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1.
BMJ Case Rep ; 16(8)2023 Aug 18.
Article in English | MEDLINE | ID: mdl-37597857

ABSTRACT

Histoplasmosis is an endemic fungal infection caused by the dimorphic fungus, Histoplasma capsulatum, which is treated with intravenous amphotericin B and oral itraconazole as first-line and second-line therapy. We report a case of a man in his early 70s treated with methotrexate and infliximab for rheumatoid arthritis who developed disseminated histoplasmosis. The patient was unable to absorb itraconazole due to intractable diarrhoea and developed a severe, anaphylactoid reaction or an immune reconstitution inflammatory syndrome when treated with liposomal amphotericin B. He was subsequently treated with isavuconazole and steroids and made a full recovery.A literature review revealed other cases of histoplasmosis which were treated with isavuconazole including both primary pulmonary and disseminated presentations. Cases of blastomycosis which were treated with isavuconazole are also reviewed including those with severe immunocompromised statuses including solid-organ transplant and tumour necrosis factor-alpha antagonist recipients. Our report describes the potential role of isavuconazole in cases of histoplasmosis where first-line and second-line therapies have failed or are contraindicated (excluding meningitis).


Subject(s)
Histoplasmosis , Male , Humans , Histoplasmosis/diagnosis , Histoplasmosis/drug therapy , Itraconazole , Triazoles/therapeutic use , Nitriles/therapeutic use
2.
Mol Ther ; 30(12): 3587-3600, 2022 12 07.
Article in English | MEDLINE | ID: mdl-36299240

ABSTRACT

Zinc-finger nuclease (ZFN)-based in vivo genome editing is a novel treatment that can potentially provide lifelong protein replacement with single intravenous administration. Three first-in-human open-label ascending single-dose phase 1/2 studies were performed in parallel (starting November 2017) primarily to assess safety and tolerability of ZFN in vivo editing therapy in mucopolysaccharidosis I (MPS I) (n = 3), MPS II (n = 9), and hemophilia B (n = 1). Treatment was well tolerated with no serious treatment-related adverse events. At the 1e13 vg/kg dose, evidence of genome editing was detected through albumin-transgene fusion transcripts in liver for MPS II (n = 2) and MPS I (n = 1) subjects. The MPS I subject also had a transient increase in leukocyte iduronidase activity to the lower normal range. At the 5e13 vg/kg dose, one MPS II subject had a transient increase in plasma iduronate-2-sulfatase approaching normal levels and one MPS I subject approached mid-normal levels of leukocyte iduronidase activity with no evidence of genome editing. The hemophilia B subject was not able to decrease use of factor IX concentrate; genome editing could not be assessed. Overall, ZFN in vivo editing therapy had a favorable safety profile with evidence of targeted genome editing in liver, but no long-term enzyme expression in blood.


Subject(s)
Zinc Finger Nucleases , Humans
3.
J Org Chem ; 87(10): 6760-6768, 2022 05 20.
Article in English | MEDLINE | ID: mdl-35486501

ABSTRACT

Diarylamines possess two potentially atropisomeric C-N axes; however, there are few examples of atropisomerically stable diarylamines in the literature, as the contiguous axes can allow for low energy racemization pathways via concerted bond rotations. Herein, we describe highly atropisomerically stable diarylamines that possess barriers to racemization of 30-36 kcal/mol, corresponding to half-lives to racemization on the decade to century time scale at room temperature. Investigation of the factors that led to the high stereochemical stability suggests that increased conjugation of the aniline lone pair of electrons into a more electron-deficient aryl ring, coupled with intramolecular hydrogen-bonding, locked the corresponding axis into a defined planar conformation, disfavoring the lower energy racemization pathways.


Subject(s)
Electrons , Hydrogen Bonding , Molecular Conformation
4.
3 Biotech ; 10(11): 491, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33134009

ABSTRACT

In this study, a bacterial consortium ASDF was developed, capable of degrading fluoranthene (a non-alternant poly-aromatic hydrocarbon). It comprised of three bacterial strains: Pseudomonas sp. ASDF1, Burkholderia sp. ASDF2 and Mycobacterium sp. ASDF3 capable of degrading 100 mg/L of fluoranthene under experimentally defined and optimum conditions (37 °C, pH 7.0, 150 rpm) within 7 days. Consortium had metabolized fluoranthene as sole source of carbon and energy with maximum degradation rate of 0.52 mg/L/h and growth rate of 0.054/h. Fluoranthene degradation is an aerobic process, therefore with increasing the gyratory shaking from 50 to 150 rpm, degradation was concurrently enhanced by 7.1-fold. The synthetic surfactants SDS and CTAB had antagonistic effect on fluoranthene degradation (decreased up to 2.8-fold). The proficiency of consortium was assessed for its inherent ability to degrade seven other hydrocarbons both individually as well as in mixture. The degradation profile was studied using HPLC and the detection of two degraded intermediates (salicylic acid and derivatives of phthalic acid) suggested that fluoranthene degradation might have occurred via ortho- and meta-cleavage pathways. The competency of consortium was further validated through simulated microcosm studies, which showed 96% degradation of fluoranthene in soil ecosystem under the ambient conditions. Hence, the study suggested that the consortium ASDF has an inherent potential for its wide applicability in bioremediation of hydrocarbon-contaminated sites.

5.
J Org Chem ; 85(21): 13895-13905, 2020 11 06.
Article in English | MEDLINE | ID: mdl-33044067

ABSTRACT

We report a highly efficient ortho-selective electrophilic chlorination of phenols utilizing a Lewis basic selenoether catalyst. The selenoether catalyst resulted in comparable selectivities to our previously reported bis-thiourea ortho-selective catalyst, with a catalyst loading as low as 1%. The new catalytic system also allowed us to extend this chemistry to obtain excellent ortho-selectivities for unprotected anilines. The selectivities of this reaction are up to >20:1 ortho/para, while the innate selectivities for phenols and anilines are approximately 1:4 ortho/para. A series of preliminary studies revealed that the substrates require a hydrogen-bonding moiety for selectivity.

6.
J Am Chem Soc ; 142(5): 2198-2203, 2020 02 05.
Article in English | MEDLINE | ID: mdl-31944689

ABSTRACT

Diarylamines and related scaffolds are among the most common chemotypes in modern drug discovery. While they can potentially possess two chiral axes, there are no studies on their enantioselective synthesis, as these axes typically possess lower stereochemical stabilities. Herein, we report a chiral phosphoric acid catalyzed atroposelective electrophilic halogenation of N-aryl quinoids, a class of compounds that are analogous to diarylamines. This chemistry yields a large range of stereochemically stable N-aryl quinoids in excellent yields and atroposelectivity. This work represents the first example of the atroposelective synthesis of a diarylamine-like scaffold and will serve as a gateway to fundamental and applied studies on the scarcely studied chirality of these ubiquitous chiral scaffolds.


Subject(s)
Hydroquinones/chemical synthesis , Catalysis , Hydroquinones/chemistry , Stereoisomerism , Thermodynamics
7.
Front Microbiol ; 9: 1333, 2018.
Article in English | MEDLINE | ID: mdl-30013520

ABSTRACT

Chrysene is a high molecular weight (HMW), polycyclic aromatic hydrocarbon (PAH) known for its recalcitrance and carcinogenic properties and sparsely soluble (0.003 mg/L) in aqueous medium. Due to these refractory properties, bioavailability of chrysene is very low and therefore is persistence in the environment escaping the metabolism by microorganisms. However, few bacterial and fungal strains are reported to degrade chrysene, but with lower efficiency, requiring additional/extraneous carbon sources (co-substrates) for it's complete mineralization. In this study, development, enrichment and characterization of bacterial consortium ASDC, consisting of Rhodococcus sp., ASDC1; Bacillus sp. ASDC2; and Burkholderia sp. ASDC3 were reported. Chrysene was utilized as a sole source of carbon and energy by the consortium, having maximum degradation rate of 1.5 mg/L/day and maximum growth rate of 0.125/h, under optimized conditions of pH 7.0, 37°C under aeration of 150 rpm on gyrating shaking. Chrysene degradation was unaffected in presence of other PAHs like pyrene, fluoranthene, naphthalene, phenanthrene, benzene, toluene and xylene, individually as well as in mixture. The results revealed that peptone, ammonium nitrate, sodium succinate have enhanced the chrysene degradation rate during first 24 h of experimentation, which was later on inhibited with increase in incubation time. The chrysene degradation was inhibited by mercury even at lower concentration (1 mM). The results also revealed that SDS has enhanced its degradation by 5.2-fold for initial 24 h of growth, but with increasing in the incubation period, it decreases by 1.2-fold on 7th day of experimentation. The HPLC studies suggested that chrysene was degraded through phthalic acid pathway by the consortium ASDC and the stoichiometric measurements indicated the complete mineralization of chrysene. The flask scale results were validated at simulated microcosm models, where enriched consortium ASDC exhibited maximum degradation (96%) in polluted, non-sterile soil sediment, indicating that consortial strains along with indigenous metabolism showed synergistic metabolism for degradation of chrysene. Thus, the above study revealed the useful enrichment of bacterial community for synergistic degradation of PAHs (chrysene) which could be further exploited for in situ remediation of PAH contaminated sites.

8.
3 Biotech ; 7(1): 29, 2017 May.
Article in English | MEDLINE | ID: mdl-28401465

ABSTRACT

Polycyclic aromatic hydrocarbons (PAHs) are highly recalcitrant compounds due to their high hydrophobicity and tendency to partition in organic phase of soils. Pyrene is a high-molecular weight PAH, which has human health concerns. In the present study, a bacterial consortium, PBR, was developed from a long-term polluted site, viz., Amlakhadi, Ankleshwar, Gujarat, for effective degradation of pyrene. The consortium effectively metabolized pyrene as a sole source of carbon and energy. The consortium comprised three bacterial species, Pseudomonas sp. ASDP1, Burkholderia sp. ASDP2, and Rhodococcus sp. ASDP3. The maximum growth rate of consortium was 0.060/h and the maximum pyrene degradation rate was 16 mg/l/day. The organic and inorganic nutrients along with different surfactants did not affect pyrene degradation, but degradation rate moderately increased in the presence of sodium succinate. The significant characteristic of the consortium was that it possessed an ability to degrade six other hydrocarbons, both independently and simultaneously at 37 °C, in BHM (pH 7.0) under shaking conditions (150 rpm) and it showed resistance towards mercury at 10 mM concentration. Phthalic acid as one of the intermediates during pyrene degradation was detected through high-performance liquid chromatography (HPLC). The efficiency of consortium for pyrene degradation was validated in simulated microcosms' study, which indicated that 99% of pyrene was metabolized by the consortium under ambient conditions.

9.
Org Lett ; 17(24): 6218-21, 2015 Dec 18.
Article in English | MEDLINE | ID: mdl-26650567

ABSTRACT

A biogenetic type total synthesis of alkaloids phaitanthrin D and phaitanthrin E has been described. The Csp(3)-Csp(3) bond cleavage with the release of several heteroatoms bearing unexpected leaving groups in intramolecular substitution reactions on an iminium double bond in the quinazolinones has been demonstrated using HMDS/ZnCl2 or NaHMDS. The mechanistic aspects have been supported by isolation and characterization of appropriate intermediates.


Subject(s)
Quinazolinones/chemistry , Quinazolinones/chemical synthesis , Alkaloids/chemistry , Biomimetics , Molecular Structure , Orchidaceae/chemistry , Stereoisomerism
10.
Eur J Immunol ; 44(10): 2938-48, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25043727

ABSTRACT

The acquisition and maintenance of NK-cell function is mediated by inhibitory killer-cell immunoglobulin-like receptors (KIRs) through their interaction with HLA class I molecules. Recently, HLA-C expression levels were shown to be correlated with protection against multiple outcomes of HIV-1 infection; however, the underlying mechanisms are poorly understood. As HLA-C is the natural ligand for the inhibitory receptors KIR2DL1 and KIR2DL2/3, we sought to determine whether HLA-C group haplotypes affect NK-cell responses during primary HIV-1 infection. The phenotypes and functional capacity of NK cells derived from HIV-1-positive and HIV-1-negative individuals were assessed (N = 42 and N = 40, respectively). HIV-1 infection was associated with an increased frequency of KIR2DL1-3(+) NK cells. Further analysis showed that KIR2DL1(+) NK cells were selectively increased in individuals homozygous for HLA-C2, while HLA-C1-homozygous individuals displayed increased proportions of KIR2DL2/3(+) NK cells. KIR2DL1-3(+) NK cells were furthermore more polyfunctional during primary HIV-1 infection in individuals also encoding for their cognate HLA-C group haplotypes, as measured by degranulation and IFN-γ and TNF-α production. These results identify a novel relationship between HLA-C and KIR2DL(+) NK-cell subsets and demonstrate that HLA-C-mediated licensing modulates NK-cell responses to primary HIV-1 infection.


Subject(s)
HIV Infections/genetics , HIV Infections/immunology , HLA-C Antigens/immunology , Killer Cells, Natural/immunology , Lymphocyte Subsets/immunology , Adult , Female , Flow Cytometry , HLA-C Antigens/genetics , Haplotypes , Humans , Male , Middle Aged , Receptors, KIR2DL1/immunology , Receptors, KIR2DL2/immunology , Receptors, KIR2DL3/immunology
11.
J Infect Dis ; 210(7): 1042-6, 2014 Oct 01.
Article in English | MEDLINE | ID: mdl-24688071

ABSTRACT

Inflammation in early human immunodeficiency virus type 1 (HIV-1) disease progression is not well characterized. Ninety patients with untreated primary HIV-1 infection were studied to determine associations of inflammatory proteins with early disease progression. High plasma tumor necrosis factor α (TNF-α) levels (≥8.5 pg/mL) were significantly associated with an increased viral load set point and shorter times to reaching a CD4(+) T-cell count of <500 cells/mm(3) and initiating antiretroviral therapy. The increased risk of reaching a CD4(+) T-cell count of <500 cells/mm(3) in the group with high TNF-α levels was driven by viral load but was independent of concurrent CD4(+) T-cell count. Thus, TNF-α appears to be an important mediator of inflammation in patients with poor viral control and early HIV-1 disease progression.


Subject(s)
HIV Infections/immunology , HIV-1/immunology , Tumor Necrosis Factor-alpha/blood , Adult , CD4 Lymphocyte Count , Cohort Studies , Female , HIV Infections/virology , Humans , Male , Viral Load
12.
Retrovirology ; 10: 139, 2013 Nov 18.
Article in English | MEDLINE | ID: mdl-24245727

ABSTRACT

BACKGROUND: HLA-B alleles are associated with viral control in chronic HIV-1 infection, however, their role in primary HIV-1 disease is unclear. This study sought to determine the role of HLA-B alleles in viral control during the acute phase of HIV-1 infection and establishment of the early viral load set point (VLSP). FINDINGS: Individuals identified during primary HIV-1 infection were HLA class I typed and followed longitudinally. Associations between HLA-B alleles and HIV-1 viral replication during acute infection and VLSP were analyzed in untreated subjects. The results showed that neither HLA-B*57 nor HLA-B*27 were significantly associated with viral control during acute HIV-1 infection (Fiebig stage I-IV, n=171). HLA-B*57 was however significantly associated with a subsequent lower VLSP (p<0.001, n=135) with nearly 1 log10 less median viral load. Analysis of a known polymorphism at position 97 of HLA-B showed significant associations with both lower initial viral load (p<0.01) and lower VLSP (p<0.05). However, this association was dependent on different amino acids at this position for each endpoint. CONCLUSIONS: The effect of HLA-B*57 on viral control is more pronounced during the later stages of primary HIV-1 infection, which suggests the underlying mechanism of control occurs at a critical period in the first several months after HIV-1 acquisition. The risk profile of polymorphisms at position 97 of HLA-B are more broadly associated with HIV-1 viral load during primary infection and may serve as a focal point in further studies of HLA-B function.


Subject(s)
HIV Infections/immunology , HIV Infections/virology , HIV-1/immunology , HLA-B Antigens/immunology , Adult , Amino Acid Substitution , Female , HLA-B Antigens/genetics , Humans , Longitudinal Studies , Male , Middle Aged , Point Mutation , Polymorphism, Genetic , Time Factors , Viral Load
13.
Org Lett ; 15(15): 4006-9, 2013 Aug 02.
Article in English | MEDLINE | ID: mdl-23862684

ABSTRACT

Insertion reactions of an in situ generated arynes to a variety of suitably substituted 1,3-quinazolin-4-ones have been demonstrated for a new efficient one-step approach to a diverse range of fused quinazolinone architectures. The present protocol has been effectively utilized to accomplish the concise total synthesis of recently isolated bioactive natural products tryptanthrin, phaitanthrins A-C, and cruciferane.


Subject(s)
Biological Products/chemistry , Quinazolines/chemistry , Quinazolinones/chemical synthesis , Molecular Structure , Quinazolinones/chemistry , Stereoisomerism
14.
BMC Public Health ; 10: 278, 2010 May 26.
Article in English | MEDLINE | ID: mdl-20500896

ABSTRACT

BACKGROUND: In the United States, the risk of rabies transmission to humans in most situations of possible exposure is unknown. Controlled studies on rabies are clearly not possible. Thus, the limited data on risk has led to the frequent administration of rabies post-exposure prophylaxis (PEP), often in inappropriate circumstances. METHODS: We used the Delphi method to obtain an expert group consensus estimate of the risk of rabies transmission to humans in seven scenarios of potential rabies exposure. We also surveyed and discussed the merits of recommending rabies PEP for each scenario. RESULTS: The median risk of rabies transmission without rabies PEP for a bite exposure by a skunk, bat, cat, and dog was estimated to be 0.05, 0.001, 0.001, and 0.00001, respectively. Rabies PEP was unanimously recommended in these scenarios. However, rabies PEP was overwhelmingly not recommended for non-bite exposures (e.g. dog licking hand but unavailable for subsequent testing), estimated to have less than 1 in 1,000,000 (0.000001) risk of transmission. CONCLUSIONS: Our results suggest that there are many common situations in which the risk of rabies transmission is so low that rabies PEP should not be recommended. These risk estimates also provide a key parameter for cost-effective models of human rabies prevention and can be used to educate health professionals about situation-specific administration of rabies PEP.


Subject(s)
Bites and Stings , Post-Exposure Prophylaxis , Rabies/epidemiology , Rabies/transmission , Animals , Cats , Chiroptera , Delphi Technique , Dogs , Humans , Mephitidae , Rabies Vaccines/administration & dosage , Risk , Saliva/virology , United States/epidemiology
15.
Vaccine ; 26(33): 4251-5, 2008 Aug 05.
Article in English | MEDLINE | ID: mdl-18599167

ABSTRACT

There is growing concern in the United States about the excessive use of rabies post exposure prophylaxis (PEP) treatment. In this paper we have estimated the cost effectiveness of rabies PEP treatment under various scenarios of rabies transmission. When the risk of a patient getting rabies is deemed greater than 0.7%, then giving PEP will be cost saving (societal perspective). For lower risks of transmission, cost effectiveness estimates ranged from approximately $500,000 per life saved to $billions. The uncertainty caused by the wide range of cost effectiveness can only be resolved through analysis of data describing rabies transmission risk in a variety of scenarios.


Subject(s)
Rabies Vaccines/economics , Rabies Vaccines/immunology , Rabies/prevention & control , Cost-Benefit Analysis , Humans , Models, Theoretical , United States
16.
MMWR Recomm Rep ; 57(RR-3): 1-28, 2008 May 23.
Article in English | MEDLINE | ID: mdl-18496505

ABSTRACT

These recommendations of the Advisory Committee on Immunization Practices (ACIP) update the previous recommendations on human rabies prevention (CDC. Human rabies prevention--United States, 1999: recommendations of the Advisory Committee on Immunization Practices. MMWR 1999;48 [No. RR-1]) and reflect the status of rabies and antirabies biologics in the United States. This statement 1) provides updated information on human and animal rabies epidemiology; 2) summarizes the evidence regarding the effectiveness/efficacy, immunogenicity, and safety of rabies biologics; 3) presents new information on the cost-effectiveness of rabies postexposure prophylaxis; 4) presents recommendations for rabies postexposure and pre-exposure prophylaxis; and 5) presents information regarding treatment considerations for human rabies patients. These recommendations involve no substantial changes to the recommended approach for rabies postexposure or pre-exposure prophylaxis. ACIP recommends that prophylaxis for the prevention of rabies in humans exposed to rabies virus should include prompt and thorough wound cleansing followed by passive rabies immunization with human rabies immune globulin (HRIG) and vaccination with a cell culture rabies vaccine. For persons who have never been vaccinated against rabies, postexposure antirabies vaccination should always include administration of both passive antibody (HRIG) and vaccine (human diploid cell vaccine [HDCV] or purified chick embryo cell vaccine [PCECV]). Persons who have ever previously received complete vaccination regimens (pre-exposure or postexposure) with a cell culture vaccine or persons who have been vaccinated with other types of vaccines and have previously had a documented rabies virus neutralizing antibody titer should receive only 2 doses of vaccine: one on day 0 (as soon as the exposure is recognized and administration of vaccine can be arranged) and the second on day 3. HRIG is administered only once (i.e., at the beginning of antirabies prophylaxis) to previously unvaccinated persons to provide immediate, passive, rabies virus neutralizing antibody coverage until the patient responds to HDCV or PCECV by actively producing antibodies. A regimen of 5 1-mL doses of HDCV or PCECV should be administered intramuscularly to previously unvaccinated persons. The first dose of the 5-dose course should be administered as soon as possible after exposure (day 0). Additional doses should then be administered on days 3, 7, 14, and 28 after the first vaccination. Rabies pre-exposure vaccination should include three 1.0-mL injections of HDCV or PCECV administered intramuscularly (one injection per day on days 0, 7, and 21 or 28). Modifications were made to the language of the guidelines to clarify the recommendations and better specify the situations in which rabies post- and pre-exposure prophylaxis should be administered. No new rabies biologics are presented, and no changes were made to the vaccination schedules. However, rabies vaccine adsorbed (RVA, Bioport Corporation) is no longer available for rabies postexposure or pre-exposure prophylaxis, and intradermal pre-exposure prophylaxis is no longer recommended because it is not available in the United States.


Subject(s)
Immunoglobulins, Intravenous/therapeutic use , Immunologic Factors/therapeutic use , Rabies Vaccines , Rabies/prevention & control , Animals , Contraindications , Humans , Immunoglobulins, Intravenous/adverse effects , Immunologic Factors/adverse effects , Rabies/epidemiology , Rabies/therapy , Rabies/veterinary , Rabies Vaccines/administration & dosage , Rabies Vaccines/adverse effects , Rabies virus/immunology , Serologic Tests , United States/epidemiology , Vaccination
17.
Anaerobe ; 12(2): 63-6, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16701615

ABSTRACT

The in vitro activity of 11 antimicrobials was tested against 74 recent anaerobic isolates obtained from pretreatment cultures in pediatric patients with complicated intra-abdominal infections using the CLSI M11-A-6 agar dilution method. Carbapenems, beta-lactamase inhibitor combinations and metronidazole retained good activity, while all Bacteroides fragilis group species produced beta-lactamase and were penicillin resistant and 43% were either intermediately susceptible or resistant to clindamycin. Cefoxitin had moderate activity against B. fragilis but poor activity against Bacteroides thetaiotaomicron and other B. fragilis group isolates.


Subject(s)
Anti-Bacterial Agents/pharmacology , Bacteria, Anaerobic/drug effects , Bacterial Infections/drug therapy , Microbial Sensitivity Tests , Bacteria, Anaerobic/classification , Bacteria, Anaerobic/isolation & purification , Bacterial Infections/microbiology , Child , Drug Resistance, Bacterial , Humans , Peritonitis/drug therapy , Peritonitis/microbiology
18.
J Clin Microbiol ; 44(3): 1184-6, 2006 Mar.
Article in English | MEDLINE | ID: mdl-16517927

ABSTRACT

Ochrobactrum intermedium [corrected] infection is rare in humans and is generally associated with immunocompromised hosts with indwelling foreign bodies. We report a case of pelvic abscess with O. intermedium [corrected] after a routine appendectomy in an immunocompetent patient and review the literature on O. intermedium [corrected] infection in patients with normal immune function.


Subject(s)
Abscess/microbiology , Gram-Negative Bacterial Infections/microbiology , Ochrobactrum anthropi/pathogenicity , Pelvic Infection/microbiology , Abscess/immunology , Appendectomy/adverse effects , Gram-Negative Bacterial Infections/immunology , Humans , Immunocompetence , Male , Middle Aged , Pelvic Infection/immunology , Postoperative Complications/immunology , Postoperative Complications/microbiology
19.
J Immunol ; 174(3): 1602-7, 2005 Feb 01.
Article in English | MEDLINE | ID: mdl-15661922

ABSTRACT

Type I IFNs are well established antiviral cytokines that have also been shown to be induced by bacteria. However, the signaling mechanisms regulating the activation of these cytokines during bacterial infections remain poorly defined. We show that although Gram-negative bacteria can activate the type I IFN pathway through TLR4, the intracellular Gram-positive bacterium Listeria monocytogenes (LM) can do so independently of TLR4 and TLR2. Furthermore, experiments using genetic mutants and chemical inhibitors suggest that LM-induced type I IFN activation occurs by an intracellular pathway involving the serine-threonine kinase TNFR-associated NF-kappaB kinase (TANK)-binding kinase 1 (TBK1). Interestingly, receptor-interacting protein 2, a component of the recently discovered nucleotide-binding oligomerization domain-dependent intracellular detection pathway, was not involved. Taken together, our data describe a novel signal transduction pathway involving TBK1 that is used by LM to activate type I IFNs. Additionally, we provide evidence that both the LM- and TLR-dependent pathways converge at TBK1 to activate type I IFNs, highlighting the central role of this molecule in modulating type I IFNs in host defense and disease.


Subject(s)
Interferon Type I/biosynthesis , Listeria monocytogenes/immunology , Lymphocyte Activation/immunology , Protein Serine-Threonine Kinases/physiology , Receptors, Cell Surface/physiology , Signal Transduction/immunology , Animals , Bone Marrow Cells/enzymology , Bone Marrow Cells/immunology , Bone Marrow Cells/microbiology , Cells, Cultured , Cytosol/enzymology , Cytosol/immunology , Cytosol/microbiology , Interferon Type I/deficiency , Interferon Type I/genetics , Interferon Type I/physiology , Macrophages/enzymology , Macrophages/immunology , Macrophages/microbiology , Mice , Mice, Inbred C57BL , Mice, Knockout , Protein Serine-Threonine Kinases/deficiency , Protein Serine-Threonine Kinases/genetics , Receptor-Interacting Protein Serine-Threonine Kinase 2 , Receptor-Interacting Protein Serine-Threonine Kinases , Receptors, Cell Surface/deficiency , Receptors, Cell Surface/genetics , Signal Transduction/genetics , Toll-Like Receptor 2 , Toll-Like Receptor 4
20.
J Exp Med ; 200(4): 437-45, 2004 Aug 16.
Article in English | MEDLINE | ID: mdl-15302901

ABSTRACT

Numerous bacterial products such as lipopolysaccharide potently induce type I interferons (IFNs); however, the contribution of this innate response to host defense against bacterial infection remains unclear. Although mice deficient in either IFN regulatory factor (IRF)3 or the type I IFN receptor (IFNAR)1 are highly susceptible to viral infection, we show that these mice exhibit a profound resistance to infection caused by the Gram-positive intracellular bacterium Listeria monocytogenes compared with wild-type controls. Furthermore, this enhanced bacterial clearance is accompanied by a block in L. monocytogenes-induced splenic apoptosis in IRF3- and IFNAR1-deficient mice. Thus, our results highlight the disparate roles of type I IFNs during bacterial versus viral infections and stress the importance of proper IFN modulation in host defense.


Subject(s)
Apoptosis/immunology , DNA-Binding Proteins/deficiency , Interferon Type I/immunology , Listeriosis/immunology , Receptors, Interferon/deficiency , Transcription Factors/deficiency , Animals , DNA Primers , Disease Susceptibility , Enzyme-Linked Immunosorbent Assay , Immunoblotting , In Situ Nick-End Labeling , Interferon Regulatory Factor-3 , Liver/pathology , Macrophages/immunology , Membrane Proteins , Mice , Mice, Inbred C57BL , Polymerase Chain Reaction/methods , Receptor, Interferon alpha-beta , Spleen/immunology
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