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2.
BMC Genomics ; 20(1): 99, 2019 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-30704413

RESUMEN

BACKGROUND: Salmonella enterica subsp. diarizonae (IIIb) is frequently isolated from the environment, cold-blooded reptiles, sheep and humans; however only a few studies describe the isolation of this subspecies from invasive human infections. The factors contributing to this unusual behavior are currently unknown. RESULTS: We report here the genome features of two diarizonae strains, SBO13 and SBO27, isolated from endocervical tissue collected post-abortion and from cerebrospinal fluid of a newborn child, respectively, in the city of Santa Cruz, Bolivia. Although isolated six years apart, SBO27 in 2008 and SBO13 in 2014, both strains belong to the same sequence type 1256 (ST1256) and show a high degree of genome conservation sharing more than 99% of their genes, including the conservation of a ~ 10 kb plasmid. A prominent feature of the two genomes is the presence of 24 genomic islands (GIs), in addition to 10 complete Salmonella pathogenicity islands (SPI) and fragments of SPI-7, a pathogenicity island first reported in the human-adapted serovar Typhi. Some of the GIs identified in SBO13 and SBO27 harbor genes putatively encoding auto-transporters involved in adhesion, lipopolysaccharide modifying enzymes, putative toxins, pili-related proteins, efflux pumps, and several putative membrane cation transport related-genes, among others. These two Bolivian isolates also share genes encoding the type-III secretion system effector proteins SseK2, SseK3 and SlrP with other diarizonae sequence types (ST) mainly-associated with infections in humans. The sseK2, sseK3 and slrP genes were either absent or showing frameshift mutations in a significant proportion of genomes from environmental diarizonae isolates. CONCLUSIONS: The comparative genomic study of two diarizonae strains isolated in Bolivia from human patients uncovered the presence of many genes putatively related to virulence. The statistically-significant acquisition of a unique combination of these functions by diarizonae strains isolated from humans may have impacted the ability of these isolates to successfully infect the human host.


Asunto(s)
Genoma Bacteriano , Infecciones por Salmonella/genética , Salmonella enterica/genética , Salmonella enterica/aislamiento & purificación , Factores de Virulencia/genética , Virulencia , Adulto , Femenino , Islas Genómicas , Genómica , Humanos , Recién Nacido , Filogenia , Infecciones por Salmonella/microbiología , Salmonella enterica/patogenicidad , Adulto Joven
3.
Artículo en Inglés | MEDLINE | ID: mdl-31611347

RESUMEN

The rapid emergence of multidrug resistance among bacterial pathogens has become a significant challenge to human health in our century. Therefore, development of next-generation antibacterial compounds is an urgent need. Two-component signal transduction systems (TCS) are stimulus-response coupling devices that allow bacteria to sense and elaborate adaptive responses to changing environmental conditions, including the challenges that pathogenic bacteria face inside the host. The differential presence of TCS, present in bacteria but absent in the animal kingdom, makes them attractive targets in the search for new antibacterial compounds. In Salmonella enterica, the PhoP/PhoQ two-component system controls the expression of crucial phenotypes that define the ability of the pathogen to establish infection in the host. We now report the screening of 686 compounds from a GlaxoSmithKline published kinase inhibitor set in a high-throughput whole-cell assay that targets Salmonella enterica serovar Typhimurium PhoP/PhoQ. We identified a series of quinazoline compounds that showed selective and potent downregulation of PhoP/PhoQ-activated genes and define structural attributes required for their efficacy. We demonstrate that their bioactivity is due to repression of the PhoQ sensor autokinase activity mediated by interaction with its catalytic domain, acting as competitive inhibitors of ATP binding. While noncytotoxic, the hit molecules exhibit antivirulence effect by blockage of S Typhimurium intramacrophage replication. Together, these features make these quinazoline compounds stand out as exciting leads to develop a therapeutic intervention to fight salmonellosis.


Asunto(s)
Quinazolinas/farmacología , Salmonella typhimurium/efectos de los fármacos , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica/genética , Salmonella typhimurium/metabolismo , Transducción de Señal , Relación Estructura-Actividad , Virulencia/genética
4.
Infect Immun ; 86(1)2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-29061704

RESUMEN

Salmonella enterica serovar Dublin is adapted to cattle but is able to infect humans with high invasiveness. An acute inflammatory response at the intestine helps to prevent Salmonella dissemination to systemic sites. Flagella contribute to this response by providing motility and FliC-mediated signaling through pattern recognition receptors. In a previous work, we reported a high frequency (11 out of 25) of S Dublin isolates lacking flagella in a collection obtained from humans and cattle. The aflagellate strains were impaired in their proinflammatory properties in vitro and in vivo The aim of this work was to elucidate the underlying cause of the absence of flagella in S Dublin isolates. We report here that class 3 flagellar genes are repressed in the human aflagellate isolates, due to impaired secretion of FliA anti-sigma factor FlgM. This phenotype is due to an in-frame 42-nucleotide deletion in the fliE gene, which codes for a protein located in the flagellar basal body. The deletion is predicted to produce a protein lacking amino acids 18 to 31. The aflagellate phenotype was highly stable; revertants were obtained only when fliA was artificially overexpressed combined with several successive passages in motility agar. DNA sequence analysis revealed that motile revertants resulted from duplications of DNA sequences in fliE adjacent to the deleted region. These duplications produced a FliE protein of similar length to the wild type and demonstrate that amino acids 18 to 31 of FliE are not essential. The same deletion was detected in S Dublin isolates obtained from cattle, indicating that this mutation circulates in nature.


Asunto(s)
Proteínas Bacterianas/genética , Flagelos/genética , Salmonella enterica/genética , Eliminación de Secuencia/genética , Secuencia de Aminoácidos , Aminoácidos , Animales , Cuerpos Basales/metabolismo , Secuencia de Bases , Bovinos , Femenino , Genes Duplicados/genética , Humanos , Inflamación/microbiología , Ratones , Ratones Endogámicos C57BL , Fenotipo , Salmonelosis Animal/microbiología , Alineación de Secuencia , Factor sigma/genética
5.
Proc Natl Acad Sci U S A ; 112(3): 863-8, 2015 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-25535353

RESUMEN

Many bacterial pathogens are specialized, infecting one or few hosts, and this is often associated with more acute disease presentation. Specific genomes show markers of this specialization, which often reflect a balance between gene acquisition and functional gene loss. Within Salmonella enterica subspecies enterica, a single lineage exists that includes human and animal pathogens adapted to cause infection in different hosts, including S. enterica serovar Enteritidis (multiple hosts), S. Gallinarum (birds), and S. Dublin (cattle). This provides an excellent evolutionary context in which differences between these pathogen genomes can be related to host range. Genome sequences were obtained from ∼ 60 isolates selected to represent the known diversity of this lineage. Examination and comparison of the clades within the phylogeny of this lineage revealed signs of host restriction as well as evolutionary events that mark a path to host generalism. We have identified the nature and order of events for both evolutionary trajectories. The impact of functional gene loss was predicted based upon position within metabolic pathways and confirmed with phenotyping assays. The structure of S. Enteritidis is more complex than previously known, as a second clade of S. Enteritidis was revealed that is distinct from those commonly seen to cause disease in humans or animals, and that is more closely related to S. Gallinarum. Isolates from this second clade were tested in a chick model of infection and exhibited a reduced colonization phenotype, which we postulate represents an intermediate stage in pathogen-host adaptation.


Asunto(s)
Adaptación Fisiológica , Evolución Molecular , Genoma Bacteriano , Salmonella/genética , Cromosomas Bacterianos , Seudogenes
6.
Infect Immun ; 85(2)2017 02.
Artículo en Inglés | MEDLINE | ID: mdl-27872237

RESUMEN

Signaling through Toll-like receptors (TLRs), the main receptors in innate immunity, is essential for the defense of mucosal surfaces. It was previously shown that systemic TLR5 stimulation by bacterial flagellin induces an immediate, transient interleukin-22 (IL-22)-dependent antimicrobial response to bacterial or viral infections of the mucosa. This process was dependent on the activation of type 3 innate lymphoid cells (ILCs). The objective of the present study was to analyze the effects of flagellin treatment in a murine model of oral infection with Yersinia pseudotuberculosis (an invasive, Gram-negative, enteropathogenic bacterium that targets the small intestine). We found that systemic administration of flagellin significantly increased the survival rate after intestinal infection (but not systemic infection) by Y. pseudotuberculosis This protection was associated with a low bacterial count in the gut and the spleen. In contrast, no protection was afforded by administration of the TLR4 agonist lipopolysaccharide, suggesting the presence of a flagellin-specific effect. Lastly, we found that TLR5- and MyD88-mediated signaling was required for the protective effects of flagellin, whereas neither lymphoid cells nor IL-22 was involved.


Asunto(s)
Flagelina/inmunología , Interleucinas/metabolismo , Mucosa Intestinal/inmunología , Mucosa Intestinal/metabolismo , Infecciones por Yersinia pseudotuberculosis/inmunología , Infecciones por Yersinia pseudotuberculosis/metabolismo , Yersinia pseudotuberculosis/inmunología , Animales , Modelos Animales de Enfermedad , Femenino , Flagelina/administración & dosificación , Interleucinas/genética , Mucosa Intestinal/microbiología , Lipopolisacáridos/inmunología , Ratones , Ratones Noqueados , Proteínas Recombinantes de Fusión , Transducción de Señal , Receptores Toll-Like/metabolismo , Infecciones por Yersinia pseudotuberculosis/microbiología , Infecciones por Yersinia pseudotuberculosis/mortalidad , Interleucina-22
7.
J Transl Med ; 14(1): 323, 2016 11 22.
Artículo en Inglés | MEDLINE | ID: mdl-27876058

RESUMEN

BACKGROUND: Non-Hodgkin lymphomas (NHL) are the most frequent hemato-oncological malignancies. Despite recent major advances in treatment, a substantial proportion of patients relapses highlighting the need for new therapeutic modalities. Promissory results obtained in pre-clinical studies are usually not translated when moving into clinical trials. Pre-clinical studies are mainly conducted in animals with high tumor burden; instead patients undergo chemotherapy as first line of treatment and most likely are under remission when immunotherapies are applied. Thus, an animal model that more closely resembles patients' conditions would be a valuable tool. METHODS: BALB/c mice were injected subcutaneously with A20 lymphoma cells and after tumor development different doses of chemotherapy were assessed to find optimal conditions for minimal residual disease (MRD) establishment. Tumor growth and survival, as well as drugs side effects, were all evaluated. Complete lymphoma remission was monitored in vivo using positron emission tomography (PET), and the results were correlated with histology. Immunological status was assessed by splenocytes proliferation assays in NHL-complete remission mice and by analyzing tumor cell infiltrates and chemokines/cytokines gene expression in the tumor microenvironment of animals with residual lymphoma. RESULTS: Two cycles of CHOP chemotherapy at days 25 and 35 post-tumor implantation induced complete remission for around 20 days. PET showed to be a suitable follow-up technique for MRD condition with 85.7 and 75% of sensibility and specificity respectively. Proliferative responses upon mitogen stimulation were similar in animals that received chemotherapy and wild type mice. Tumors from animals with residual lymphoma showed higher numbers of CD4+ and CD8+ and similar numbers of NK, neutrophils and Tregs infiltrating cells as compared with non-treated animals. Gene expression of several cytokines as well as an array of chemokines associated with migration of activated T cells to tumor sites was upregulated in the tumor microenvironment of animals that received chemotherapy treatment. CONCLUSIONS: We established a NHL-B pre-clinical model using standard chemotherapy to achieve MRD in immunocompetent animals. The MRD condition is maintained for approximately 20 days providing a therapeutic window of time where new immunotherapies can be tested in conditions closer to the clinics.


Asunto(s)
Linfoma no Hodgkin/patología , Animales , Antineoplásicos/efectos adversos , Antineoplásicos/farmacología , Antineoplásicos/uso terapéutico , Protocolos de Quimioterapia Combinada Antineoplásica/efectos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Proliferación Celular , Quimiocinas/genética , Quimiocinas/metabolismo , Modelos Animales de Enfermedad , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Linfoma no Hodgkin/tratamiento farmacológico , Linfoma no Hodgkin/genética , Linfoma no Hodgkin/inmunología , Ratones Endogámicos BALB C , Neoplasia Residual/tratamiento farmacológico , Neoplasia Residual/patología , Tomografía Computarizada por Tomografía de Emisión de Positrones , Estándares de Referencia , Inducción de Remisión , Bazo/patología , Análisis de Supervivencia , Resultado del Tratamiento
8.
Antimicrob Agents Chemother ; 59(10): 6064-72, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26195519

RESUMEN

Prophylactic intranasal administration of the Toll-like receptor 5 (TLR5) agonist flagellin protects mice against respiratory pathogenic bacteria. We hypothesized that TLR5-mediated stimulation of lung immunity might improve the therapeutic index of antibiotics for the treatment of Streptococcus pneumoniae respiratory infections in mice. Intranasal administration of flagellin was combined with either oral administration of amoxicillin or intraperitoneal injection of trimethoprim-sulfamethoxazole to treat S. pneumoniae-infected animals. Compared with standalone treatments, the combination of antibiotic and flagellin resulted in a lower bacterial load in the lungs and greater protection against S. pneumoniae dissemination and was associated with an early increase in neutrophil infiltration in the airways. The antibiotic-flagellin combination treatment was, however, not associated with any exacerbation of inflammation. Moreover, combination treatment was more efficacious than standalone antibiotic treatments in the context of post-influenza virus pneumococcal infection. Lastly, TLR5 signaling was shown to be mandatory for the efficacy of the combined antibacterial therapy. This report is the first to show that combining antibiotic treatment with the stimulation of mucosal innate immunity is a potent antibacterial strategy against pneumonia.


Asunto(s)
Antibacterianos/uso terapéutico , Flagelina/uso terapéutico , Infecciones Neumocócicas/tratamiento farmacológico , Receptor Toll-Like 5/agonistas , Combinación Trimetoprim y Sulfametoxazol/uso terapéutico , Amoxicilina/uso terapéutico , Animales , Femenino , Inmunidad Innata/efectos de los fármacos , Ratones , Ratones Endogámicos BALB C , Infiltración Neutrófila/efectos de los fármacos , Streptococcus pneumoniae/efectos de los fármacos , Streptococcus pneumoniae/patogenicidad
9.
BMC Cancer ; 15: 620, 2015 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-26347489

RESUMEN

BACKGROUND: Metastatic breast cancer is a major cause of death among women worldwide; therefore efficient therapeutic strategies are extremely needed. In this work we have developed a gene therapy- and bacteria-based combined neoadjuvant approach and evaluated its antitumor effect in a clinically relevant animal model of metastatic breast cancer. METHODS: 2×10(8) particles of a Semliki Forest virus vector expressing interleukin-12 (SFV-IL-12) and/or 2×10(7) units of an aroC (-) Samonella Typhimurium strain (LVR01) were injected into 4T1 tumor nodules orthotopically implanted in mice. Tumors were surgically resected and long-term survival was determined. IL-12 and interferon-γ were quantified by Enzyme-Linked ImmunoSorbent Assay, bacteria was visualized by inmunohistochemistry and the number of lung metastasis was calculated with a clonogenic assay. RESULTS: SFV-IL-12 and LVR01 timely inoculated and followed by surgical resection of tumors succeeded in complete inhibition of lethal lung metastasis and long-term survival in 90% of treated mice. The combined therapy was markedly synergistic compared to each treatment alone, since SFV-IL-12 monotherapy showed a potent antiangiogenic effect, being able to inhibit tumor growth and extend survival, but could not prevent establishment of distant metastasis and death of tumor-excised animals. On the other hand, LVR01 alone also showed a significant, although limited, antitumor potential, despite its ability to invade breast cancer cells and induce granulocyte recruitment. The efficacy of the combined therapy depended on the order in which both factors were administered; inasmuch the therapeutic effect was only observed when SFV-IL-12 was administered previous to LVR01, whereas administration of LVR01 before SFV-IL-12 had negligible antitumor activity. Moreover, pre-treatment with LVR01 seemed to suppress SFV-IL-12 antiangiogenic effects associated to lower IL-12 expression in this group. Re-challenged mice were unable to reject a second 4T1 tumor; however 100% of them could be totally cured by applying the same neoadjuvant combined regimen. To our knowledge, these are the most encouraging results obtained to date in a post-operatory setting using the highly aggressive 4T1 animal model. CONCLUSIONS: SFV-IL-12-based gene therapy combined with Salmonella LVR01 neoadjuvant administration has a synergic antitumor effect and may be a promising therapeutic option to prevent and/or eradicate pre-operatory metastasis in locally advanced breast cancer.


Asunto(s)
Neoplasias de la Mama/terapia , Regulación de la Expresión Génica/fisiología , Terapia Genética , Interleucina-12/genética , Neoplasias Pulmonares/terapia , Salmonella typhimurium/genética , Virus de los Bosques Semliki/genética , Animales , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Línea Celular Tumoral , Terapia Combinada , Ensayo de Inmunoadsorción Enzimática , Femenino , Vectores Genéticos , Inmunocompetencia , Inmunohistoquímica , Interferón gamma/sangre , Interleucina-12/sangre , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/secundario , Ratones , Ratones Endogámicos BALB C , Terapia Neoadyuvante , Trasplante de Neoplasias , Fragmentos de Péptidos/sangre , Tasa de Supervivencia
10.
J Infect Dis ; 210(3): 493-503, 2014 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-24577508

RESUMEN

Mucosal sites are continuously exposed to pathogenic microorganisms and are therefore equipped to control respiratory infections. Type 3 innate lymphoid cells (ILC3) are key players in antimicrobial defense in intestinal mucosa, through interleukin 17 and interleukin 22 (IL-22) production. The present study aimed at analyzing the distribution and function of ILC3 in the respiratory tract. We first observed that lung mucosa harbors a discrete population of ILC3 expressing CD127, CD90, CCR6, and the transcriptional factor RORγt. In addition, lung ILC3 were identified as a major source of IL-22 in response to interleukin 23 stimulation. During Streptococcus pneumoniae infection, ILC3 rapidly accumulated in the lung tissue to produce IL-22. In response to S. pneumoniae, dendritic cells and MyD88, an important adaptor of innate immunity, play critical functions in IL-22 production by ILC3. Finally, administration of the Toll-like receptor 5 agonist flagellin during S. pneumoniae challenge exacerbated IL-22 production by ILC3, a process that protects against lethal infection. In conclusion, boosting lung ILC3 might represent an interesting strategy to fight respiratory bacterial infections.


Asunto(s)
Interleucinas/metabolismo , Pulmón/metabolismo , Linfocitos/clasificación , Linfocitos/fisiología , Neumonía Neumocócica/inmunología , Neumonía Neumocócica/metabolismo , Animales , Femenino , Interleucina-17/genética , Interleucina-17/metabolismo , Interleucinas/genética , Activación de Linfocitos , Ratones , Ratones Noqueados , Streptococcus pneumoniae , Interleucina-22
11.
Immunology ; 143(3): 428-37, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-24834964

RESUMEN

Despite the efficacy of current immune-chemotherapy for treatment of B-cell non-Hodgkin lymphoma, a substantial proportion of patients relapse, highlighting the need for new therapeutic modalities. The use of live microorganisms to develop anti-tumoural therapies has evolved since Coley's toxin and is now receiving renewed attention. Salmonella Typhimurium has been shown to be highly effective as an anti-tumour agent in many solid cancer models, but it has not been used in haemato-oncology. Here, we report that intra-tumoural administration of LVR01 (attenuated S. Typhimurium strain with safety profile) elicits local and systemic anti-tumour immunity, resulting in extended survival in a lymphoma model. LVR01 induces intra-tumoural recruitment of neutrophils and activated CD8(+) T cells, as well as increasing the natural killer cell activation status. Furthermore, a systemic specific anti-tumour response with a clear T helper type 1 profile was observed. This approach is an alternative therapeutic strategy for lymphoma patients that could be easily moved into clinical trials.


Asunto(s)
Inmunoterapia/métodos , Linfoma de Células B/inmunología , Salmonella typhimurium/inmunología , Animales , Muerte Celular/inmunología , Línea Celular Tumoral , Modelos Animales de Enfermedad , Epítopos/inmunología , Femenino , Inmunidad Humoral , Interferón gamma/genética , Interferón gamma/metabolismo , Leucocitos/inmunología , Leucocitos/patología , Linfoma de Células B/genética , Linfoma de Células B/metabolismo , Linfoma de Células B/mortalidad , Linfoma de Células B/patología , Linfoma de Células B/terapia , Ratones , Bazo/citología , Bazo/inmunología , Bazo/microbiología
12.
Antimicrob Agents Chemother ; 58(11): 6528-35, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25136026

RESUMEN

Antibiotic resistance, especially due to ß-lactamases, has become one of the main obstacles in the correct treatment of Salmonella infections; furthermore, antibiotic resistance determines a gain of function that may encompass a biological cost, or fitness reduction, to the resistant bacteria. The aim of this work was to determine in vitro if the production of the class B ß-lactamase VIM-2 determined a fitness cost for Salmonella enterica serovar Typhimurium. To that end the gene blaVIM-2 was cloned into the virulent strain S. Typhimurium SL1344, using both the tightly regulated pBAD22 vector and the natural plasmid pST12, for inducible and constitutive expression, respectively. Fitness studies were performed by means of motility, growth rate, invasiveness in epithelial cells, and plasmid stability. The expression of blaVIM-2 was accompanied by alterations in micro- and macroscopic morphology and reduced growth rate and motility, as well as diminished invasiveness in epithelial cells. These results suggest that VIM-2 production entails a substantial fitness cost for S. Typhimurium, which in turn may account for the extremely low number of reports of metallo-ß-lactamase-producing Salmonella spp.


Asunto(s)
Farmacorresistencia Bacteriana Múltiple/genética , Aptitud Genética/genética , Infecciones por Salmonella/tratamiento farmacológico , Salmonella typhimurium/patogenicidad , beta-Lactamasas/genética , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Células CACO-2 , Línea Celular , Clonación Molecular , Células Epiteliales/microbiología , Humanos , Pruebas de Sensibilidad Microbiana , Plásmidos/efectos de los fármacos , Plásmidos/genética , Infecciones por Salmonella/microbiología , Salmonella typhimurium/efectos de los fármacos , Salmonella typhimurium/genética , beta-Lactamasas/biosíntesis
13.
Antonie Van Leeuwenhoek ; 105(6): 1139-48, 2014 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-24771125

RESUMEN

Proteus mirabilis expresses several virulence factors including MR/P fimbriae and flagella. Bacterial flagellin has frequently shown interesting adjuvant and protective properties in vaccine formulations. However, native P. mirabilis flagellin has not been analyzed so far. Native P. mirabilis flagellin was evaluated as a protective antigen and as an adjuvant in co-immunizations with MrpA (structural subunit of MR/P fimbriae) using an ascending UTI model in the mouse. Four groups of mice were intranasally treated with either MrpA, native flagellin, both proteins and PBS. Urine and blood samples were collected before and after immunization for specific antibodies determination. Cytokine production was assessed in immunized mice splenocytes cultures. Mice were challenged with P. mirabilis, and bacteria quantified in kidneys and bladders. MrpA immunization induced serum and urine specific anti-MrpA antibodies while MrpA coadministered with native flagellin did not. None of the animals developed significant anti-flagellin antibodies. Only MrpA-immunized mice showed a significant decrease of P. mirabilis in bladders and kidneys. Instead, infection levels in MrpA-flagellin or flagellin-treated mice showed no significant differences with the control group. IL-10 was significantly induced in splenocytes of mice that received native flagellin or MrpA-flagellin. Native P. mirabilis flagellin did not protect mice against an ascending UTI. Moreover, it showed an immunomodulatory effect, neutralizing the protective role of MrpA. P. mirabilis flagellin exhibits particular immunological properties compared to other bacterial flagellins.


Asunto(s)
Antígenos Bacterianos/inmunología , Proteínas Bacterianas/inmunología , Vacunas Bacterianas/inmunología , Flagelina/inmunología , Infecciones por Proteus/prevención & control , Proteus mirabilis/inmunología , Infecciones Urinarias/prevención & control , Adyuvantes Inmunológicos/administración & dosificación , Animales , Anticuerpos Antibacterianos/sangre , Anticuerpos Antibacterianos/orina , Antígenos Bacterianos/administración & dosificación , Proteínas Bacterianas/administración & dosificación , Vacunas Bacterianas/administración & dosificación , Modelos Animales de Enfermedad , Antagonismo de Drogas , Flagelina/administración & dosificación , Interleucina-10/biosíntesis , Riñón/microbiología , Leucocitos Mononucleares/inmunología , Ratones , Infecciones por Proteus/inmunología , Proteus mirabilis/crecimiento & desarrollo , Vejiga Urinaria/microbiología , Infecciones Urinarias/inmunología
14.
Vaccines (Basel) ; 12(8)2024 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-39204028

RESUMEN

Increasing the effectiveness of vaccines against respiratory viruses is particularly relevant for the elderly, since they are prone to develop serious infections due to comorbidities and the senescence of the immune system. The addition of saponin-based adjuvants is an interesting strategy to increase the effectiveness of vaccines. We have previously shown that ISCOM matrices from Q. brasiliensis (IMXQB) are a safe and potent adjuvant. In this study, we evaluated the use of IMXQB as an adjuvant for the seasonal trivalent influenza vaccine (TIV) in an aged mice model. Herein, we show that subcutaneous injection of the adjuvanted vaccine promoted higher titers of IgM, IgG (and isotypes), and serum hemagglutination inhibition titers (HAI). Notably, aged mice immunized by intranasal route also produced higher IgG (and isotypes) and IgA titers up to 120 days after priming, as well as demonstrating an improvement in the HAI antibodies against the TIV. Further, experimental infected aged mice treated once with sera from adult naïve mice previously immunized with TIV-IMXQB subcutaneously successfully controlled the infection. Overall, TIV-IMXQB improved the immunogenicity compared to TIV by enhancing systemic and mucosal immunity in old mice conferring a faster recovery after the H1N1pdm09-like virus challenge. Thus, IMXQB nanoparticles may be a promising platform for next-generation viral vaccines.

15.
Sci Rep ; 14(1): 5148, 2024 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-38429351

RESUMEN

Colistin remains one of the last-resort therapies for combating infections caused by multidrug-resistant (MDR) Enterobacterales, despite its adverse nephro- and neuro-toxic effects. This study elucidates the mechanism of action of a non-antibiotic 4-anilinoquinazoline-based compound that synergistically enhances the effectiveness of colistin against Salmonella enterica. The quinazoline sensitizes Salmonella by deactivating intrinsic, mutational, and transferable resistance mechanisms that enable Salmonella to counteract the antibiotic impact colistin, together with an induced disruption to the electrochemical balance of the bacterial membrane. The attenuation of colistin resistance via the combined treatment approach also proves efficacious against E. coli, Klebsiella, and Acinetobacter strains. The dual therapy reduces the mortality of Galleria mellonella larvae undergoing a systemic Salmonella infection when compared to individual drug treatments. Overall, our findings unveil the potential of the quinazoline-colistin combined therapy as an innovative strategy against MDR bacteria.


Asunto(s)
Mariposas Nocturnas , Infecciones por Salmonella , Animales , Colistina/farmacología , Colistina/uso terapéutico , Escherichia coli , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Farmacorresistencia Bacteriana Múltiple , Infecciones por Salmonella/tratamiento farmacológico , Pruebas de Sensibilidad Microbiana
16.
Cell Rep ; 43(3): 113932, 2024 Mar 26.
Artículo en Inglés | MEDLINE | ID: mdl-38457336

RESUMEN

Innate immune cells can undergo long-term functional reprogramming after certain infections, a process called trained immunity (TI). Here, we focus on antigens of Leishmania braziliensis, which induced anti-tumor effects via trained immunity in human monocytes. We reveal that monocytes exposed to promastigote antigens of L. braziliensis develop an enhanced response to subsequent exposure to Toll-like receptor (TLR)2 or TLR4 ligands. Mechanistically, the induction of TI in monocytes by L. braziliensis is mediated by multiple pattern recognition receptors, changes in metabolism, and increased deposition of H3K4me3 at the promoter regions of immune genes. The administration of L. braziliensis exerts potent anti-tumor capabilities by delaying tumor growth and prolonging survival of mice with non-Hodgkin lymphoma. Our work reveals mechanisms of TI induced by L. braziliensis in vitro and identifies its potential for cancer immunotherapy.


Asunto(s)
Leishmania braziliensis , Leishmaniasis Cutánea , Neoplasias , Humanos , Ratones , Animales , Monocitos
17.
Oncology ; 84(4): 200-9, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23328435

RESUMEN

INTRODUCTION: Vascular endothelial growth factor (VEGF) is one of the classic factors to tumor-induced angiogenesis in several tumor types, including melanoma. Bevacizumab, a monoclonal antibody against VEGF, could be used as an imaging tool in preclinical studies. OBJECTIVE: To radiolabel bevacizumab with [(99m)Tc(CO)3(OH2)3](+) and evaluate it in vivo and in vitro for melanoma imaging properties. METHODS: Bevacizumab was radiolabeled with [(99m)Tc(CO)3(OH2)3](+) ion in saline. The radiochemical stability of the labeled antibody was assessed. The biodistribution and scintigraphy imaging of the radiolabeled antibody were evaluated in normal C57BL/6J mice and in C57BL/6J mice bearing murine B16F1 melanoma tumors. Immunoreactivity of bevacizumab to murine tumors was determined from direct immunofluorescence and immunoblotting assays. RESULTS: We demonstrate that (99m)Tc(CO)3-bevacizumab was stable. In vivo biodistribution studies revealed that tumor uptake of (99m)Tc(CO)3-bevacizumab was 2.64 and 2.51 %ID/g at 4 and 24 h postinjection. Scintigraphy image studies showed tumor selective uptake of (99m)Tc(CO)3-bevacizumab in the tumor-bearing mice. This affinity was confirmed by immunoassays performed on B16F10 tumor samples. CONCLUSIONS: (99m)Tc(CO)3-bevacizumab could be used as an approach for tumor nuclear imaging in preclinical studies. This should be useful to provide insights into the angiogenic stimulus before and after chemotherapy, which might help improve current antitumor therapy.


Asunto(s)
Anticuerpos Monoclonales Humanizados , Melanoma Experimental/diagnóstico por imagen , Compuestos de Organotecnecio , Radiofármacos , Tecnecio , Animales , Anticuerpos Monoclonales Humanizados/química , Anticuerpos Monoclonales Humanizados/inmunología , Anticuerpos Monoclonales Humanizados/farmacocinética , Bevacizumab , Marcaje Isotópico/métodos , Ratones , Ratones Endogámicos C57BL , Cintigrafía , Radiofármacos/farmacocinética , Tecnecio/farmacocinética , Distribución Tisular , Microambiente Tumoral/inmunología , Factor A de Crecimiento Endotelial Vascular/inmunología
18.
J Infect Dis ; 206(5): 723-34, 2012 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-22723642

RESUMEN

BACKGROUND: Exogenous activation of pulmonary invariant natural killer T (iNKT) cells, a population of lipid-reactive αß T lymphocytes, with use of mucosal α-galactosylceramide (α-GalCer) administration, is a promising approach to control respiratory bacterial infections. We undertook the present study to characterize mechanisms leading to α-GalCer-mediated protection against lethal infection with Streptococcus pneumoniae serotype 1, a major respiratory pathogen in humans. METHODS AND RESULTS: α-GalCer was administered by the intranasal route before infection with S. pneumoniae. We showed that respiratory dendritic cells (DCs), most likely the CD103(+) subset, play a major role in the activation (IFN-γ and IL-17 release) of pulmonary iNKT cells, whereas alveolar and interstitial macrophages are minor players. After challenge, S. pneumoniae was rapidly (4 hours) eliminated in the alveolar spaces, a phenomenon that depended on respiratory DCs and neutrophils, but not macrophages, and on the early production of both IFN-γ and IL-17. Protection was also associated with the synthesis of various interferon-dependent and IL-17-associated genes as revealed by transcriptomic analysis. CONCLUSIONS: These data imply a new function for pulmonary CD103(+) DCs in mucosal activation of iNKT cells and establish a critical role for both IFN-γ and IL-17 signalling pathways in mediating the innate immune response to S. pneumoniae.


Asunto(s)
Células Dendríticas/inmunología , Galactosilceramidas/farmacología , Células T Asesinas Naturales/inmunología , Infecciones Neumocócicas/inmunología , Streptococcus pneumoniae/inmunología , Animales , Antígenos CD/inmunología , Líquido del Lavado Bronquioalveolar/microbiología , Células Dendríticas/microbiología , Galactosilceramidas/uso terapéutico , Inmunidad Innata/inmunología , Cadenas alfa de Integrinas/inmunología , Interferón gamma/inmunología , Interleucina-17/inmunología , Estimación de Kaplan-Meier , Masculino , Ratones , Ratones Endogámicos C57BL , Células T Asesinas Naturales/microbiología , Infecciones Neumocócicas/microbiología , Transducción de Señal
19.
Front Immunol ; 14: 1163858, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37197659

RESUMEN

The threat of viral influenza infections has sparked research efforts to develop vaccines that can induce broadly protective immunity with safe adjuvants that trigger robust immune responses. Here, we demonstrate that subcutaneous or intranasal delivery of a seasonal trivalent influenza vaccine (TIV) adjuvanted with the Quillaja brasiliensis saponin-based nanoparticle (IMXQB) increases the potency of TIV. The adjuvanted vaccine (TIV-IMXQB) elicited high levels of IgG2a and IgG1 antibodies with virus-neutralizing capacity and improved serum hemagglutination inhibition titers. The cellular immune response induced by TIV-IMXQB suggests the presence of a mixed Th1/Th2 cytokine profile, antibody-secreting cells (ASCs) skewed toward an IgG2a phenotype, a positive delayed-type hypersensitivity (DTH) response, and effector CD4+ and CD8+ T cells. After challenge, viral titers in the lungs were significantly lower in animals receiving TIV-IMXQB than in those inoculated with TIV alone. Most notably, mice vaccinated intranasally with TIV-IMXQB and challenged with a lethal dose of influenza virus were fully protected against weight loss and lung virus replication, with no mortality, whereas, among animals vaccinated with TIV alone, the mortality rate was 75%. These findings demonstrate that TIV-IMXQB improved the immune responses to TIV, and, unlike the commercial vaccine, conferred full protection against influenza challenge.


Asunto(s)
Vacunas contra la Influenza , Gripe Humana , Nanopartículas , Animales , Ratones , Humanos , Gripe Humana/prevención & control , Quillaja , Linfocitos T CD8-positivos , Adyuvantes Inmunológicos , Adyuvantes Farmacéuticos , Saponinas de Quillaja , Inmunoglobulina G
20.
Antimicrob Agents Chemother ; 56(4): 2132-4, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22290976

RESUMEN

We studied a clinical isolate of Salmonella enterica serotype Enteritidis showing resistance to oxyiminocephalosporins. PCR analysis confirmed the presence of bla(CTX-M-14) linked to IS903 in a 95-kb IncI1 conjugative plasmid. Such a plasmid is maintained on account of the presence of a pndAC addiction system. Multilocus sequence typing (MLST) analysis indicated that the strain belongs to ST11. This is the first report of bla(CTX-M-14) in Salmonella Enteritidis of human origin in South America.


Asunto(s)
Infecciones por Salmonella/microbiología , Salmonella enteritidis/efectos de los fármacos , Salmonella enteritidis/genética , beta-Lactamasas/genética , Anciano , Antibacterianos/farmacología , Resistencia a las Cefalosporinas/genética , Conjugación Genética , Femenino , Humanos , Fallo Renal Crónico/complicaciones , Pruebas de Sensibilidad Microbiana , Plásmidos/genética , Reacción en Cadena de la Polimerasa , América del Sur , Uruguay
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