration of low dose IL-2 in vivo. Since the NK cell is a cytotoxic innate immune effector and a potent source of IFN-γ, this therapeutic strategy for NK cell expansion may serve to further enhance innate immune surveillance against malignant transformation and infection in the setting of cancer and/or immunodeficiency.

scholarly journals The Exopolysaccharide of Lactobacillus fermentum UCO-979C Is Partially Involved in Its Immunomodulatory Effect and Its Ability to Improve the Resistance against Helicobacter pylori Infection

2020 ◽  
Vol 8 (4) ◽  
pp. 479
Author(s):  
Valeria Garcia-Castillo ◽  
Guillermo Marcial ◽  
Leonardo Albarracín ◽  
Mikado Tomokiyo ◽  
Patricia Clua ◽  
...  
Keyword(s):  
Immune Response ◽  
Helicobacter Pylori ◽  
Gastric Mucosa ◽  
Innate Immune Response ◽  
Innate Immune ◽  
Helicobacter Pylori Infection ◽  
Beneficial Effects ◽  
Ifn Γ ◽  
H Pylori

Lactobacillus fermentum UCO-979C (Lf979C) beneficially modulates the cytokine response of gastric epithelial cells and macrophages after Helicobacter pylori infection in vitro. Nevertheless, no in vivo studies were performed with this strain to confirm its beneficial immunomodulatory effects. This work evaluated whether Lf979C improves protection against H. pylori infection in mice by modulating the innate immune response. In addition, we evaluated whether its exopolysaccharide (EPS) was involved in its beneficial effects. Lf979C significantly reduced TNF-α, IL-8, and MCP-1 and augmented IFN-γ and IL-10 in the gastric mucosa of H. pylori-infected mice. The differential cytokine profile induced by Lf979C in H. pylori-infected mice correlated with an improved reduction in the pathogen gastric colonization and protection against inflammatory damage. The purified EPS of Lf979C reduced IL-8 and enhanced IL-10 levels in the gastric mucosa of infected mice, while no effect was observed for IFN-γ. This work demonstrates for the first time the in vivo ability of Lf979C to increase resistance against H. pylori infection by modulating the gastric innate immune response. In addition, we advanced knowledge of the mechanisms involved in the beneficial effects of Lf979C by demonstrating that its EPS is partially responsible for its immunomodulatory effect.

Differential Impact of Host Derived Interleukin-18 on Regulatory and Conventional T Cell Expansion Following Murine Allogeneic Hematopoietic Cell Transplantation.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3262-3262
Author(s):  
Robert Zeiser ◽  
Elizabeth A. Zambricki ◽  
Dennis B. Leveson-Gower ◽  
Andreas Beilhack ◽  
Neeraja Kambham ◽  
...  
Keyword(s):  
Early Phase ◽  
Hematopoietic Cell Transplantation ◽  
T Helper ◽  
T Helper 1 ◽  
Graft Versus Host ◽  
In Vivo Bioluminescence Imaging ◽  
Ifn Γ ◽  
Secondary Lymphoid Organs ◽  
The Impact

Abstract Allografting as a curative approach for many hematological malignancies is hampered by the occurrence of acute graft-versus-host disease (aGvHD). Interleukin (IL)-18 stimulates T helper 1 (Th1) and Th2-mediated immune responses and has been shown to modulate aGvHD. It is still unknown whether increased IL-18 levels during aGvHD are of host or donor origin and how the absence of IL-18 impacts migration and expansion of conventional CD4+CD25− (Tconv) and CD4+CD25+ regulatory (Treg) T cells in vivo. By utilizing IL-18 gene deficient donor versus recipient animals we found that the major cytokine production during the early phase of aGVHD induction was recipient derived, while donor hematopoietic cells contributed significantly less. By generating IL-18−/ − luciferase transgenic mice we were able to investigate the impact of IL-18 on Tconv and Treg expansion and trafficking with in vivo bioluminescence imaging. While migration to secondary lymphoid organs was not significantly impacted by the absence of host IL-18, Tconv but not Treg expansion increased significantly. Absence of host IL-18 production translated into lower IFN-γ levels in the early phase after transplantation. We conclude that host derived IL-18 is a major factor for IFN-γ production that may have a protective effect on CD4+ mediated aGvHD, but is non-essential for Treg expansion in an allogeneic environment.

Gvhd Severity Is Regulated by the Adoptive Transfer Low Numbers of NKT Cells by a Mechanism Distinct From CD4+CD25+ Regulatory T Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 229-229
Author(s):  
Dennis Leveson-Gower ◽  
Janelle Olson ◽  
Emanuela I Sega ◽  
Jeanette Baker ◽  
Robert Zeiser ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Adoptive Transfer ◽  
Conflicts Of Interest ◽  
Serum Levels ◽  
Nkt Cells ◽  
Donor Type ◽  
Ifn Γ ◽  
The Impact

Abstract Abstract 229 NKT cells, a subset of which are CD1d reactive, play an important immunoregulatory role in suppressing dysfunctional immune reactions, including graft-versus-host disease (GVHD). To explore the biological activity and mechanism of donor-type NKT in suppression of GVHD, we utilized highly purified (>95%) populations of donor (C57Bl6; H-2b) NKT (DX5+TCR+CD4+) cells adoptively transferred into lethally irradiated recipient (Balb/c; H-2d) animals with T cell depleted bone marrow (TCD-BM). Highly purified (>95%) NKT cells (5.5×105) from luciferase positive (luc+) C57BL/6 mice were infused into lethally irradiated Balb/c recipients with TCD-BM(5×106) from wild-type (WT) C57BL/6 mice, and the animals were monitored by bioluminescence imaging (BLI). By day 4 after transfer, an NKT derived signal was observed in spleen and lymph node (LN) sites, and between days 7 and 10, NKT had also migrated to the skin. Total photons emitted peaked near day 25 after transplantation, followed by a steady decline. To assess the impact of donor-type NKT cells on GVHD induction by conventional CD4+ and CD8+ T cells (Tcon), we co-transferred various doses of highly purified WT NKT at day 0 with TCD-BM, followed by 5×105 luc+Tcon/animal on day 2. As few as 2.5×104 NKT cells significantly improved survival of mice receiving 5×105 Tcon. Animal survival with Tcon only was 20% and for Tcon with NKT cells was 74%(p=0.0023). In contrast to what is observed with CD4+CD25+FoxP3+ regulatory T cells (Treg), the NKT cells did not suppress Tcon proliferation assayed by both in vivo BLI and in a mixed-leukocyte reaction. Analysis of serum cytokines with or without 2.5×104 NKT, following HCT with TCD-BM and Tcon, indicated the addition of NKT cells resulted in elevated levels of INF-γ, IL-5, and IL-6 in serum; significant differences were not observed in serum levels of IL-2, IL-4, IL-10, IL-17, or TNF-α. Intracellular levels of cytokines in Tcon were analyzed from the same groups. At 8 days after HCT, mice receiving NKT had fewer TNFα-positive cells in LNs (CD4: 45% to 27%; CD8 36% to 24%); by day 11, however, TNFαa levels between groups were equivalent. IFN-γ levels, which were high in both NKT treated and untreated groups at day 8 (85%-95%), decreased significantly in NKT treated mice by day 11 (CD4: 40%; CD8: 43%), but were abundant in Tcon only mice (CD4: 78%; CD8: 80%) (p=.0001). No significant changes were found in the intracellular levels of IL-2, IL-4, IL-5, IL-10, or IL-17 of Tcon in the presence or absence of NKT cells. NKT from both IL-4 -/- and IFN-γ -/- mice were less effective at suppressing GVHD than WT NKT, implicating these cytokines in the suppressive mechanism. Finally, we found that NKT do not have a major impact on the graft-versus-tumor effect of Tcon against a luc+ BCL-1 tumor. These studies indicate that NKT persist in vivo upon adoptive transfer and suppress GVHD, even at extremely low cell numbers, which is important given the relative paucity of this cell population. The mechanisms of GVHD suppression appear to be distinct to those of Treg and involve the production of IL-4 and IFN-γ by NKT resulting in a decrease in Tcon, which produce pro-inflamatory cytokines. Disclosures: No relevant conflicts of interest to declare.

Interferon-Gamma Impairs Expansion and Hematopoietic Support of Bone Marrow Mesenchymal Stromal Cells

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 3884-3884
Author(s):  
Marieke Goedhart ◽  
Anne Cornelissen ◽  
Carlijn Kuijk ◽  
Sulima Geerman ◽  
Fernanda Pascutti ◽  
...  
Keyword(s):  
Stromal Cells ◽  
Stromal Compartment ◽  
Self Renewal ◽  
Hematopoietic Stem ◽  
Ifn Γ ◽  
Immunomodulatory Properties ◽  
Pre Treatment ◽  
The Impact

Abstract Maintenance of hematopoietic stem cells (HSCs) and regulation of their quiescence and self-renewal is critical for maintaining a lifelong supply of blood cells. The ability of HSCs to stay quiescent is thought to depend on their specific niche in the bone marrow (BM). Mesenchymal stromal cells (MSC) in the BM are multipotent stem cells that form part of the vascular HSC niche and provide micro-environmental support to HSCs both in vivo and upon expansion ex vivo. Culture-expanded MSCs also exhibit immunomodulatory properties that can be enhanced by pre-treatment with interferon-gamma (IFN-γ). BM MSC are thus attractive candidates for cellular therapy after hematopoietic stem cell transplantation, for promoting rapid hematopoietic recovery and reducing the incidence or severity of graft versus host disease. Although IFN-γ pre-treatment can improve the immunomodulatory properties of MSCs, elevated IFN-γ levels have also been associated with anemia and BM failure in multiple chronic inflammatory diseases. While the impact of IFN-γ on HSC has been elucidated in recent years, it remains largely unknown whether IFN-γ can also influence hematopoietic support by BM stromal cells. In this study, we aim to elucidate the impact of IFN-γ on hematopoietic support of BM MSC. We show that in vitro expansion of primary BM MSC cultures from healthy donors was significantly reduced in the presence of IFN-γ, and this effect could be reproduced in the BM stromal cell line MS-5. Concurrently, IFN-γ diminished the clonal capacity of BM MSC, as measured by CFU-F assays. In addition, BM MSC that were pre-stimulated with IFN-γ produced significantly lower levels of CXCL12, suggesting a loss of hematopoietic support potential. Indeed, support of CD34+ hematopoietic stem and progenitor cells (HSPC) in a co-culture assay was greatly reduced in when MSC were pre-treated with IFN-γ. To determine the impact of IFN-γ on BM MSC in vivo, we investigated the BM stromal compartment of IFN-γ AU-rich element deleted (ARE-Del) mice, which constitutively express IFN-γ in steady state conditions. FACS analysis revealed a remodeling of the BM stromal compartment in ARE-Del mice compared to littermate controls, with significantly fewer MSCs, identified as CD45-Ter119-CD31-CD51+PDGFRa+ cells. Numbers of other stromal cell subsets, such as osteoblasts and fibroblasts, were not altered. The reduction of BM MSC in ARE-Del mice coincided with a loss of quiescence in HSCs; only 35% of long term HSC (LT-HSC) in ARE-Del mice were quiescent, compared to 70% in WT mice, as determined by Ki-67 staining. Loss of quiescence in LT-HSC did not lead to increased self-renewal, but rather induced increased differentiation towards short-term HSC and multi-potent progenitors. We then sorted LT-HSC from WT and ARE-Del mice and performed in vitro HSC culture assays in the absence of IFN-γ. Absolute numbers of LT-HSC were rapidly decreased in ARE-Del compared to WT cultures after 3 and 7 days of HSC culture, while numbers of more differentiated progenitors were increased. These data indicate that an IFN-γ-mediated loss of BM MSC in ARE-Del mice leads to loss of quiescent LT-HSCs and induces a tendency towards HSC differentiation over self-renewal. In conclusion, we have shown that IFN-γ has a negative impact on expansion and hematopoietic support of BM MSC in vitro and in vivo across species. Although IFN-γ treatment enhances the immunomodulatory function of MSCs in a clinical setting, it is obvious from our data that IFN-γ impairs their HSC supporting function. These data also provide more insight in the underlying mechanism by which IFN-γ contributes to the pathogenesis of anemia and BM failure. Disclosures No relevant conflicts of interest to declare.

scholarly journals Modulation of the host microenvironment by a common non-oncolytic mouse virus leads to inhibition of plasmacytoma development through NK cell activation

2014 ◽  
Vol 95 (7) ◽  
pp. 1504-1509 ◽  
Author(s):  
Gaëtan Thirion ◽  
Anubha Saxena ◽  
Xavier Hulhoven ◽  
Dominique Markine-Goriaynoff ◽  
Jacques Van Snick ◽  
...  
Keyword(s):  
Cell Activation ◽  
Nk Cell ◽  
Infectious Agent ◽  
Innate Immune ◽  
Mouse Virus ◽  
Nk T Cells ◽  
Ifn Γ ◽  
Specific Stimulation ◽  
Micro Organisms

Although many cells undergo transformation, few actually develop into tumours, due to successful mechanisms of immunosurveillance. To investigate whether an infectious agent may play a role in this process, the growth of a plasmacytoma was investigated in mice infected by lactate dehydrogenase-elevating virus. Acutely infected animals were significantly protected against tumour development. The mechanisms responsible for this protection were analysed in mice deficient for relevant immune cells or molecules and after in vivo cell depletion. This protection by viral infection correlated with NK cell activation and with IFN-γ production. It might also be related to activation of NK/T-cells, although this remains to be proven formally. Therefore, our results indicated that infections with benign micro-organisms may protect the host against cancer development, through non-specific stimulation of the host's innate immune system and especially of NK cells.

scholarly journals Natural reassortment of a segmented RNA arbovirus illustrates plasticity of phenotype in the arthropod vector and mammalian host in vivo

2021 ◽  
Author(s):  
Christopher John Sanders ◽  
Eva Veronesi ◽  
Paulina Z Rajko-Nenow ◽  
Peter Paul Clement Mertens ◽  
Carrie Batten ◽  
...  
Keyword(s):  
Rna Viruses ◽  
Vector Model ◽  
Mammalian Host ◽  
Phenotypic Trait ◽  
Phenotypic Traits ◽  
Full Genome Sequencing ◽  
Biting Midges ◽  
Arthropod Vector ◽  
The Impact

Segmented RNA viruses are a taxonomically diverse group of 11 families that can infect plant, wildlife, livestock and human hosts. A shared feature of these viruses is the ability to exchange genome segments during co-infection of a host by a process termed 'reassortment'. Reassortment enables rapid evolutionary change, but in the case of segmented RNA viruses utilising an arthropod vector is set against the constraint of purifying selection and genetic bottlenecks imposed by replication in two evolutionarily distant hosts. In this study, we use an in vivo host: arbovirus: vector model to investigate the impact of reassortment on two phenotypic traits: vector competence and virulence in the host. Bluetongue virus (BTV) (Reoviridae) is the causative agent of bluetongue (BT), an economically important disease of domestic and wild ruminants and deer. The genome of BTV is comprised of 10 linear segments of dsRNA and the virus is transmitted between ruminants by Culicoides biting midges (Diptera: Ceratopogonidae). Five strains of BTV representing three serotypes (BTV-1, BTV-4 and BTV-8) were isolated from naturally infected ruminants in Europe and parental/reassortant lineage status assigned through full genome sequencing. Each strain was then assessed in parallel for the ability to infect Culicoides and to cause BT in sheep.  Our results demonstrate that two reassortment strains, which themselves became established in the field, had obtained high replication ability in C. sonorensis from one of the parental virus strains which allowed inferences of the genome segments conferring this phenotypic trait.

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