In vivo generation of human dendritic cell subsets by Flt3 ligand

Blood ◽  
2000 ◽  
Vol 96 (3) ◽  
pp. 878-884 ◽  
Author(s):  
Eugene Maraskovsky ◽  
Elizabeth Daro ◽  
Eileen Roux ◽  
Mark Teepe ◽  
Charlie R. Maliszewski ◽  
...  
Keyword(s):  
T Cell Immunity ◽  
Human Dendritic Cell ◽  
Flt3 Ligand ◽  
Healthy Human ◽  
Cell Immunity ◽  
Human Volunteers ◽  
Immune Response Regulation ◽  
Dendritic Cell Subsets

Abstract Dendritic cells (DCs) represent a family of ontogenically distinct leukocytes involved in immune response regulation. The ability of DCs to stimulate T-cell immunity has led to their use as vectors for immunotherapy vaccines. However, it is unclear whether and to what degree in vitro–generated DCs are representative of DCs that develop in vivo. Treatment of mice with human Flt3 ligand (FL) dramatically increases the number of DCs. We report here that administration of FL to healthy human volunteers increased the number of circulating CD11c+ IL-3Rlow DC (mean 44-fold) and CD11c− IL-3Rhigh DC precursors (mean 12-fold). Moreover, the CD11c+ DCs were efficient stimulators of T cells in vitro. Thus, FL can expand the number of circulating, functionally competent human DCs in vivo.

In vivo generation of human dendritic cell subsets by Flt3 ligand

Blood ◽  
2000 ◽  
Vol 96 (3) ◽  
pp. 878-884 ◽  
Author(s):  
Eugene Maraskovsky ◽  
Elizabeth Daro ◽  
Eileen Roux ◽  
Mark Teepe ◽  
Charlie R. Maliszewski ◽  
...  
Keyword(s):  
T Cell Immunity ◽  
Human Dendritic Cell ◽  
Flt3 Ligand ◽  
Healthy Human ◽  
Cell Immunity ◽  
Human Volunteers ◽  
Immune Response Regulation ◽  
Dendritic Cell Subsets

Dendritic cells (DCs) represent a family of ontogenically distinct leukocytes involved in immune response regulation. The ability of DCs to stimulate T-cell immunity has led to their use as vectors for immunotherapy vaccines. However, it is unclear whether and to what degree in vitro–generated DCs are representative of DCs that develop in vivo. Treatment of mice with human Flt3 ligand (FL) dramatically increases the number of DCs. We report here that administration of FL to healthy human volunteers increased the number of circulating CD11c+ IL-3Rlow DC (mean 44-fold) and CD11c− IL-3Rhigh DC precursors (mean 12-fold). Moreover, the CD11c+ DCs were efficient stimulators of T cells in vitro. Thus, FL can expand the number of circulating, functionally competent human DCs in vivo.

scholarly journals ABT-378, a Highly Potent Inhibitor of the Human Immunodeficiency Virus Protease

1998 ◽  
Vol 42 (12) ◽  
pp. 3218-3224 ◽  
Author(s):  
Hing L. Sham ◽  
Dale J. Kempf ◽  
Akhteruzammen Molla ◽  
Kennan C. Marsh ◽  
Gondi N. Kumar ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Protease Inhibitor ◽  
Response To Therapy ◽  
Hiv Protease ◽  
Healthy Human ◽  
Human Volunteers ◽  
Immunodeficiency Virus ◽  
Potent Protease Inhibitor

ABSTRACT The valine at position 82 (Val 82) in the active site of the human immunodeficiency virus (HIV) protease mutates in response to therapy with the protease inhibitor ritonavir. By using the X-ray crystal structure of the complex of HIV protease and ritonavir, the potent protease inhibitor ABT-378, which has a diminished interaction with Val 82, was designed. ABT-378 potently inhibited wild-type and mutant HIV protease (Ki = 1.3 to 3.6 pM), blocked the replication of laboratory and clinical strains of HIV type 1 (50% effective concentration [EC50], 0.006 to 0.017 μM), and maintained high potency against mutant HIV selected by ritonavir in vivo (EC50, ≤0.06 μM). The metabolism of ABT-378 was strongly inhibited by ritonavir in vitro. Consequently, following concomitant oral administration of ABT-378 and ritonavir, the concentrations of ABT-378 in rat, dog, and monkey plasma exceeded the in vitro antiviral EC50 in the presence of human serum by >50-fold after 8 h. In healthy human volunteers, coadministration of a single 400-mg dose of ABT-378 with 50 mg of ritonavir enhanced the area under the concentration curve of ABT-378 in plasma by 77-fold over that observed after dosing with ABT-378 alone, and mean concentrations of ABT-378 exceeded the EC50 for >24 h. These results demonstrate the potential utility of ABT-378 as a therapeutic intervention against AIDS.

scholarly journals Comparative Bioavailabilitv Studv of Two Brands of Terbutaline Sulphate Tablets in Healthy Human Volunteers

2004 ◽  
Vol 72 (3) ◽  
pp. 227-237
Author(s):  
Nahla S. Barakat ◽  
Nawal M. Khalafallah ◽  
Said A. Khalil
Keyword(s):  
Single Dose ◽  
Reference Product ◽  
Hplc Method ◽  
Fasting State ◽  
Unchanged Drug ◽  
Healthy Human ◽  
Terbutaline Sulphate ◽  
Human Volunteers

The purpose of this study was to evaluate the bioavailability of locally produced 2.5 mg terbutaline sulphate tablets (brand A ) relative to a reference product, Bricanyl 2.5 mg tablets (brand 6). The study was a single dose 5 mg randomized crossover one in 15 healthy volunteers in the fasting state. Urine was collected at intervals of 24 h. Total terbutaline excreted in urine as unchanged drug and as conjugates (sulphate and glucuronide) was determined by a developed and validated HPLC method. In-vitro characteristics of both brands were similar. Based on percent of the dose excreted in urine, the oral bioavailability ranged from 33.5% to 75.8% for both brands. Statistics were applied to judge bioequivalence according to USP 24 in-vivo bioequivalence guidance. Results indicated that brand A and B were bioequivalent and hence interchangeable in medical practice.

scholarly journals The complement inhibitory protein DAF (CD55) suppresses T cell immunity in vivo

2005 ◽  
Vol 201 (4) ◽  
pp. 567-577 ◽  
Author(s):  
Jianuo Liu ◽  
Takashi Miwa ◽  
Brendan Hilliard ◽  
Youhai Chen ◽  
John D. Lambris ◽  
...  
Keyword(s):  
T Cell ◽  
Vaccine Development ◽  
T Cell Immunity ◽  
Cell Secretion ◽  
Inhibitory Protein ◽  
Cell Immunity ◽  
Ifn Γ ◽  
Eae Model

Decay-accelerating factor ([DAF] CD55) is a glycosylphosphatidylinositol-anchored membrane inhibitor of complement with broad clinical relevance. Here, we establish an additional and unexpected role for DAF in the suppression of adaptive immune responses in vivo. In both C57BL/6 and BALB/c mice, deficiency of the Daf1 gene, which encodes the murine homologue of human DAF, significantly enhanced T cell responses to active immunization. This phenotype was characterized by hypersecretion of interferon (IFN)-γ and interleukin (IL)-2, as well as down-regulation of the inhibitory cytokine IL-10 during antigen restimulation of lymphocytes in vitro. Compared with wild-type mice, Daf1−/− mice also displayed markedly exacerbated disease progression and pathology in a T cell–dependent experimental autoimmune encephalomyelitis (EAE) model. However, disabling the complement system in Daf1−/− mice normalized T cell secretion of IFN-γ and IL-2 and attenuated disease severity in the EAE model. These findings establish a critical link between complement and T cell immunity and have implications for the role of DAF and complement in organ transplantation, tumor evasion, and vaccine development.

scholarly journals Assessment of Drug Delivery Kinetics to Epidermal Targets In Vivo

2021 ◽  
Vol 23 (3) ◽  
Author(s):  
M. Hoppel ◽  
M. A. M. Tabosa ◽  
A. L. Bunge ◽  
M. B. Delgado-Charro ◽  
R. H. Guy
Keyword(s):  
Experimental Approach ◽  
Input Function ◽  
Drug Uptake ◽  
Tape Stripping ◽  
Healthy Human ◽  
Topical Product ◽  
Human Volunteers ◽  
Dermal Pharmacokinetics

AbstractIt has proven challenging to quantify ‘drug input’ from a formulation to the viable skin because the epidermal and dermal targets of topically applied drugs are difficult, if not impossible, to access in vivo. Defining the drug input function to the viable skin with a straightforward and practical experimental approach would enable a key component of dermal pharmacokinetics to be characterised. It has been hypothesised that measuring drug uptake into and clearance from the stratum corneum (SC) by tape-stripping allows estimation of a topical drug’s input function into the viable tissue. This study aimed to test this idea by determining the input of nicotine and lidocaine into the viable skin, following the application of commercialised transdermal patches to healthy human volunteers. The known input rates of these delivery systems were used to validate and assess the results from the tape-stripping protocol. The drug input rates from in vivo tape-stripping agreed well with the claimed delivery rates of the patches. The experimental approach was then used to determine the input of lidocaine from a marketed cream, a typical topical product for which the amount of drug absorbed has not been well-characterised. A significantly higher delivery of lidocaine from the cream than from the patch was found. The different input rates between drugs and formulations in vivo were confirmed qualitatively and quantitatively in vitro in conventional diffusion cells using dermatomed abdominal pig skin.

IN VITRO AND IN VIVO INVESTIGATIONS ON THE EFFECTS OF CYCLOSPORINE ON HUMAN DENDRITIC CELL SUBSETS

2004 ◽  
Vol 78 ◽  
pp. 601-602
Author(s):  
S Ciesek ◽  
B P. Ringe ◽  
C P. Strassburg ◽  
J Klempnauer ◽  
M P. Manns ◽  
...  
Keyword(s):  
Dendritic Cell ◽  
Human Dendritic Cell ◽  
Dendritic Cell Subsets

scholarly journals The safety profile of Bald’s eyesalve for the treatment of bacterial infections

2020 ◽  
Author(s):  
Blessing O Anonye ◽  
Valentine Nweke ◽  
Jessica Furner-Pardoe ◽  
Rebecca Gabrilska ◽  
Afshan Rafiq ◽  
...  
Keyword(s):  
Topical Application ◽  
Safety Profile ◽  
Bacterial Infections ◽  
Ex Vivo ◽  
Corneal Opacity ◽  
Healthy Human ◽  
Patch Tests ◽  
Human Volunteers

AbstractThe rise in antimicrobial resistance has prompted the development of alternatives, such as plant-derived compounds, to combat bacterial infections. Bald’s eyesalve, a remedy used in the Early Medieval period, has previously been shown to have efficacy against Staphylococcus aureus grown in an in vitro model of soft tissue infection. This remedy also had bactericidal activity against methicillin-resistant S. aureus (MRSA) in a chronic mouse wound. However, the safety profile of Bald’s eyesalve has not yet been demonstrated, and this is vital before testing in humans. Here, we determined the safety potential of Bald’s eyesalve using in vitro, ex vivo, and in vivo models representative of skin or eye infections. We also confirmed that Bald’s eyesalve is active against an important eye pathogen, Neisseria gonorrhoeae. Low levels of cytotoxicity were observed in eyesalve-treated cell lines representative of skin and immune cells. Results from a bovine corneal opacity and permeability test demonstrated slight irritation to the cornea that resolved within 10 minutes. The slug mucosal irritation assay revealed that a low level of mucus was secreted by slugs exposed to eyesalve, indicating mild mucosal irritation. We obtained promising results from mouse wound closure experiments; no visible signs of irritation or inflammation were observed. Our results suggest that Bald’s eyesalve could be tested further on human volunteers to assess safety for topical application against bacterial infections.ImportanceAlternative treatment for bacterial infections are needed to combat the ever increasing repertoire of bacteria resistant to antibiotics. A medieval plant-based remedy, Bald’s eyesalve, shows promise as a substitute for the treatment of these infections. For any substance to be effective in the treatment of bacterial infections in humans, it is important to consider the safety profile. This is a key consideration in order to have the necessary regulatory approval. We demonstrate the safety profile of Bald’s eyesalve using a variety of models, including whole-organ and whole-animal models. Our results show that Bald’s eyesalve is mildly toxic to cultured human cells, but potentially suitable for patch tests on healthy human volunteers to assess safety for later clinical trials. Our work has the potential to transform the management of diseases caused by bacterial infections, such as diabetic foot ulcers, through topical application of a natural product cocktail based on Bald’s eyesalve.

Functional comparison of DCs generated in vivo with Flt3 ligand or in vitro from blood monocytes: differential regulation of function by specific classes of physiologic stimuli

Blood ◽  
2003 ◽  
Vol 102 (5) ◽  
pp. 1753-1763 ◽  
Author(s):  
Michael Jefford ◽  
Max Schnurr ◽  
Tracey Toy ◽  
Kelly-Anne Masterman ◽  
Amanda Shin ◽  
...  
Keyword(s):  
T Cell ◽  
Cytotoxic T Lymphocyte ◽  
Lymphoid Tissues ◽  
Flt3 Ligand ◽  
Blood Monocytes ◽  
Soluble Cd40 Ligand ◽  
Proinflammatory Mediators ◽  
Cell Immunity

AbstractDendritic cells (DCs) are a family of leukocytes that initiate T- and B-cell immunity against pathogens. Migration of antigen-loaded DCs from sites of infection into draining lymphoid tissues is fundamental to the priming of T-cell immune responses. In humans, the major peripheral blood DC (PBDC) types, CD1c+ DCs and interleukin 3 receptor–positive (IL-3R+) plasmacytoid DCs, are significantly expanded in vivo with the use of Flt3 ligand (FL). DC-like cells can also be generated from monocyte precursors (MoDCs). A detailed comparison of the functional potential of these types of DCs (in an autologous setting) has yet to be reported. Here, we compared the functional capacity of FL-expanded CD1c+ PBDCs with autologous MoDCs in response to 3 different classes of stimuli: (1) proinflammatory mediators, (2) soluble CD40 ligand trimer (CD40L), and (3) intact bacteria (Escherichia coli). Significant differences in functional capacities were found with respect to changes in phenotype, migratory capacity, cytokine secretion, and T-cell stimulation. MoDCs required specific stimuli for the expression of functions. They responded vigorously to CD40L or E coli, expressing cytokines known to regulate interferon-γ (IFN-γ) in T cells (IL-12p70, IL-18, and IL-23), but required prostaglandin E2 (PGE2) during stimulation to migrate to chemokines. In contrast, PBDCs matured in response to minimal stimulation, rapidly acquired migratory function in the absence of PGE2-containing stimuli, and were low cytokine producers. Interestingly, both types of DCs were equivalent with respect to stimulation of allogeneic T-cell proliferation and presentation of peptides to cytotoxic T lymphocyte (CTL) lines. These distinct differences are of particular importance when considering the choice of DC types for clinical applications.

Antibody Targeting of Activated Dendritic Cells Prevents AGVHD and Preserves T Cell Immunity.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3240-3240
Author(s):  
Hannah Cullup ◽  
John Wilson ◽  
Alison M. Rice ◽  
Anne M. Dickinson ◽  
David J. Munster ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Lymphocytes ◽  
T Cell Immunity ◽  
Mouse Serum ◽  
Human Pbmc ◽  
Cell Immunity ◽  
Life Threatening

Abstract AGVHD is a life threatening complication of allogeneic HSCT, initiated by host and donor DC stimulation of donor T lymphocytes. Current AGVHD prophylaxis targets T lymphocytes, compromising anti-viral and therapeutic anti-leukemic responses. The presence of activated blood DC predicts for clinical AGVHD and we predict that a new strategy targeting therapy to activated DC should prevent alloimmune induction of AGVHD but preserve protective T cell immune responses. CD83 is a cell surface molecule expressed by activated DC. Having shown that a rabbit polyclonal antibody to human CD83 (RA83) depletes activated DC and suppresses alloimmune reactions in vitro, we tested the effect of RA83 treatment on T cell immunity in vitro and its ability to prevent human PBMC induced xenogeneic AGVHD in vivo. The effect of RA83 treatment on T cell numbers, proliferation and cytokine secretion in allogeneic MLR was compared with appropriate controls, including Campath-1H. Allogeneic responses in vitro were mirrored in a DC dependent in vivo model of xenogeneic AGVHD, in which 50×106 human PBMC were injected into an irradiated SCID mouse. Human cytokine levels were measured in MLR tissue culture supernatant (TCSN) and mouse serum at the time of sacrifice. Cytotoxic T cell responses to viral antigens (CMV and FMP) were analysed by specific pentamer analysis and Cr51 release assays, prior to and following HLA restricted peptide antigen specific expansion. RA83 was shown to have NK-mediated ADCC capacity. Cellular proliferation in the allogeneic MLR was reduced by both RA83 and Campath-1H treatment (p= 0.004 and 0.01 respectively vs controls) and both antibodies improved mouse survival in the human xenogenic AGVHD model (RA83: 93%, Campath-1H: 100%, p<0.0001). IFN-g was significantly reduced in the TCSN from MLR treated with RA83 (p=0.0391) and in sera taken from RA83 (p=0.0002) and Campath-1H (p=0.0051) treated mice. Serum IL-4 levels were maintained in RA83 and Campath-1H treated mice. The serum levels of IL-5, IL-8 and TNF in mice treated with RA83 were markedly reduced compared to controls (p=0.0256, 0.0025, 0.025, respectively), and the reductions were similar to those seen in Campath-1H treated mice. Similar numbers of T cells were recovered from RA83 treated and control MLR, and both CMV and FMP specific CD8+ T cells were retained. These cells were readily expanded by peptide pulsing and autologous restimulation and had specific cytotoxic activity comparable to control cultures (see figure). In contrast, Campath-1H treatment removed specific anti-viral responses (vs controls: CMV: p<0.00001 and FMP: p=0.0051). Specific antibody to CD83 depletes activated DC in vitro and prevents xenogeneic human DC dependent AGVHD in vivo. This was accompanied by a Th1 to Th2 skewing of the cytokine response. RA83, but not Campath-1H treatment retained normal numbers of T cells and maintained normal cytotoxic responses to common post-transplant viral infections. Depletion of activated DC may be an effective means of AGVHD control, which maintains T cell immunity to life threatening infections and potentially anti-leukaemia responses. RA83 treatment of allo-MLR preserves T cell anti-CMV immunity RA83 treatment of allo-MLR preserves T cell anti-CMV immunity

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