RESUMO
The Klebsiella oxytoca species complex is part of the human microbiome, especially during infancy and childhood. K. oxytoca species complex strains can produce enterotoxins, namely, tilimycin and tilivalline, while also contributing to colonization resistance (CR). The relationship between these seemingly contradictory roles is not well understood. Here, by coupling ex vivo assays with CRISPR-mutagenesis and various mouse models, we show that K. oxytoca provides CR against Salmonella Typhimurium. In vitro, the antimicrobial activity against various Salmonella strains depended on tilimycin production and was induced by various simple carbohydrates. In vivo, CR against Salmonella depended on toxin production in germ-free mice, while it was largely toxin-independent in mice with residual microbiota. This was linked to the relative levels of toxin-inducing carbohydrates in vivo. Finally, dulcitol utilization was essential for toxin-independent CR in gnotobiotic mice. Together, this demonstrates that nutrient availability is key to both toxin-dependent and substrate-driven competition between K. oxytoca and Salmonella.
Assuntos
Klebsiella oxytoca , Infecções por Salmonella , Salmonella typhimurium , Klebsiella oxytoca/genética , Klebsiella oxytoca/metabolismo , Animais , Camundongos , Infecções por Salmonella/microbiologia , Salmonella typhimurium/genética , Salmonella typhimurium/metabolismo , Salmonella typhimurium/crescimento & desenvolvimento , Salmonella typhimurium/efeitos dos fármacos , Humanos , Modelos Animais de Doenças , Enterotoxinas/metabolismo , Enterotoxinas/genética , Feminino , Camundongos Endogâmicos C57BL , Infecções por Klebsiella/microbiologia , Microbiota , Microbioma Gastrointestinal , Antibiose , BenzodiazepinonasRESUMO
Gut-draining mesenteric and celiac lymph nodes (mLNs and celLNs) critically contribute to peripheral tolerance toward food and microbial antigens by supporting the de novo induction of regulatory T cells (Tregs). These tolerogenic properties of mLNs and celLNs are stably imprinted within stromal cells (SCs) by microbial signals and vitamin A (VA), respectively. Here, we report that a single, transient gastrointestinal infection in the neonatal, but not adult, period durably abrogates the efficient Treg-inducing capacity of celLNs by altering the subset composition and gene expression profile of celLNSCs. These cells carry information about the early-life pathogen encounter until adulthood and durably instruct migratory dendritic cells entering the celLN with reduced tolerogenic properties. Mechanistically, transiently reduced VA levels cause long-lasting celLN functional impairment, which can be rescued by early-life treatment with VA. Together, our data highlight the therapeutic potential of VA to prevent sequelae post gastrointestinal infections in infants.
Assuntos
Linfonodos , Linfócitos T Reguladores , Vitamina A , Animais , Linfonodos/imunologia , Linfonodos/patologia , Linfonodos/efeitos dos fármacos , Vitamina A/farmacologia , Vitamina A/uso terapêutico , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/efeitos dos fármacos , Camundongos , Animais Recém-Nascidos , Tolerância Imunológica/efeitos dos fármacos , Células Dendríticas/imunologia , Camundongos Endogâmicos C57BL , FemininoRESUMO
IMPORTANCE: There is a strong need to find novel treatment options against urinary tract infections associated with antimicrobial resistance. This study evaluates two atypical tetracyclines, namely chelocardin (CHD) and amidochelocardin (CDCHD), with respect to their pharmacokinetics and pharmacodynamics. We show CHD and CDCHD are cleared at high concentrations in mouse urine. Especially, CDCHD is highly effective in an ascending urinary tract infection model, suggesting further preclinical evaluation.
Assuntos
Antibacterianos , Infecções Urinárias , Animais , Camundongos , Testes de Sensibilidade Microbiana , Antibacterianos/uso terapêutico , Antibacterianos/farmacocinética , Tetraciclinas/farmacologia , Tetraciclinas/uso terapêutico , Infecções Urinárias/tratamento farmacológicoRESUMO
As of now, the COVID-19 pandemic has spread to over 770 million confirmed cases and caused approximately 7 million deaths. While several vaccines and monoclonal antibodies (mAb) have been developed and deployed, natural selection against immune recognition of viral antigens by antibodies has fueled the evolution of new emerging variants and limited the immune protection by vaccines and mAb. To optimize the efficiency of mAb, it is imperative to understand how they neutralize the variants of concern (VoCs) and to investigate the mutations responsible for immune escape. In this study, we show the in vitro neutralizing effects of a previously described monoclonal antibody (STE90-C11) against the SARS-CoV-2 Delta variant (B.1.617.2) and its in vivo effects in therapeutic and prophylactic settings. We also show that the Omicron variant avoids recognition by this mAb. To define which mutations are responsible for the escape in the Omicron variant, we used a library of pseudovirus mutants carrying each of the mutations present in the Omicron VoC individually. We show that either 501Y or 417K point mutations were sufficient for the escape of Omicron recognition by STE90-C11. To test how escape mutations act against a combination of antibodies, we tested the same library against bispecific antibodies, recognizing two discrete regions of the spike antigen. While Omicron escaped the control by the bispecific antibodies, the same antibodies controlled all mutants with individual mutations.
Assuntos
Anticorpos Biespecíficos , COVID-19 , Hepatite D , Vacinas , Humanos , Anticorpos Neutralizantes , SARS-CoV-2/genética , Pandemias , Anticorpos Monoclonais , Anticorpos Antivirais , Glicoproteína da Espícula de Coronavírus/genéticaRESUMO
Mucosal barrier integrity and pathogen clearance is a complex process influenced by both Th17 and Treg cells. Previously, we had described the DNA methylation profile of Th17 cells and identified Zinc finger protein (Zfp)362 to be uniquely demethylated. Here, we generated Zfp362-/- mice to unravel the role of Zfp362 for Th17 cell biology. Zfp362-/- mice appeared clinically normal, showed no phenotypic alterations in the T-cell compartment, and upon colonization with segmented filamentous bacteria, no effect of Zfp362 deficiency on Th17 cell differentiation was observed. By contrast, Zfp362 deletion resulted in increased frequencies of colonic Foxp3+ Treg cells and IL-10+ and RORγt+ Treg cell subsets in mesenteric lymph nodes. Adoptive transfer of naïve CD4+ T cells from Zfp362-/- mice into Rag2-/- mice resulted in a significantly lower weight loss when compared with controls receiving cells from Zfp362+/+ littermates. However, this attenuated weight loss did not correlate with alterations of Th17 cells but instead was associated with an increase of effector Treg cells in mesenteric lymph nodes. Together, these results suggest that Zfp362 plays an important role in promoting colonic inflammation; however, this function is derived from constraining the effector function of Treg cells rather than directly promoting Th17 cell differentiation.
Assuntos
Linfócitos T Reguladores , Células Th17 , Camundongos , Animais , Linfócitos T Reguladores/metabolismo , Células Th17/metabolismo , Diferenciação Celular , Inflamação/metabolismo , Redução de Peso , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/metabolismoRESUMO
Transfer of the gut microbiota from wild to laboratory mice alters the host's immune status and enhances resistance to infectious and metabolic diseases, but understanding of which microbes and how they promote host fitness is only emerging. Our analysis of metagenomic sequencing data reveals that Helicobacter spp. are enriched in wild compared with specific-pathogen-free (SPF) and conventionally housed mice, with multiple species commonly co-colonizing their hosts. We create laboratory mice harboring three non-SPF Helicobacter spp. to evaluate their effect on mucosal immunity and colonization resistance to the enteropathogen Citrobacter rodentium. Our experiments reveal that Helicobacter spp. interfere with C. rodentium colonization and attenuate C. rodentium-induced gut inflammation in wild-type (WT) mice, even preventing lethal infection in Rag2-/- SPF mice. Further analyses suggest that Helicobacter spp. interfere with tissue attachment of C. rodentium, putatively by reducing the availability of mucus-derived sugars. These results unveil pivotal protective functions of wild mouse microbiota constituents against intestinal infection.
Assuntos
Infecções por Enterobacteriaceae , Microbioma Gastrointestinal , Microbiota , Animais , Camundongos , Citrobacter rodentium , Imunidade Adaptativa , Camundongos Endogâmicos C57BLRESUMO
The COVID-19 pandemic remains a global health threat and novel antiviral strategies are urgently needed. SARS-CoV-2 employs the cellular serine protease TMPRSS2 for entry into lung cells, and TMPRSS2 inhibitors are being developed for COVID-19 therapy. However, the SARS-CoV-2 Omicron variant, which currently dominates the pandemic, prefers the endo/lysosomal cysteine protease cathepsin L over TMPRSS2 for cell entry, raising doubts as to whether TMPRSS2 inhibitors would be suitable for the treatment of patients infected with the Omicron variant. Nevertheless, the contribution of TMPRSS2 to the spread of SARS-CoV-2 in the infected host is largely unclear. In this study, we show that the loss of TMPRSS2 strongly reduced the replication of the Beta variant in the nose, trachea and lung of C57BL/6 mice, and protected the animals from weight loss and disease. The infection of mice with the Omicron variant did not cause disease, as expected, but again, TMPRSS2 was essential for efficient viral spread in the upper and lower respiratory tract. These results identify the key role of TMPRSS2 in SARS-CoV-2 Beta and Omicron infection, and highlight TMPRSS2 as an attractive target for antiviral intervention.
Assuntos
COVID-19 , SARS-CoV-2 , Animais , Humanos , Camundongos , Antivirais/farmacologia , Antivirais/uso terapêutico , Camundongos Endogâmicos C57BL , Pandemias , Serina Endopeptidases/genéticaRESUMO
[This corrects the article DOI: 10.1371/journal.ppat.1010219.].
RESUMO
Excessive inflammation is a major cause of morbidity and mortality in many viral infections including influenza. Therefore, there is a need for therapeutic interventions that dampen and redirect inflammatory responses and, ideally, exert antiviral effects. Itaconate is an immunomodulatory metabolite which also reprograms cell metabolism and inflammatory responses when applied exogenously. We evaluated effects of endogenous itaconate and exogenous application of itaconate and its variants dimethyl- and 4-octyl-itaconate (DI, 4OI) on host responses to influenza A virus (IAV). Infection induced expression of ACOD1, the enzyme catalyzing itaconate synthesis, in monocytes and macrophages, which correlated with viral replication and was abrogated by DI and 4OI treatment. In IAV-infected mice, pulmonary inflammation and weight loss were greater in Acod1-/- than in wild-type mice, and DI treatment reduced pulmonary inflammation and mortality. The compounds reversed infection-triggered interferon responses and modulated inflammation in human cells supporting non-productive and productive infection, in peripheral blood mononuclear cells, and in human lung tissue. All three itaconates reduced ROS levels and STAT1 phosphorylation, whereas AKT phosphorylation was reduced by 4OI and DI but increased by itaconate. Single-cell RNA sequencing identified monocytes as the main target of infection and the exclusive source of ACOD1 mRNA in peripheral blood. DI treatment silenced IFN-responses predominantly in monocytes, but also in lymphocytes and natural killer cells. Ectopic synthesis of itaconate in A549 cells, which do not physiologically express ACOD1, reduced infection-driven inflammation, and DI reduced IAV- and IFNγ-induced CXCL10 expression in murine macrophages independent of the presence of endogenous ACOD1. The compounds differed greatly in their effects on cellular gene homeostasis and released cytokines/chemokines, but all three markedly reduced release of the pro-inflammatory chemokines CXCL10 (IP-10) and CCL2 (MCP-1). Viral replication did not increase under treatment despite the dramatically repressed IFN responses. In fact, 4OI strongly inhibited viral transcription in peripheral blood mononuclear cells, and the compounds reduced viral titers (4OI>Ita>DI) in A549 cells whereas viral transcription was unaffected. Taken together, these results reveal itaconates as immunomodulatory and antiviral interventions for influenza virus infection.
Assuntos
Vírus da Influenza A/imunologia , Macrófagos/imunologia , Infecções por Orthomyxoviridae/tratamento farmacológico , Succinatos/farmacologia , Células A549 , Animais , Carboxiliases/deficiência , Carboxiliases/imunologia , Citocinas/genética , Citocinas/imunologia , Humanos , Macrófagos/virologia , Camundongos , Camundongos Knockout , Infecções por Orthomyxoviridae/genética , Infecções por Orthomyxoviridae/imunologia , Células THP-1RESUMO
Gut colonization with multidrug-resistant (MDR) bacteria enhances the risk of bloodstream infections in susceptible individuals. We demonstrate highly variable degrees of ex vivo colonization resistance against a carbapenem-resistant Klebsiella pneumoniae strain in human feces samples and subsequently isolate diverse K. oxytoca strains from protected donors. Several of these K. oxytoca strains reduce gut colonization of MDR K. pneumoniae strains in antibiotic-treated and gnotobiotic mouse models. Comparative analysis of K. oxytoca strains coupled with CRISPR-Cas9-mediated deletion of casA, a protein essential for utilization of selected beta-glucosides, identified competition for specific carbohydrates as key in promoting colonization resistance. In addition to direct competition between K. oxytoca and K. pneumoniae, cooperation with additional commensals is required to reestablish full colonization resistance and gut decolonization. Finally, humanized microbiota mice generated from K. pneumoniae-susceptible donors are protected by K. oxytoca administration, demonstrating the potential of commensal K. oxytoca strains as next-generation probiotics.
Assuntos
Metabolismo dos Carboidratos , Fezes/microbiologia , Trato Gastrointestinal/microbiologia , Klebsiella oxytoca/fisiologia , Klebsiella pneumoniae/crescimento & desenvolvimento , Interações Microbianas , Imunidade Adaptativa , Adulto , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Criança , Farmacorresistência Bacteriana Múltipla , Microbioma Gastrointestinal , Vida Livre de Germes , Glucosídeos/metabolismo , Humanos , Infecções por Klebsiella/imunologia , Infecções por Klebsiella/microbiologia , Klebsiella oxytoca/genética , Klebsiella oxytoca/isolamento & purificação , Klebsiella pneumoniae/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BLRESUMO
Autophagy is an evolutionary conserved catabolic pathway that ensures the degradation of intracellular components. The autophagic pathway is regulated by autophagy-related (Atg) proteins that govern formation of double-membraned vesicles called autophagosomes. Autophagy deficiency in regulatory T (Treg) cells leads to increased apoptosis of these cells and to the development of autoimmune disorders, predominantly characterized by intestinal inflammation. Recently, RORγt-expressing Treg cells have been identified as key regulators of gut homeostasis, preventing intestinal immunopathology. To study the role of autophagy in RORγt+ Foxp3+ Treg cells, we generated mice lacking the essential component of the core autophagy machinery Atg5 in Foxp3+ cells. Atg5 deficiency in Treg cells led to a predominant intestinal inflammation. While Atg5-deficient Treg cells were reduced in peripheral lymphoid organs, the intestinal RORγt+ Foxp3+ subpopulation of Treg cells was most severely affected. Our data indicated that autophagy is essential to maintain the intestinal RORγt+ Foxp3+ Treg population, thereby protecting the mice from gut inflammatory disorders.
Assuntos
Proteína 5 Relacionada à Autofagia/imunologia , Microbioma Gastrointestinal/imunologia , Homeostase/imunologia , Mucosa Intestinal/imunologia , Linfócitos T Reguladores/imunologia , Animais , Proteína 5 Relacionada à Autofagia/genética , Fatores de Transcrição Forkhead/genética , Fatores de Transcrição Forkhead/imunologia , Homeostase/genética , Camundongos , Camundongos Transgênicos , Membro 3 do Grupo F da Subfamília 1 de Receptores NuclearesRESUMO
The occurrence and spread of multidrug-resistant pathogens, especially bacteria from the ESKAPE panel, increases the risk to succumb to untreatable infections. We developed a novel antimicrobial peptide, Pam-3, with antibacterial and antibiofilm properties to counter this threat. The peptide is based on an eight-amino acid carboxyl-terminal fragment of human ß-defensin 1. Pam-3 exhibited prominent antimicrobial activity against multidrug-resistant ESKAPE pathogens and additionally eradicated already established biofilms in vitro, primarily by disrupting membrane integrity of its target cell. Importantly, prolonged exposure did not result in drug-resistance to Pam-3. In mouse models, Pam-3 selectively reduced acute intestinal Salmonella and established Citrobacter infections, without compromising the core microbiota, hence displaying an added benefit to traditional broad-spectrum antibiotics. In conclusion, our data support the development of defensin-derived antimicrobial agents as a novel approach to fight multidrug-resistant bacteria, where Pam-3 appears as a particularly promising microbiota-preserving candidate.
Assuntos
Infecções por Enterobacteriaceae/tratamento farmacológico , Gastroenteropatias/tratamento farmacológico , Microbioma Gastrointestinal/efeitos dos fármacos , Salmonelose Animal/tratamento farmacológico , Animais , Biofilmes/efeitos dos fármacos , Modelos Animais de Doenças , Farmacorresistência Bacteriana Múltipla , Feminino , Masculino , Camundongos Endogâmicos C57BL , Testes de Sensibilidade MicrobianaRESUMO
Diverse microbial signatures within the intestinal microbiota have been associated with intestinal and systemic inflammatory diseases, but whether these candidate microbes actively modulate host phenotypes or passively expand within the altered microbial ecosystem is frequently not known. Here we demonstrate that colonization of mice with a member of the genus Prevotella, which has been previously associated to colitis in mice, exacerbates intestinal inflammation. Our analysis revealed that Prevotella intestinalis alters composition and function of the ecosystem resulting in a reduction of short-chain fatty acids, specifically acetate, and consequently a decrease in intestinal IL-18 levels during steady state. Supplementation of IL-18 to Prevotella-colonized mice was sufficient to reduce intestinal inflammation. Hence, we conclude that intestinal Prevotella colonization results in metabolic changes in the microbiota, which reduce IL-18 production and consequently exacerbate intestinal inflammation, and potential systemic autoimmunity.
Assuntos
Infecções por Bacteroidaceae/imunologia , Infecções por Bacteroidaceae/microbiologia , Microbioma Gastrointestinal/imunologia , Interações Hospedeiro-Patógeno/imunologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Prevotella/imunologia , Imunidade Adaptativa , Animais , Citocinas/metabolismo , Modelos Animais de Doenças , Suscetibilidade a Doenças , Mediadores da Inflamação/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patologia , Metagenoma , Metagenômica/métodos , Camundongos , Camundongos Knockout , Mucosite/etiologia , Mucosite/metabolismo , Mucosite/patologiaRESUMO
The composition of the intestinal microbiota influences the outcome of enteric infections in human and mice. However, the role of specific members and their metabolites contributing to disease severity is largely unknown. Using isogenic mouse lines harboring distinct microbiota communities, we observed highly variable disease kinetics of enteric Citrobacter rodentium colonization after infection. Transfer of communities from susceptible and resistant mice into germ-free mice verified that the varying susceptibilities are determined by microbiota composition. The strongest differences in colonization were observed in the cecum and could be maintained in vitro by coculturing cecal bacteria with C. rodentium. Cohousing of animals as well as the transfer of cultivable bacteria from resistant to susceptible mice led to variable outcomes in the recipient mice. Microbiome analysis revealed that a higher abundance of butyrate-producing bacteria was associated with the resistant phenotype. Quantification of short-chain fatty acid (SCFA) levels before and after infection revealed increased concentrations of acetate, butyrate and propionate in mice with delayed colonization. Addition of physiological concentrations of butyrate, but not of acetate and/or propionate strongly impaired growth of C. rodentium in vitro. In vivo supplementation of susceptible, antibiotic-treated and germ-free mice with butyrate led to the same level of protection, notably only when cecal butyrate concentration reached a concentration higher than 50 nmol/mg indicating a critical threshold for protection. In the recent years, commensal-derived primary and secondary bacterial metabolites emerged as potent modulators of hosts susceptibility to infection. Our results provide evidence that variations in SCFA production in mice fed fibre-rich chow-based diets modulate susceptibility to colonization with Enterobacteriaceae not only in antibiotic-disturbed ecosystems but even in undisturbed microbial communities. These findings emphasise the need for microbiota normalization across laboratory mouse lines for infection experiments with the model-pathogen C. rodentium independent of investigations of diet and antibiotic usage.
Assuntos
Citrobacter rodentium/crescimento & desenvolvimento , Infecções por Enterobacteriaceae/metabolismo , Ácidos Graxos/metabolismo , Microbioma Gastrointestinal , Animais , CamundongosRESUMO
Acute lower respiratory tract infections (ALRI) caused by respiratory syncytial virus (RSV) are associated with a severe disease burden among infants and elderly patients. Treatment options are limited. While numerous drug candidates with different viral targets are under development, the utility of RSV entry inhibitors is challenged by a low resistance barrier and by single mutations causing cross-resistance against a wide spectrum of fusion inhibitor chemotypes. We developed a cell-based screening assay for discovery of compounds inhibiting infection with primary RSV isolates. Using this system, we identified labyrinthopeptin A1 and A2 (Laby A1/A2), lantibiotics isolated from Actinomadura namibiensis, as effective RSV cell entry inhibitors with IC50s of 0.39 µM and 4.97 µM, respectively, and with favourable therapeutic index (>200 and > 20, respectively). Both molecules were active against multiple RSV strains including primary isolates and their antiviral activity against RSV was confirmed in primary human airway cells ex vivo and a murine model in vivo. Laby A1/A2 were antiviral in prophylactic and therapeutic treatment regimens and displayed synergistic activity when applied in combination with each other. Mechanistic studies showed that Laby A1/A2 exert virolytic activity likely by binding to phosphatidylethanolamine moieties within the viral membrane and by disrupting virus particle membrane integrity. Probably due to its specific mode of action, Laby A1/A2 antiviral activity was not affected by common resistance mutations to known RSV entry inhibitors. Taken together, Laby A1/A2 represent promising candidates for development as RSV inhibitors. Moreover, the cell-based screening system with primary RSV isolates described here should be useful to identify further antiviral agents.
Assuntos
Antivirais/farmacologia , Bacteriocinas/farmacologia , Infecções por Vírus Respiratório Sincicial/tratamento farmacológico , Vírus Sincicial Respiratório Humano/efeitos dos fármacos , Internalização do Vírus/efeitos dos fármacos , Animais , Linhagem Celular , Células Cultivadas , Feminino , Humanos , Pulmão/citologia , Camundongos , Camundongos Endogâmicos BALB C , Vírus Sincicial Respiratório Humano/fisiologiaRESUMO
Infections with enterohemorrhagic Escherichia coli (EHEC) cause disease ranging from mild diarrhea to hemolytic-uremic syndrome (HUS) and are the most common cause of renal failure in children in high-income countries. The severity of the disease derives from the release of Shiga toxins (Stx). The use of antibiotics to treat EHEC infections is generally avoided, as it can result in increased stx expression. Here, we systematically tested different classes of antibiotics and found that their influence on stx expression and release varies significantly. We assessed a selection of these antibiotics in vivo using the Citrobacter rodentium Ïstx2dact mouse model and show that stx2d-inducing antibiotics resulted in weight loss and kidney damage despite clearance of the infection. However, several non-Stx-inducing antibiotics cleared bacterial infection without causing Stx-mediated pathology. Our results suggest that these antibiotics might be useful in the treatment of EHEC-infected human patients and decrease the risk of HUS development.
Assuntos
Injúria Renal Aguda/prevenção & controle , Antibacterianos/uso terapêutico , Escherichia coli Êntero-Hemorrágica/efeitos dos fármacos , Infecções por Escherichia coli/tratamento farmacológico , Toxina Shiga II/metabolismo , Injúria Renal Aguda/microbiologia , Animais , Citrobacter rodentium/genética , Citrobacter rodentium/metabolismo , Modelos Animais de Doenças , Escherichia coli Êntero-Hemorrágica/patogenicidade , Infecções por Escherichia coli/microbiologia , Infecções por Escherichia coli/patologia , Feminino , Síndrome Hemolítico-Urêmica/tratamento farmacológico , Síndrome Hemolítico-Urêmica/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Toxina Shiga II/genética , Toxina Shiga II/toxicidadeRESUMO
Chronic hepatotropic viral infections are characterized by exhausted CD8+ T cells in the presence of cognate antigen in the liver. The impairment of T cell response limits the control of chronic hepatotropic viruses. Immune-modulatory strategies are attractive options to re-invigorate exhausted T cells. However, in hepatotropic viral infections, the knowledge about immune-modulatory effects on the in-situ regulation of exhausted intrahepatic CD8+ T cells is limited. In this study, we elucidated the functional heterogeneity in the pool of exhausted CD8+ T cells in the liver of mice expressing the model antigen Ova in a fraction of hepatocytes. We found a subpopulation of intrahepatic CXCR5+ Ova-specific CD8+ T cells, which are profoundly cytotoxic, exhibiting efficient metabolic functions as well as improved memory recall and self-maintenance. The intrahepatic Ova-specific CXCR5+ CD8+ T cells are possibly tissue resident cells, which may rely largely on OXPHOS and glycolysis to fuel their cellular processes. Importantly, host conditioning with CpG oligonucleotide reinvigorates and promotes exhausted T cell expansion, facilitating complete antigen eradication. The CpG oligonucleotide-mediated reinvigoration may support resident memory T cell formation and the maintenance of CXCR5+ Ova-specific CD8+ T cells in the liver. These findings suggest that CpG oligodinucleotide may preferentially target CXCR5+ CD8+ T cells for expansion to facilitate the revival of exhausted T cells. Thus, therapeutic strategies aiming to expand CXCR5+ CD8+ T cells might provide a novel approach against chronic liver infection.
Assuntos
Antígenos/imunologia , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Imunomodulação , Fígado/imunologia , Fígado/metabolismo , Receptores CXCR5/metabolismo , Transferência Adotiva , Animais , Biomarcadores , Proliferação de Células , Imunização , Fígado/patologia , Ativação Linfocitária/imunologia , Camundongos , Camundongos Transgênicos , Mitocôndrias/imunologia , Mitocôndrias/metabolismo , Especificidade do Receptor de Antígeno de Linfócitos T , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismoRESUMO
Cytomegalovirus (CMV) is a ubiquitous ß-herpesvirus that establishes life-long latent infection in a high percentage of the population worldwide. CMV induces the strongest and most durable CD8+ T cell response known in human clinical medicine. Due to its unique properties, the virus represents a promising candidate vaccine vector for the induction of persistent cellular immunity. To take advantage of this, we constructed a recombinant murine CMV (MCMV) expressing an MHC-I restricted epitope from influenza A virus (IAV) H1N1 within the immediate early 2 (ie2) gene. Only mice that were immunized intranasally (i.n.) were capable of controlling IAV infection, despite the greater potency of the intraperitoneally (i.p.) vaccination in inducing a systemic IAV-specific CD8+ T cell response. The protective capacity of the i.n. immunization was associated with its ability to induce IAV-specific tissue-resident memory CD8+ T (CD8TRM) cells in the lungs. Our data demonstrate that the protective effect exerted by the i.n. immunization was critically mediated by antigen-specific CD8+ T cells. CD8TRM cells promoted the induction of IFNγ and chemokines that facilitate the recruitment of antigen-specific CD8+ T cells to the lungs. Overall, our results showed that locally applied MCMV vectors could induce mucosal immunity at sites of entry, providing superior immune protection against respiratory infections.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Imunidade nas Mucosas , Vacinas contra Influenza/imunologia , Muromegalovirus/imunologia , Administração Intranasal , Sequência de Aminoácidos , Animais , Linhagem Celular , Quimiocinas/biossíntese , Epitopos de Linfócito T/administração & dosagem , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Feminino , Produtos do Gene env/administração & dosagem , Produtos do Gene env/genética , Produtos do Gene env/imunologia , Vetores Genéticos , Humanos , Vírus da Influenza A Subtipo H1N1/genética , Vírus da Influenza A Subtipo H1N1/imunologia , Vacinas contra Influenza/administração & dosagem , Vacinas contra Influenza/genética , Influenza Humana/imunologia , Influenza Humana/prevenção & controle , Pulmão/imunologia , Pulmão/virologia , Camundongos , Camundongos Endogâmicos BALB C , Muromegalovirus/genética , Células NIH 3T3 , Fragmentos de Peptídeos/administração & dosagem , Fragmentos de Peptídeos/genética , Fragmentos de Peptídeos/imunologia , Mucosa Respiratória/imunologia , Mucosa Respiratória/virologia , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologiaRESUMO
Pseudomonas aeruginosa is an environmental microorganism and a causative agent of diverse acute and chronic, biofilm-associated infections. Advancing research-based knowledge on its adaptation to conditions within the human host is bound to reveal novel strategies and targets for therapeutic intervention. Here, we investigated the traits that P. aeruginosa PA14 as well as a virulence attenuated ΔlasR mutant need to survive in selected murine infection models. Experimentally, the genetic programs that the bacteria use to adapt to biofilm-associated versus acute infections were dissected by passaging transposon mutant libraries through mouse lungs (acute) or mouse tumours (biofilm-infection). Adaptive metabolic changes of P. aeruginosa were generally required during both infection processes. Counter-selection against flagella expression was observed during acute lung infections. Obviously, avoidance of flagella-mediated activation of host immunity is advantageous for the wildtype bacteria. For the ΔlasR mutant, loss of flagella did not confer a selective advantage. Apparently, other pathogenesis mechanisms are active in this virulence attenuated strain. In contrast, the infective process of P. aeruginosa in the chronic biofilm model apparently required expression of flagellin. Together, our findings imply that the host immune reactions against the infectious agent are very decisive for acuteness and duration of the infectious disease. They direct disease outcome.
Assuntos
Flagelos/fisiologia , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/fisiologia , Animais , Biofilmes , Doença Crônica , Flagelos/genética , Camundongos , Camundongos Endogâmicos BALB C , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidade , Infecções Respiratórias/microbiologia , VirulênciaRESUMO
The sterilization of potentially infectious animal carcasses is an important biologic safety issue in animal facilities operating as infection or quarantine barriers. However, the literature lacks a validated protocol. Here we describe the validation of an autoclave program suitable for daily use in a small rodent biocontainment unit. We evaluated several procedures for processing mouse carcasses in a standard autoclave. Heat sensors and biologic indicators were implanted inside the peritoneal cavity of dead mice, which were loaded at various densities into IVC cages or metal boxes. Heat sensors revealed broad differences in temperature inside carcasses compared with the autoclave chamber. Achieving the appropriate sterilization temperature was considerably prolonged in carcasses compared with typical laboratory waste material. We show that for 5 cadavers placed well separated inside an IVC, a modified program for mouse cage sterilization using 134 °C for 15 min is suitable. To sterilize approximately 1 kg of carcasses in autoclavable boxes, a period of 6 h is required to reach an effective temperature of 121 °C for 60 min at the center of the waste by using an autoclave program for liquids. In conclusion, we here validated 2 protocols for the sterilization of potentially infectious mouse carcasses, to ensure the application of efficacious procedures.