RESUMO
The combination of copper-metal organic framework (Cu-MOF) with graphene oxide (GO) has received growing interest in electrocatalysis, energy storage and sensing applications. However, its potential as an electrochemical biosensing platform remains largely unexplored. In this study, we introduce the synthesis of GO/Cu-MOF nanocomposite and its application in the simultaneous detection of two biomarkers associated with lower respiratory infections, marking the first instance of its use in this capacity. The physicochemical properties and structural elucidation of this composite were studied with the support of XRD, FTIR, SEM and electrochemical techniques. The immunosensor was fabricated by drop casting the nanocomposite on dual screen-printed electrodes followed by functionalization with pyrene linker. The covalent immobilization of the monoclonal antibodies of the bacterial antigens of Mycoplasma pneumoniae (M. pneumoniae; M. p.) and Legionella pneumophila (L. pneumophila; L. p.) was achieved using EDC-NHS chemistry. The differential pulse voltammetry (DPV) signals of the developed immunosensor platform demonstrated a robust correlation across a broad concentration range from 1 pg/mL to 100 ng/mL. The immunosensor platform has shown high degree of selectivity against antigens for various respiratory pathogens. Moreover, the dual immunosensor was successfully applied for the detection of M. pneumoniae and L. pneumophila antigens in spiked water samples showing excellent recovery percentages. We attribute the high sensitivity of the immunosensor to the enhanced electrocatalytic characteristics, stability and conductivity of the GO-MOF composite as well as the synergistic interactions between the GO and MOF. This immunosensor offers a swift analytical response, simplicity in fabrication and instrumentation, rendering it an appealing platform for the on-field monitoring of pathogens in environmental samples.
Assuntos
Antígenos de Bactérias , Técnicas Biossensoriais , Cobre , Técnicas Eletroquímicas , Grafite , Legionella pneumophila , Estruturas Metalorgânicas , Mycoplasma pneumoniae , Legionella pneumophila/imunologia , Legionella pneumophila/isolamento & purificação , Mycoplasma pneumoniae/imunologia , Mycoplasma pneumoniae/isolamento & purificação , Grafite/química , Técnicas Eletroquímicas/métodos , Técnicas Biossensoriais/métodos , Cobre/química , Estruturas Metalorgânicas/química , Antígenos de Bactérias/imunologia , Antígenos de Bactérias/análise , Imunoensaio/métodos , Microbiologia da Água , Nanocompostos/químicaRESUMO
Through immune memory, infections have a lasting effect on the host. While memory cells enable accelerated and enhanced responses upon rechallenge with the same pathogen, their impact on susceptibility to unrelated diseases is unclear. We identify a subset of memory T helper 1 (Th1) cells termed innate acting memory T (TIA) cells that originate from a viral infection and produce IFN-γ with innate kinetics upon heterologous challenge in vivo. Activation of memory TIA cells is induced in response to IL-12 in combination with IL-18 or IL-33 but is TCR independent. Rapid IFN-γ production by memory TIA cells is protective in subsequent heterologous challenge with the bacterial pathogen Legionella pneumophila. In contrast, antigen-independent reactivation of CD4+ memory TIA cells accelerates disease onset in an autoimmune model of multiple sclerosis. Our findings demonstrate that memory Th1 cells can acquire additional TCR-independent functionality to mount rapid, innate-like responses that modulate susceptibility to heterologous challenges.
Assuntos
Imunidade Inata , Memória Imunológica , Interferon gama , Células Th1 , Células Th1/imunologia , Animais , Memória Imunológica/imunologia , Camundongos , Interferon gama/metabolismo , Interferon gama/imunologia , Células T de Memória/imunologia , Camundongos Endogâmicos C57BL , Legionella pneumophila/imunologia , Esclerose Múltipla/imunologia , Interleucina-12/metabolismo , Interleucina-12/imunologiaRESUMO
Legionella species are Gram-negative intracellular bacteria that evolved in soil and freshwater environments, where they infect and replicate within various unicellular protozoa. The primary virulence factor of Legionella is the expression of a type IV secretion system (T4SS), which contributes to the translocation of effector proteins that subvert biological processes of the host cells. Because of its evolution in unicellular organisms, T4SS effector proteins are not adapted to subvert specific mammalian signaling pathways and immunity. Consequently, Legionella pneumophila has emerged as an interesting infection model for investigating immune responses against pathogenic bacteria in multicellular organisms. This review highlights recent advances in our understanding of mammalian innate immunity derived from studies involving L. pneumophila. This includes recent insights into inflammasome-mediated mechanisms restricting bacterial replication in macrophages, mechanisms inducing cell death in response to infection, induction of effector-triggered immunity, activation of specific pulmonary cell types in mammalian lungs, and the protective role of recruiting monocyte-derived cells to infected lungs.
Assuntos
Imunidade Inata , Legionella pneumophila , Doença dos Legionários , Legionella pneumophila/imunologia , Legionella pneumophila/patogenicidade , Humanos , Animais , Doença dos Legionários/imunologia , Doença dos Legionários/microbiologia , Fagócitos/imunologia , Fagócitos/microbiologia , Sistemas de Secreção Tipo IV/imunologia , Sistemas de Secreção Tipo IV/genética , Sistemas de Secreção Tipo IV/metabolismo , Inflamassomos/imunologia , Inflamassomos/metabolismo , Monócitos/imunologia , Monócitos/microbiologia , Fatores de Virulência/imunologia , Fatores de Virulência/metabolismo , Macrófagos/imunologia , Macrófagos/microbiologia , Interações Hospedeiro-Patógeno/imunologiaRESUMO
Many emerging and re-emerging infectious diseases are prevalent, and the number of patients with allergies is increasing. Therefore, the importance of purifying the living environment is increasing. Photocatalysts undergo extreme redox reactions and decompose organic matter upon exposure to the excitation light. In contrast to ultraviolet light and disinfectants, which are standard methods for inactivating viruses and eliminating microorganisms, photocatalysts can decompose toxic substances, such as endotoxins and allergens, rendering them harmless to the human body. Photocatalysts have attracted significant attention as potential antiviral and antimicrobial agents. This review outlines the antiviral, antimicrobial, and anti-allergenic effects of photocatalysts. Especially, we have discussed the inactivation of SARS-CoV-2 in liquids and aerosols, elimination of Legionella pneumophila in liquids, decomposition of its endotoxin, decomposition of cat and dog allergens, and elimination of their allergenicity using photocatalysts. Furthermore, we discuss future perspectives on how photocatalysts can purify living environments, and how photocatalytic technology can be applied to companion animals and the livestock industry.
Assuntos
Alérgenos , Alérgenos/imunologia , Alérgenos/química , Animais , Humanos , SARS-CoV-2/imunologia , SARS-CoV-2/efeitos da radiação , Catálise/efeitos da radiação , Desinfecção/métodos , Processos Fotoquímicos , Legionella pneumophila/imunologia , Legionella pneumophila/efeitos da radiaçãoRESUMO
BACKGROUND: Patients with diabetes are particularly susceptible to Legionella pneumophila (LP) infection, but the exact pathogenesis of LP infection in diabetic patients is still not fully understood. Herein, we investigated the effect of diabetes on immune function during LP infection in vitro and in vivo. METHODS: The time course of LP infection in macrophages under normal and high-glucose (HG) conditions was examined in vitro. Western blot was used to determine nucleotide-binding oligomerization domain 1 (NOD1), kinase 1/2 (ERK1/2), mitogen-activated protein kinase p38 (MAPK p38), and c-Jun N-terminal kinases (JNK). Enzyme-linked immunosorbent assay (ELISA) was used to assess the secretion of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Cell Counting Kit-8 (CCK8) assay assessed U937 cell viability after treating cells with different concentrations of high sugar medium and ML130 (NOD1 inhibitor). For the in vivo study, normal and streptozocin-induced diabetic guinea pigs were infected with LP for 6, 24, and 72 h, after which NOD1, MAPK-related signals, TNF-α, and IL-6 expression in lung tissues were assessed using immunohistochemistry, western blot, and RT-PCR. RESULTS: HG attenuated the upregulation of NOD1 expression and reduced TNF-α and IL-6 secretion caused by LP compared with LP-infected cells exposed to normal glucose levels (all p < 0.05). In diabetic guinea pigs, HG inhibited the upregulation of NOD1 expression in lung tissues and the activation of p38, ERK1/2, and cJNK caused by LP infection compared to control pigs (all p < 0.05). CONCLUSION: HG attenuates the response of macrophages to LP infection by inhibiting NOD1 upregulation and the activation of MAPK signaling.
Assuntos
Glucose , Legionella pneumophila , Macrófagos , Proteína Adaptadora de Sinalização NOD1 , Proteína Adaptadora de Sinalização NOD1/metabolismo , Proteína Adaptadora de Sinalização NOD1/genética , Animais , Humanos , Macrófagos/imunologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Legionella pneumophila/imunologia , Glucose/metabolismo , Cobaias , Masculino , Interleucina-6/metabolismo , Doença dos Legionários/imunologia , Diabetes Mellitus Experimental/imunologia , Diabetes Mellitus Experimental/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Células U937 , Fator de Necrose Tumoral alfa/metabolismo , CamundongosRESUMO
Legionella pneumophila is an intracellular pathogen that can cause severe pneumonia after the inhalation of contaminated aerosols and replication in alveolar macrophages. Several pattern recognition receptors (PRRs) have been identified that contribute to the recognition of L. pneumophila by the innate immune system. However, the function of the C-type lectin receptors (CLRs), which are mainly expressed by macrophages and other myeloid cells, remains largely unexplored. Here, we used a library of CLR-Fc fusion proteins to search for CLRs that can bind the bacterium and identified the specific binding of CLEC12A to L. pneumophila. Subsequent infection experiments in human and murine macrophages, however, did not provide evidence for a substantial role of CLEC12A in controlling innate immune responses to the bacterium. Consistently, antibacterial and inflammatory responses to Legionella lung infection were not significantly influenced by CLEC12A deficiency. Collectively, CLEC12A is able to bind to L. pneumophila-derived ligands but does not appear to play a major role in the innate defense against L. pneumophila.
Assuntos
Interações Hospedeiro-Patógeno , Imunidade Inata , Lectinas Tipo C , Legionella pneumophila , Doença dos Legionários , Receptores Mitogênicos , Animais , Humanos , Camundongos , Lectinas Tipo C/metabolismo , Legionella pneumophila/imunologia , Doença dos Legionários/imunologia , Doença dos Legionários/microbiologia , Macrófagos/metabolismo , Macrófagos Alveolares/metabolismo , Receptores Mitogênicos/imunologiaRESUMO
Flagellin-induced NAIP/NLRC4 inflammasome activation and pyroptosis are critical events restricting Legionella pneumophila infection. However, the cellular and molecular dynamics of the in vivo responses against this bacterium are still unclear. We have found temporal coordination of two independent innate immunity pathways in controlling Legionella infection, the inflammasome activation and the CCR2-mediated Mo-DC recruitment. Inflammasome activation was an important player at the early stage of infection by lowering the numbers of bacteria for an efficient bacterial clearance conferred by the Mo-DC at the late stage of the infection. Mo-DC emergence highly depended on CCR2-signaling and dispensed inflammasome activation and pyroptosis. Also, Mo-DC compartment did not rely on the inflammasome machinery to deliver proper immune responses and was the most abundant cytokine-producing among the monocyte-derived cells in the infected lung. Importantly, when the CCR2- and NLRC4-dependent axes of response were simultaneously ablated, we observed an aggravated bacterial burden in the lung of infected mice. Taken together, we showed that inflammasome activation and CCR2-mediated immune response interplay in distinct pathways to restrict pulmonary bacterial infection. These findings extend our understanding of the in vivo integration and cooperation of different innate immunity arms in controlling infectious agents.
Assuntos
Células Dendríticas , Inflamassomos , Legionella pneumophila , Doença dos Legionários , Monócitos , Animais , Camundongos , Proteínas Reguladoras de Apoptose/metabolismo , Proteínas de Ligação ao Cálcio/metabolismo , Quimiotaxia de Leucócito/genética , Quimiotaxia de Leucócito/imunologia , Células Dendríticas/metabolismo , Inflamassomos/genética , Inflamassomos/metabolismo , Legionella pneumophila/imunologia , Doença dos Legionários/genética , Doença dos Legionários/imunologia , Macrófagos , Camundongos Knockout , Monócitos/metabolismo , Receptores CCR2/metabolismoRESUMO
Legionella pneumophila is found in the natural aquatic environment and can resist a wide range of environmental conditions. There are around fifty species of Legionella, at least twenty-four of which are directly linked to infections in humans. L. pneumophila is the cause of Legionnaires' disease, a potentially lethal form of pneumonia. By blocking phagosome-lysosome fusion, L. pneumophila lives and proliferates inside macrophages. For this disease, there is presently no authorized multiepitope vaccine available. For the multi-epitope-based vaccine (MEBV), the best antigenic candidates were identified using immunoinformatics and subtractive proteomic techniques. Several immunoinformatics methods were utilized to predict B and T cell epitopes from vaccine candidate proteins. To construct an in silico vaccine, epitopes (07 CTL, 03 HTL, and 07 LBL) were carefully selected and docked with MHC molecules (MHC-I and MHC-II) and human TLR4 molecules. To increase the immunological response, the vaccine was combined with a 50S ribosomal adjuvant. To maximize vaccine protein expression, MEBV was cloned and reverse-translated in Escherichia coli. To prove the MEBV's efficacy, more experimental validation is required. After its development, the resulting vaccine is greatly hoped to aid in the prevention of L. pneumophila infections.
Assuntos
Vacinas Bacterianas , Legionella pneumophila , Doença dos Legionários , Vacinas Bacterianas/genética , Vacinas Bacterianas/imunologia , Epitopos de Linfócito T/imunologia , Humanos , Legionella pneumophila/genética , Legionella pneumophila/imunologia , Doença dos Legionários/prevenção & controle , Proteômica , Receptor 4 Toll-Like/imunologiaRESUMO
Legionella pneumophila is the most common cause of the severe respiratory infection known as Legionnaires' disease. However, the microorganism is typically a symbiont of free-living amoeba, and our understanding of the bacterial factors that determine human pathogenicity is limited. Here we carried out a population genomic study of 902 L. pneumophila isolates from human clinical and environmental samples to examine their genetic diversity, global distribution and the basis for human pathogenicity. We find that the capacity for human disease is representative of the breadth of species diversity although some clones are more commonly associated with clinical infections. We identified a single gene (lag-1) to be most strongly associated with clinical isolates. lag-1, which encodes an O-acetyltransferase for lipopolysaccharide modification, has been distributed horizontally across all major phylogenetic clades of L. pneumophila by frequent recent recombination events. The gene confers resistance to complement-mediated killing in human serum by inhibiting deposition of classical pathway molecules on the bacterial surface. Furthermore, acquisition of lag-1 inhibits complement-dependent phagocytosis by human neutrophils, and promoted survival in a mouse model of pulmonary legionellosis. Thus, our results reveal L. pneumophila genetic traits linked to disease and provide a molecular basis for resistance to complement-mediated killing.
Assuntos
Proteínas do Sistema Complemento/imunologia , Legionella pneumophila/genética , Doença dos Legionários/imunologia , Doença dos Legionários/microbiologia , Acetiltransferases/genética , Acetiltransferases/imunologia , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Feminino , Genoma Bacteriano , Humanos , Legionella pneumophila/classificação , Legionella pneumophila/imunologia , Legionella pneumophila/isolamento & purificação , Camundongos , Camundongos Endogâmicos C57BL , Neutrófilos/imunologia , FilogeniaRESUMO
Cytokines made by macrophages play a critical role in determining the course of Legionella pneumophila infection. Prior murine-based modeling indicated that this cytokine response is initiated upon recognition of L. pneumophila by a subset of Toll-like receptors, namely TLR2, TLR5, and TLR9. Through the use of shRNA/siRNA knockdowns and subsequently CRISPR/Cas9 knockouts (KO), we determined that TRIF, an adaptor downstream of endosomal TLR3 and TLR4, is required for full cytokine secretion by human primary and cell-line macrophages. By characterizing a further set of TLR KO's in human U937 cells, we discerned that, contrary to the viewpoint garnered from murine-based studies, TLR3 and TLR4 (along with TLR2 and TLR5) are in fact vital to the macrophage response in the early stages of L. pneumophila infection. This conclusion was bolstered by showing that i) chemical inhibitors of TLR3 and TLR4 dampen the cytokine output of primary human macrophages and ii) transfection of TLR3 and TLR4 into HEK cells conferred an ability to sense L. pneumophila. TLR3- and TLR4-dependent cytokines promoted migration of human HL-60 neutrophils across an epithelial layer, pointing to the biological importance for the newfound signaling pathway. The response of U937 cells to L. pneumophila LPS was dependent upon TLR4, a further contradiction to murine-based studies, which had concluded that TLR2 is the receptor for Legionella LPS. Given the role of TLR3 in sensing nucleic acid (i.e., dsRNA), we utilized newly-made KO U937 cells to document that DNA-sensing by cGAS-STING and DNA-PK are also needed for the response of human macrophages to L. pneumophila. Given the lack of attention given them in the bacterial field, C-type lectin receptors were similarly examined; but, they were not required. Overall, this study arguably represents the most extensive, single-characterization of Legionella-recognition receptors within human macrophages.
Assuntos
Doença dos Legionários/imunologia , Macrófagos/imunologia , Moléculas com Motivos Associados a Patógenos/imunologia , Receptor 3 Toll-Like/imunologia , Receptor 4 Toll-Like/imunologia , Animais , Proteínas de Bactérias/imunologia , Humanos , Legionella pneumophila/imunologia , Lipopolissacarídeos/imunologia , Macrófagos/metabolismo , Camundongos , Moléculas com Motivos Associados a Patógenos/metabolismo , Receptor 3 Toll-Like/metabolismo , Receptor 4 Toll-Like/metabolismoRESUMO
The Dot/Icm type IV secretion system (T4SS) of Legionella pneumophila is essential for lysosomal evasion and permissiveness of macrophages for intracellular proliferation of the pathogen. In contrast, we show that polymorphonuclear cells (PMNs) respond to a functional Dot/Icm system through rapid restriction of L. pneumophila. Specifically, we show that the L. pneumophila T4SS-injected amylase (LamA) effector catalyzes rapid glycogen degradation in the PMNs cytosol, leading to cytosolic hyperglucose. Neutrophils respond through immunometabolic reprogramming that includes upregulated aerobic glycolysis. The PMNs become activated with spatial generation of intracellular reactive oxygen species within the Legionella-containing phagosome (LCP) and fusion of specific and azurophilic granules to the LCP, leading to rapid restriction of L. pneumophila. We conclude that in contrast to macrophages, PMNs respond to a functional Dot/Icm system, and specifically to the effect of the injected amylase effector, through rapid engagement of major microbicidal processes and rapid restriction of the pathogen. IMPORTANCE Legionella pneumophila is commonly found in aquatic environments and resides within a wide variety of amoebal hosts. Upon aerosol transmission to humans, L. pneumophila invades and replicates with alveolar macrophages, causing pneumonia designated Legionnaires' disease. In addition to alveolar macrophages, neutrophils infiltrate into the lungs of infected patients. Unlike alveolar macrophages, neutrophils restrict and kill L. pneumophila, but the mechanisms were previously unclear. Here, we show that the pathogen secretes an amylase (LamA) enzyme that rapidly breakdowns glycogen stores within neutrophils, and this triggers increased glycolysis. Subsequently, the two major killing mechanisms of neutrophils, granule fusion and production of reactive oxygen species, are activated, resulting in rapid killing of L. pneumophila.
Assuntos
Legionella pneumophila/imunologia , Neutrófilos/microbiologia , Sistemas de Secreção Tipo IV/imunologia , Proteínas de Bactérias/metabolismo , Citosol/microbiologia , Glicogênio/metabolismo , Glicólise , Humanos , Legionella pneumophila/genética , Legionella pneumophila/metabolismo , Doença dos Legionários/microbiologia , Fagossomos/imunologia , Fagossomos/microbiologia , Espécies Reativas de Oxigênio/imunologia , Sistemas de Secreção Tipo IV/genéticaRESUMO
BACKGROUND: Patients are susceptible to immunosuppression in late-stage of sepsis, in which myeloid-derived suppressor cells (MDSCs) is an important contributor. This study aims to investigate whether all-trans-retinoic acid (ATRA), which has been proved to inhibit MDSCs generation in cancer, will ameliorate sepsis-induced immuno-suppression through modulating MDSCs. METHODS: A clinically relevant "two-hit'' model of sepsis, the cecal ligation and puncture (CLP) model and secondary pneumonia model, were established in mice. The effects of ATRA on the mortality, the bacterial burden, the expansion and activity of CLP-induced MDSCs, as well as the function of CD4+ T cells were evaluated. RESULTS: In CLP model, ATRA was found to reduce frequency of MDSCs in spleen of mice and inhibit activity of MDSCs by regulating the generation and activity of arginase-1 and iNOS, and the secretion of immune-supressive cytokines. ATRA administration eventually reduced mortality of secondary infection by Legionella pneumophila in CLP-surviving mice, which might be associated with the restoration of CD4+ T cells proliferating and secreting activity. CONCLUSION: ATRA can restore CD4+ T cells dysfunction in sepsis by modulating the expansion and function of MDSCs and therefore provides a potential therapy that targets the immunosuppressive state of sepsis.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Legionella pneumophila/imunologia , Células Supressoras Mieloides/imunologia , Sepse/imunologia , Tretinoína/farmacologia , Animais , Arginase/metabolismo , Citocinas/metabolismo , Doença dos Legionários/imunologia , Doença dos Legionários/mortalidade , Camundongos , Camundongos Endogâmicos C57BL , Células Supressoras Mieloides/citologia , Células Supressoras Mieloides/efeitos dos fármacos , Óxido Nítrico Sintase Tipo II/metabolismo , Sepse/microbiologia , Sepse/patologiaRESUMO
The human pulmonary environment is complex, containing a matrix of cells, including fibroblasts, epithelial cells, interstitial macrophages, alveolar macrophages and neutrophils. When confronted with foreign material or invading pathogens, these cells mount a robust response. Nevertheless, many bacterial pathogens with an intracellular lifecycle stage exploit this environment for replication and survival. These include, but are not limited to, Coxiella burnetii, Legionella pneumophila, Yersinia pestis, Mycobacterium tuberculosis and Staphylococcus aureus. Currently, few human disease-relevant model systems exist for studying host-pathogen interactions during these bacterial infections in the lung. Here, we present two novel infection platforms, human alveolar macrophages (hAMs) and human precision-cut lung slices (hPCLS), along with an up-to-date synopsis of research using said models. Additionally, alternative uses for these systems in the absence of pathogen involvement are presented, such as tissue banking and further characterization of the human lung environment. Overall, hAMs and hPCLS allow novel human disease-relevant investigations that other models, such as cell lines and animal models, cannot completely provide.
Assuntos
Infecções Bacterianas/microbiologia , Interações Hospedeiro-Patógeno/imunologia , Pneumopatias/microbiologia , Pulmão/microbiologia , Macrófagos Alveolares/microbiologia , Modelos Biológicos , Infecções Bacterianas/imunologia , Infecções Bacterianas/patologia , Coxiella burnetii/crescimento & desenvolvimento , Coxiella burnetii/imunologia , Coxiella burnetii/patogenicidade , Humanos , Legionella pneumophila/crescimento & desenvolvimento , Legionella pneumophila/imunologia , Legionella pneumophila/patogenicidade , Pulmão/imunologia , Pulmão/patologia , Pneumopatias/imunologia , Pneumopatias/patologia , Macrófagos Alveolares/imunologia , Macrófagos Alveolares/patologia , Microtomia , Mycobacterium tuberculosis/crescimento & desenvolvimento , Mycobacterium tuberculosis/imunologia , Mycobacterium tuberculosis/patogenicidade , Cultura Primária de Células , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/imunologia , Staphylococcus aureus/patogenicidade , Bancos de Tecidos , Técnicas de Cultura de Tecidos , Yersinia pestis/crescimento & desenvolvimento , Yersinia pestis/imunologia , Yersinia pestis/patogenicidadeRESUMO
Bryan D. Bryson works in the field of biological engineering with a specific interest in host-mycobacterium interactions. In this mSphere of Influence article, he reflects on how "IRG1 and inducible nitric oxide synthase act redundantly with other interferon-gamma-induced factors to restrict intracellular replication of Legionella pneumophila" by Price and colleagues (J. V. Price, D. Russo, D. X. Ji, R. A. Chavez, et al., mBio 10:e02629-19, 2019, https://doi.org/10.1128/mBio.02629-19) made an impact on him by reinforcing the complexity of intracellular pathogen control.
Assuntos
Interações Hospedeiro-Patógeno , Imunidade Inata/genética , Interferon gama/imunologia , Legionella pneumophila/imunologia , Interações Hospedeiro-Patógeno/genética , Interações Hospedeiro-Patógeno/imunologia , Humanos , Legionella pneumophila/patogenicidade , Narração , Óxido Nítrico Sintase Tipo II , Fagossomos/imunologia , Fagossomos/microbiologia , Transporte ProteicoRESUMO
BACKGROUND: Legionnaire's disease is one of the major causes of community-acquired pneumonia and is occasionally complicated by neurological symptoms. However, reports of ocular lesions due to Legionnaire's disease are limited. CASE PRESENTATION: We report the case of a patient with Legionnaire's disease presenting as bilateral central scotomata due to retinal lesions. The patient consulted due to fever and bilateral central scotomata, as well as other extrapulmonary symptoms. Optical coherence tomography (OCT) showed bilateral accumulations of fluid under the retina, and the patient was diagnosed with bilateral exudative retinal detachment. Later, Legionnaire's disease was confirmed by pulmonary infiltrates on chest imaging and positive urinary antigen for Legionella pneumophila. After administration of antibiotics, the bilateral central scotomata and bilateral subretinal fluid accumulations completely resolved, as did the other extrapulmonary symptoms and the pulmonary infiltrates. Thus, the bilateral central scotomata due to exudative retinal detachment were thought to be caused by Legionnaire's disease. CONCLUSIONS: This case demonstrates that Legionnaire's disease can present as bilateral central scotomata. We may consider the possibility of extrapulmonary involvement complicating Legionnaire's disease when we encounter bilateral ocular lesions in patients with fever and pneumonia.
Assuntos
Doença dos Legionários/diagnóstico , Doença dos Legionários/fisiopatologia , Escotoma/etiologia , Antibacterianos/uso terapêutico , Humanos , Legionella pneumophila/imunologia , Legionella pneumophila/patogenicidade , Doença dos Legionários/tratamento farmacológico , Doença dos Legionários/etiologia , Masculino , Pessoa de Meia-Idade , Pneumonia Bacteriana/diagnóstico , Pneumonia Bacteriana/tratamento farmacológico , Pneumonia Bacteriana/etiologia , Pneumonia Bacteriana/fisiopatologia , Escotoma/diagnóstico , Escotoma/patologia , Tomografia de Coerência ÓpticaRESUMO
BACKGROUND: Legionella spp. can cause severe pneumonia and most Legionella pneumonia (LP) cases are diagnosed using the urine antigen test (UAT). However, diagnosis of LP with negative UAT results (LPNUAT) is challenging. We investigated the clinical and radiological features of LPNUAT. METHODS: We retrospectively collected LP cases with positive UAT (LPPUAT) and cases of suspected LP with negative UAT that were examined by Legionella culture between July 2014 and March 2020. We investigated the clinical and CT findings for LP that showed negative UAT results and was diagnosed by culture and compared these findings with those for other pneumonias suspicious for LP with negative results in UAT and Legionella culture (OPSLP). RESULTS: Eight LPNUAT, 20 LPPUAT, and 19 OPSLP cases were included in this study. There were no significant differences in the clinical and CT findings between LPPUAT and LPNUAT when examined by UAT. In LPNUAT, dyspnea, renal dysfunction, liver dysfunction, and bilateral lesions were more commonly observed and inflammatory changes and the number of affected lobes were significantly higher when examined by culture than when examined by UAT. Comparison to OPSLP, LPNUAT did not show such differences, but rather showed disturbances in consciousness, hyponatremia and rhabdomyolysis. Furthermore, lobar consolidation was observed more frequently and bronchial wall thickening and centrilobular nodules were observed less frequently in LPNUAT. CONCLUSIONS: LP characteristics such as disturbance of consciousness, hyponatremia, rhabdomyolysis, lobar consolidation, and less bronchial wall thickening and centrilobular nodule contribute to the diagnosis of LP in patients with negative UAT results.
Assuntos
Antígenos de Bactérias/urina , Testes Imunológicos/métodos , Doença dos Legionários/diagnóstico por imagem , Resultados Negativos , Tomografia Computadorizada por Raios X , Adulto , Idoso , Biomarcadores/urina , Feminino , Humanos , Legionella pneumophila/imunologia , Legionella pneumophila/isolamento & purificação , Doença dos Legionários/diagnóstico , Doença dos Legionários/microbiologia , Masculino , Pessoa de Meia-Idade , Estudos RetrospectivosRESUMO
OBJECTIVES: The aim of this study was to evaluate the diagnostic utility of a novel test kit that could theoretically detect all serogroups of Legionella pneumophila for diagnosing Legionella pneumonia, in comparison with existing kits. METHODS: This study was conducted in 16 hospitals in Japan from April 2016 to December 2018. Three urinary antigen test kits were used: the novel kit (LAC-116), BinaxNOW Legionella (Binax), and Q-line Kyokutou Legionella (Q-line). In addition, sputum culture and nucleic acid detection tests and serum antibody tests were performed where possible. The diagnostic accuracy and correlations of the novel kit with the two existing kits were analyzed. RESULTS: In total, 56 patients were diagnosed with Legionella pneumonia. The sensitivities of LAC-116, Binax, and Q-line were 79%, 84%, and 71%, respectively. The overall match rate between LAC-116 and Binax was 96.8% and between LAC-116 and Q-line was 96.4%. One patient had L. pneumophila serogroup 2, and only LAC-116 showed a positive result, whereas Binax and Q-line did not. CONCLUSIONS: The novel Legionella urinary antigen test kit was useful for diagnosing Legionella pneumonia. In addition, it could detect Legionella pneumonia caused by non-L. pneumophila serogroup 1.
Assuntos
Antígenos de Bactérias/análise , Legionella pneumophila/classificação , Doença dos Legionários/diagnóstico , Idoso , Antígenos de Bactérias/urina , Feminino , Humanos , Japão , Legionella pneumophila/imunologia , Legionella pneumophila/isolamento & purificação , Masculino , Pessoa de Meia-Idade , Kit de Reagentes para Diagnóstico , Sensibilidade e Especificidade , SorogrupoRESUMO
Legionella pneumophila, an intracellular bacterium, may cause life-threatening pneumonia in immunocompromised individuals. Mononuclear cells and antibodies have been reported to be associated with the host defense response against L. pneumophila. This study is to determine whether Legionella peptidoglycan-associated lipoprotein (PAL)-specific CD8+ T cells are directly associated with protection against L. pneumophila, with a focus on potential epitopes. Synthetic peptides derived from PAL of L. pneumophila were obtained and tested through in vitro and in vivo cytotoxic T lymphocyte (CTL) assays for immunogenicity. PAL DNA vaccines or a peptide epitope with or without CpG-oligodeoxynucleotides (ODN) was evaluated for protection against L. pneumophila infection in animal models. When mice were immunized with DNA vaccines expressing the PAL of L. pneumophila, they were significantly protected against a lethal challenge with L. pneumophila through induction of antigen-specific CD8+ CTLs. Of the 13 PAL peptides tested, PAL92-100 (EYLKTHPGA) was the most immunogenic and induced the strongest CTL responses. When mice were immunized with the PAL92-100 peptide plus CpG-ODN, they were protected against the lethal challenge, while control mice died within 3-6 days after the challenge. Consistent with lung tissue histological data, bacterial counts in the lungs of immunized mice were significantly lower than those in control mice. Also, the amino acid sequence of PAL92-100 peptides is conserved among various Legionella species. To our knowledge, this study is the first to demonstrate that PAL92-100-specific CD8+ T cells play a central role in the host defense response against L. pneumophila.
Assuntos
Proteínas da Membrana Bacteriana Externa/administração & dosagem , Vacinas Bacterianas/administração & dosagem , Epitopos , Legionella pneumophila/imunologia , Doença dos Legionários/prevenção & controle , Pulmão/imunologia , Fragmentos de Peptídeos/administração & dosagem , Proteoglicanas/administração & dosagem , Linfócitos T Citotóxicos/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Carga Bacteriana , Proteínas da Membrana Bacteriana Externa/imunologia , Vacinas Bacterianas/imunologia , Células Cultivadas , Citocinas/metabolismo , Feminino , Interações Hospedeiro-Patógeno , Imunização , Doença dos Legionários/imunologia , Doença dos Legionários/metabolismo , Doença dos Legionários/microbiologia , Pulmão/metabolismo , Pulmão/microbiologia , Pulmão/patologia , Ativação Linfocitária , Camundongos Endogâmicos BALB C , Oligodesoxirribonucleotídeos/administração & dosagem , Fragmentos de Peptídeos/imunologia , Proteoglicanas/imunologia , Linfócitos T Citotóxicos/metabolismo , Linfócitos T Citotóxicos/microbiologiaRESUMO
INTRODUCTION: Sources of infection of most cases of community-acquired Legionnaires' disease (CALD) are unknown. OBJECTIVE: Identification of sources of infection of CALD. SETTING: Berlin; December 2016-May 2019. PARTICIPANTS: Adult cases of CALD reported to district health authorities and consenting to the study; age and hospital matched controls. MAIN OUTCOME MEASURE: Percentage of cases of CALD with attributed source of infection. METHODS: Analysis of secondary patient samples for monoclonal antibody (MAb) type (and sequence type); questionnaire-based interviews, analysis of standard household water samples for Legionella concentration followed by MAb (and sequence) typing of Legionella pneumophila serogroup 1 (Lp1) isolates; among cases taking of additional water samples to identify the infectious source as appropriate; recruitment of control persons for comparison of exposure history and Legionella in standard household water samples. For each case an appraisal matrix was filled in to attribute any of three source types (external (non-residence) source, residential non-drinking water (RnDW) source (not directly from drinking water outlet), residential drinking water (RDW) as source) using three evidence types (microbiological results, cluster evidence, analytical-comparative evidence (using added information from controls)). RESULTS: Inclusion of 111 study cases and 202 controls. Median age of cases was 67 years (range 25-93 years), 74 (67%) were male. Among 65 patients with urine typable for MAb type we found a MAb 3/1-positive strain in all of them. Compared to controls being a case was not associated with a higher Legionella concentration in standard household water samples, however, the presence of a MAb 3/1-positive strain was significantly associated (odds ratio (OR) = 4.9, 95% confidence interval (CI) 1.7 to 11). Thus, a source was attributed by microbiological evidence if it contained a MAb 3/1-positive strain. A source was attributed by cluster evidence if at least two cases were exposed to the same source. Statistically significant general source types were attributed by calculating the population attributable risk (analytical-comparative evidence). We identified an external source in 16 (14%) cases, and RDW as source in 28 (25%). Wearing inadequately disinfected dentures was the only RnDW source significantly associated with cases (OR = 3.2, 95% CI 1.3 to 7.8) and led to an additional 8% of cases with source attribution, for a total of 48% of cases attributed. CONCLUSION: Using the appraisal matrix we attributed almost half of all cases of CALD to an infectious source, predominantly RDW. Risk for LD seems to be conferred primarily by the type of Legionella rather than the amount. Dentures as a new infectious source needs further, in particular, integrated microbiological, molecular and epidemiological confirmation.
Assuntos
Legionella pneumophila/isolamento & purificação , Doença dos Legionários/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Monoclonais/imunologia , Berlim/epidemiologia , Estudos de Casos e Controles , Infecções Comunitárias Adquiridas/diagnóstico , Infecções Comunitárias Adquiridas/epidemiologia , Infecções Comunitárias Adquiridas/microbiologia , Dentaduras/microbiologia , Desinfetantes/farmacologia , Água Potável/microbiologia , Feminino , Humanos , Legionella pneumophila/efeitos dos fármacos , Legionella pneumophila/imunologia , Doença dos Legionários/epidemiologia , Doença dos Legionários/microbiologia , Masculino , Pessoa de Meia-Idade , Razão de Chances , Fatores de Risco , Microbiologia da ÁguaRESUMO
Legionella pneumophila is a flagellated pathogenic bacterium that causes atypical pneumonia called Legionnaires' disease. The flagellum plays a key role in the pathogenesis of L. pneumophila in the host. The protein FlgL forms a junction between the flagellar hook and filament and has been reported to elicit the host humoral immune response. To provide structural insights into FlgL-mediated junction assembly and FlgL-based vaccine design, we performed structural and serological studies on L. pneumophila FlgL (lpFlgL). The crystal structure of a truncated lpFlgL protein that consists of the D1 and D2 domains was determined at 3.06 Å resolution. The D1 domain of lpFlgL adopts a primarily helical, rod-shaped structure, and the D2 domain folds into a ß-sandwich structure that is affixed to the upper region of the D1 domain. The D1 domain of lpFlgL exhibits structural similarity to the flagellar filament protein flagellin, allowing us to propose a structural model of the lpFlgL junction based on the polymeric structure of flagellin. Furthermore, the D1 domain of lpFlgL exhibited substantially higher protein stability than the D2 domain and was responsible for most of the antigenicity of lpFlgL, suggesting that the D1 domain of lpFlgL would be a suitable target for the development of an anti-L. pneumophila vaccine.