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1.
Proc Natl Acad Sci U S A ; 115(41): 10416-10421, 2018 10 09.
Artículo en Inglés | MEDLINE | ID: mdl-30254173

RESUMEN

While CD4 Th1 cells are required for resistance to intramacrophage infections, adoptive transfer of Th1 cells is insufficient to protect against Salmonella infection. Using an epitope-tagged vaccine strain of Salmonella, we found that effective protection correlated with expanded Salmonella-specific memory CD4 T cells in circulation and nonlymphoid tissues. However, naive mice that previously shared a blood supply with vaccinated partners lacked T cell memory with characteristics of tissue residence and did not acquire robust protective immunity. Using a YFP-IFN-γ reporter system, we identified Th1 cells in the liver of immunized mice that displayed markers of tissue residence, including P2X7, ARTC2, LFA-1, and CD101. Adoptive transfer of liver memory cells after ARTC2 blockade increased protection against highly virulent bacteria. Taken together, these data demonstrate that noncirculating memory Th1 cells are a vital component of immunity to Salmonella infection and should be the focus of vaccine strategies.


Asunto(s)
Memoria Inmunológica/inmunología , Hígado/inmunología , Infecciones por Salmonella/inmunología , Salmonella typhimurium/inmunología , Linfocitos T/inmunología , Células TH1/inmunología , Animales , Células Cultivadas , Femenino , Inmunización , Hígado/microbiología , Ratones , Ratones Endogámicos C57BL , Infecciones por Salmonella/microbiología , Infecciones por Salmonella/prevención & control , Linfocitos T/microbiología , Células TH1/microbiología
2.
Infect Immun ; 87(11)2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31427450

RESUMEN

Salmonella infection can cause gastroenteritis in healthy individuals or a serious, systemic infection in immunocompromised patients and has a global impact. CD4 Th1 cells represent the main lymphocyte population that participates in bacterial clearance during both primary and secondary infections in mice of the H-2b haplotype. Previous studies have used congenic mice to examine the function of major histocompatibility complex (MHC) molecules in elimination of this pathogen from the host. In this study, we further characterized the ability of H-2b, H-2k, and H-2u molecules to influence adaptive immunity to Salmonella in MHC congenic mice. By depleting different cell populations during infection, we unexpectedly found that CD8 T cells, in addition to CD4 T cells, play a major role in accelerated clearance of bacteria from H-2k congenic hosts. Our data suggest that CD8 T cells accelerate clearance in some MHC congenic mouse strains and could therefore represent an unexpected contributor to the protective efficacy of Salmonella vaccines outside the typical studies in C57BL/6 mice.


Asunto(s)
Linfocitos T CD8-positivos/fisiología , Salmonelosis Animal/inmunología , Salmonelosis Animal/microbiología , Salmonella typhimurium/inmunología , Animales , Linfocitos T CD4-Positivos/metabolismo , Infecciones por Chlamydia/inmunología , Infecciones por Chlamydia/microbiología , Chlamydia muridarum , Haplotipos , Interferón gamma , Complejo Mayor de Histocompatibilidad/genética , Ratones
3.
Infect Immun ; 84(10): 2833-41, 2016 10.
Artículo en Inglés | MEDLINE | ID: mdl-27456828

RESUMEN

Salmonella infection profoundly affects host erythroid development, but the mechanisms responsible for this effect remain poorly understood. We monitored the impact of Salmonella infection on erythroid development and found that systemic infection induced anemia, splenomegaly, elevated erythropoietin (EPO) levels, and extramedullary erythropoiesis in a process independent of Salmonella pathogenicity island 2 (SPI2) or flagellin. The circulating EPO level was also constitutively higher in mice lacking the expression of signal-regulatory protein α (SIRPα). The expression level of EPO mRNA was elevated in the kidney and liver but not increased in the spleens of infected mice despite the presence of extramedullary erythropoiesis in this tissue. In contrast to data from a previous report, mice lacking EPO receptor (EPOR) expression on nonerythroid cells (EPOR rescued) had bacterial loads similar to those of wild-type mice following Salmonella infection. Indeed, treatment to reduce splenic erythroblasts and mature red blood cells correlated with elevated bacterial burdens, implying that extramedullary erythropoiesis benefits the host. Together, these findings emphasize the profound effect of Salmonella infection on erythroid development and suggest that the modulation of erythroid development has both positive and negative consequences for host immunity.


Asunto(s)
Eritropoyetina/metabolismo , Riñón/metabolismo , Hígado/metabolismo , Infecciones por Salmonella/metabolismo , Infecciones por Salmonella/microbiología , Salmonella typhi , Anemia/sangre , Animales , Carga Bacteriana , Modelos Animales de Enfermedad , Eritropoyesis/fisiología , Citometría de Flujo , Ratones , Ratones Endogámicos C57BL , ARN Mensajero/metabolismo , Receptores de Eritropoyetina/metabolismo , Receptores Inmunológicos/metabolismo , Bazo/metabolismo
4.
mBio ; 11(6)2020 12 22.
Artículo en Inglés | MEDLINE | ID: mdl-33443133

RESUMEN

The Helicobacter pylori type IV secretion system (T4SS) encoded on the cag pathogenicity island (cagPAI) secretes the CagA oncoprotein and other effectors into the gastric epithelium. During murine infection, T4SS function is lost in an immune-dependent manner, typically as a result of in-frame recombination in the middle repeat region of cagY, though single nucleotide polymorphisms (SNPs) in cagY or in other essential genes may also occur. Loss of T4SS function also occurs in gerbils, nonhuman primates, and humans, suggesting that it is biologically relevant and not simply an artifact of the murine model. Here, we sought to identify physiologically relevant conditions under which T4SS function is maintained in the murine model. We found that loss of H. pylori T4SS function in mice was blunted by systemic Salmonella coinfection and completely eliminated by dietary iron restriction. Both have epidemiologic parallels in humans, since H. pylori strains from individuals in developing countries, where iron deficiency and systemic infections are common, are also more often cagPAI+ than strains from developed countries. These results have implications for our fundamental understanding of the cagPAI and also provide experimental tools that permit the study of T4SS function in the murine model.IMPORTANCE The type IV secretion system (T4SS) is the major Helicobacter pylori virulence factor, though its function is lost during murine infection. Loss of function also occurs in gerbils and in humans, suggesting that it is biologically relevant, but the conditions under which T4SS regulation occurs are unknown. Here, we found that systemic coinfection with Salmonella and iron deprivation each promote retention of T4SS function. These results improve our understanding of the cag pathogenicity island (cagPAI) and provide experimental tools that permit the study of T4SS function in the murine model.


Asunto(s)
Antígenos Bacterianos/genética , Proteínas Bacterianas/genética , Islas Genómicas , Infecciones por Helicobacter/microbiología , Helicobacter pylori/genética , Sistemas de Secreción Tipo IV/genética , Animales , Coinfección/microbiología , Femenino , Mucosa Gástrica , Helicobacter pylori/metabolismo , Helicobacter pylori/patogenicidad , Hierro/metabolismo , Ratones , Ratones Endogámicos C57BL , Salmonelosis Animal/sangre , Salmonelosis Animal/microbiología , Sistemas de Secreción Tipo IV/metabolismo , Factores de Virulencia
6.
mBio ; 7(6)2016 12 20.
Artículo en Inglés | MEDLINE | ID: mdl-27999159

RESUMEN

Antibiotic intervention is an effective treatment strategy for many bacterial infections and liberates bacterial antigens and stimulatory products that can induce an inflammatory response. Despite the opportunity for bacterial killing to enhance the development of adaptive immunity, patients treated successfully with antibiotics can suffer from reinfection. Studies in mouse models of Salmonella and Chlamydia infection also demonstrate that early antibiotic intervention reduces host protective immunity to subsequent infection. This heightened susceptibility to reinfection correlates with poor development of Th1 and antibody responses in antibiotic-treated mice but can be overcome by delayed antibiotic intervention, thus suggesting a requirement for sustained T cell stimulation for protection. Although the contribution of memory T cell subsets is imperfectly understood in both of these infection models, a protective role for noncirculating memory cells is suggested by recent studies. Together, these data propose a model where antibiotic treatment specifically interrupts tissue-resident memory T cell formation. Greater understanding of the mechanistic basis of this phenomenon might suggest therapeutic interventions to restore a protective memory response in antibiotic-treated patients, thus reducing the incidence of reinfection.


Asunto(s)
Antibacterianos/efectos adversos , Susceptibilidad a Enfermedades/inmunología , Memoria Inmunológica/efectos de los fármacos , Animales , Antibacterianos/uso terapéutico , Formación de Anticuerpos , Infecciones por Chlamydia/tratamiento farmacológico , Infecciones por Chlamydia/inmunología , Infecciones por Chlamydia/prevención & control , Modelos Animales de Enfermedad , Susceptibilidad a Enfermedades/etiología , Esquema de Medicación , Humanos , Ratones , Recurrencia , Infecciones por Salmonella/tratamiento farmacológico , Infecciones por Salmonella/inmunología , Infecciones por Salmonella/prevención & control , Células TH1/inmunología
7.
Future Microbiol ; 10(10): 1615-27, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26439708

RESUMEN

AIM: In most infectious disease models, it is assumed that gavage needle infection is the most reliable means of pathogen delivery to the GI tract. However, this methodology can cause esophageal tearing and induces stress in experimental animals, both of which have the potential to impact early infection and the subsequent immune response. MATERIALS & METHODS: C57BL/6 mice were orally infected with virulent Salmonella Typhimurium SL1344 either by intragastric gavage preceded by sodium bicarbonate, or by contamination of drinking water. RESULTS: We demonstrate that water contamination delivery of Salmonella is equivalent to gavage inoculation in providing a consistent model of infection. Furthermore, exposure of mice to contaminated drinking water for as little as 4 h allowed maximal mucosal and systemic infection, suggesting an abbreviated window exists for natural intestinal entry. CONCLUSION: Together, these data question the need for gavage delivery for infection with oral pathogens.


Asunto(s)
Agua Potable/microbiología , Salmonelosis Animal/microbiología , Salmonella typhimurium/crecimiento & desarrollo , Microbiología del Agua , Animales , Modelos Animales de Enfermedad , Femenino , Mucosa Intestinal/microbiología , Ratones , Ratones Endogámicos C57BL , Contaminación del Agua
8.
Adv Biol Chem ; 5(7)2015.
Artículo en Inglés | MEDLINE | ID: mdl-27092291

RESUMEN

During Nucleotide Excision Repair (NER) in the yeast S. cerevisiae, ubiquitylation of Rad4 is carried out by the E3 ubiquitin ligase that includes Rad7-Elc1-Cul3 and is critical to optimal NER. Rad7 E3 activity targets Rad4 for degradation by the proteaseome but, in principle, could also trigger other DNA damage responses. We observed increased nuclear ubiquitin foci (Ub-RFP) formation in S. cerevisiae containing a Rad7 E3 ligase mutant (rad7SOCS) in response to DNA damage by benzo[a]pyrenediolepoxide (BPDE) in dividing cells. Immunoblots reveal that ubiquitin conjugates of Rpn10 and Dsk2 accumulate in greater abundance in rad7SOCS compared to RAD7 in dividing cells in response to BPDE which makes Rpn10 and Dsk2 candidates for being the ubiquitylated species observed in our microscopy experiments. Microscopy analysis with strains containing Dsk2-GFP shows that Dsk2-GFP and Dsk2-GFP/Ub-RFP colocalized in nuclear foci form to an increased extent in a rad7SOCS mutant background in dividing cells than in a RAD7 wild-type strain. Further, Dsk2-GFP in the rad7SOCS strain formed more foci at the plasma membrane following BPDE treatment in dividing cells relative to strains containing RAD7 or a rad7Δ deletion mutant. In response to a different agent, UV irradiation, levels of ubiquitylated proteins were increased in rad7SOCS relative to RAD7, and the proteasomal deubiquitylase subunit, Rpn11 was even monoubiquitylated in the absence of damaging agents. Together these data show that Rad7 E3 activity attenuates ubiquitylation of proteins regulating the shuttling of polyubiquitylated proteins to the proteasome (Dsk2 and Rpn10) and removal of ubiquitin chains just prior to degradation (Rpn11). Since Rad7 E3 ligase activity has been shown to increase ubiquitylation of its target proteins, yet our results show increased ubiquitylation in the absence of Rad7 E3, we suggest that Rad7 E3 action regulates ubiquitin ligase and deubiquitylase (DUB) activities that act on Rpn10, Dsk2 and Rpn11.

9.
Acta Histochem ; 113(4): 409-15, 2011 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-20546858

RESUMEN

Rad14 is a DNA damage recognition protein in yeast Nucleotide Excision Repair (NER) and believed to function early in the cascade of events. The function of Rad14 presumably precedes that of the Rad1-Rad10 endonuclease complex, which functions in a downstream step incising DNA 5' to the site of DNA damage. We investigated whether recruitment of Rad10 to UV-induced DNA damage sites in live cells is dependent on Rad14 using fluorescence microscopy. Experiments were carried out using Saccharomyces cerevisiae strains in which the gene for Rad14 was fused to Cyan Fluorescent Protein (Rad14-CFP) and that of Rad10 was fused to Yellow Fluorescent Protein (Rad10-YFP). Rad14-CFP forms nuclear localized CFP fluorescent foci in response to UV irradiation with the peak induction occurring 15min post-irradiation. In contrast, Rad10-YFP foci form in response to UV with the peak induction occurring 2h post-irradiation. Recruitment of Rad14-CFP is not dependent on the RAD10 gene but Rad10-YFP is recruited to UV-induced YFP foci in a RAD14-dependent fashion. Time-lapse experiments indicate that Rad14-CFP foci are transient, typically persisting less than 6min. Together these data support the model that yeast NER protein assembly is step-wise whereas Rad14 required to recruit Rad10 and Rad14 involvement is transient.


Asunto(s)
Enzimas Reparadoras del ADN/genética , Reparación del ADN , ADN de Hongos/genética , Proteínas de Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae , Endonucleasas Específicas del ADN y ARN con un Solo Filamento/genética , Proteínas Bacterianas , Daño del ADN/efectos de la radiación , Enzimas Reparadoras del ADN/metabolismo , ADN de Hongos/efectos de la radiación , Proteínas Fluorescentes Verdes , Proteínas Luminiscentes , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/efectos de la radiación , Proteínas de Saccharomyces cerevisiae/metabolismo , Endonucleasas Específicas del ADN y ARN con un Solo Filamento/metabolismo , Rayos Ultravioleta
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