scholarly journals Enhanced Susceptibility to Citrobacter rodentium Infection in MicroRNA-155-Deficient Mice

2012 ◽  
Vol 81 (3) ◽  
pp. 723-732 ◽  
Author(s):  
Simon Clare ◽  
Victoria John ◽  
Alan W. Walker ◽  
Jennifer L. Hill ◽  
Cei Abreu-Goodger ◽  
...  
Keyword(s):  
Immune Responses ◽  
Bacterial Pathogen ◽  
Citrobacter Rodentium ◽  
Wild Type ◽  
Content Type ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Control Gene Expression ◽  
Gastrointestinal Tissue ◽  
Deficient Mice

ABSTRACTMicroRNAs (miRNAs) are small noncoding molecules that control gene expression posttranscriptionally, with microRNA-155 (miR-155) one of the first to be implicated in immune regulation. Here, we show that miR-155-deficient mice are less able to eradicate a mucosalCitrobacter rodentiuminfection than wild-type C57BL/6 mice. miR-155-deficient mice exhibited prolonged colonization associated with a higherC. rodentiumburden in gastrointestinal tissue and spread into systemic tissues. Germinal center formation and humoral immune responses againstC. rodentiumwere severely impaired in infected miR-155-deficient mice. A similarly susceptible phenotype was observed in μMT mice reconstituted with miR-155-deficient B cells, indicating that miR-155 is required intrinsically for mediating protection against this predominantly luminal bacterial pathogen.

scholarly journals Correlates of Immune Protection following Cutaneous Immunization with an Attenuated Burkholderia pseudomallei Vaccine

2013 ◽  
Vol 81 (12) ◽  
pp. 4626-4634 ◽  
Author(s):  
Ediane B. Silva ◽  
Andrew Goodyear ◽  
Marjorie D. Sutherland ◽  
Nicole L. Podnecky ◽  
Mercedes Gonzalez-Juarrero ◽  
...  
Keyword(s):  
Immune Responses ◽  
Vaccine Strain ◽  
Protective Immunity ◽  
Burkholderia Pseudomallei ◽  
Partial Protection ◽  
Content Type ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Immune Correlates ◽  
Draining Lymph Nodes

ABSTRACTInfections with the Gram-negative bacteriumBurkholderia pseudomallei(melioidosis) are associated with high mortality, and there is currently no approved vaccine to prevent the development of melioidosis in humans. Infected patients also do not develop protective immunity to reinfection, and some individuals will develop chronic, subclinical infections withB. pseudomallei. At present, our understanding of what constitutes effective protective immunity againstB. pseudomalleiinfection remains incomplete. Therefore, we conducted a study to elucidate immune correlates of vaccine-induced protective immunity against acuteB. pseudomalleiinfection. BALB/c and C57BL/6 mice were immunized subcutaneously with a highly attenuated, Select Agent-excludedpurMdeletion mutant ofB. pseudomallei(strain Bp82) and then subjected to intranasal challenge with virulentB. pseudomalleistrain 1026b. Immunization with Bp82 generated significant protection from challenge withB. pseudomallei, and protection was associated with a significant reduction in bacterial burden in lungs, liver, and spleen of immunized mice. Humoral immunity was critically important for vaccine-induced protection, as mice lacking B cells were not protected by immunization and serum from Bp82-vaccinated mice could transfer partial protection to nonvaccinated animals. In contrast, vaccine-induced protective immunity was found to be independent of both CD4 and CD8 T cells. Tracking studies demonstrated uptake of the Bp82 vaccine strain predominately by neutrophils in vaccine-draining lymph nodes and by smaller numbers of dendritic cells (DC) and monocytes. We concluded that protection following cutaneous immunization with a live attenuatedBurkholderiavaccine strain was dependent primarily on generation of effective humoral immune responses.

scholarly journals Humoral Immune Responses in a Human Case of Glanders

2012 ◽  
Vol 19 (5) ◽  
pp. 814-816 ◽  
Author(s):  
David M. Waag ◽  
Marilyn J. England ◽  
David DeShazer
Keyword(s):  
Immune Responses ◽  
Burkholderia Pseudomallei ◽  
Human Case ◽  
Burkholderia Mallei ◽  
Baseline Serum ◽  
Content Type ◽  
Whole Cells ◽  
Humoral Immune ◽  
Diagnostic Antigen ◽  
Humoral Immune Responses

ABSTRACTWithin 2 months of acquiring glanders, a patient developed 8-, 16-, and 4-fold increases, respectively, in specific IgA, IgG, and IgM serological titers againstBurkholderia mallei. Within 14 months of infection, the titers decreased to the baseline. Serum from this patient was also highly reactive againstBurkholderia pseudomalleiwhole cells.Burkholderia malleiwhole cells did not react with sera from patients with other diseases. Therefore, an assay using aB. malleicellular diagnostic antigen may be useful for the serodiagnosis of glanders.

scholarly journals Distinct Contributions of Interleukin-1α (IL-1α) and IL-1β to Innate Immune Recognition of Pseudomonas aeruginosa in the Lung

2014 ◽  
Vol 82 (10) ◽  
pp. 4204-4211 ◽  
Author(s):  
Khatoun Al Moussawi ◽  
Barbara I. Kazmierczak
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Immune Responses ◽  
Bacterial Pathogen ◽  
Innate Immune ◽  
Immune Recognition ◽  
Content Type ◽  
Caspase 1 ◽  
Rapid Responses ◽  
Subsequent Activation ◽  
Deficient Mice

ABSTRACTThe bacterial pathogenPseudomonas aeruginosacauses acute infections associated with significant morbidity and mortality.P. aeruginosaelicits strong innate immune responses in immunocompetent hosts, and the resulting recruitment of neutrophils to the site of infection is necessary for bacterial clearance.P. aeruginosalipopolysaccharide and flagellin are recognized by extracellular Toll-like receptors, but the most rapid responses to infection occur when cytosolic receptors sense flagellin or type 3 secretion system (T3SS) structural proteins. The subsequent activation of the NLRC4 inflammasome and caspase-1 generates an interleukin-1β (IL-1β) signal that is required for the rapid neutrophilic response. A T3SS effector, exotoxin U (ExoU), can inhibit activation of the NLRC4 inflammasome and caspase-1. Thus, our observation that IL-1 receptor (IL-1R)-mediated signals were still required to initiate a response to ExoU-producing bacteria was unexpected. As both IL-1α and IL-1β signal via the IL-1R, we examined immune responses in mice lacking either of these cytokines. IL-1β-deficient mice responded to ExoU-producingP. aeruginosabacteria similarly to wild-type animals; however, IL-1α-deficient mice had an attenuated immune response. The situation was reversed following infections by ExoU-negative bacteria: here, IL-1α was dispensable for neutrophil recruitment, while IL-1β was required. IL-1α secretion by macrophages infected with ExoU-producingP. aeruginosaisolates was independent of both caspase-1 and caspase-11. This study documents distinct roles for IL-1α and IL-1β in the response toP. aeruginosainfection as a function of the T3SS effectors produced by the infecting strain. The redundancy of these two cytokines nonetheless allows the infected host to mount a response to ExoU-positive and -negative bacterial isolates.

scholarly journals Yersinia pestis caf1 Variants and the Limits of Plague Vaccine Protection

2008 ◽  
Vol 76 (5) ◽  
pp. 2025-2036 ◽  
Author(s):  
Lauriane E. Quenee ◽  
Claire A. Cornelius ◽  
Nancy A. Ciletti ◽  
Derek Elli ◽  
Olaf Schneewind
Keyword(s):  
Immune Responses ◽  
Yersinia Pestis ◽  
Protective Immunity ◽  
Wild Type ◽  
Vaccine Protection ◽  
Subunit Vaccines ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Plague Vaccine ◽  
Highly Virulent

ABSTRACT Yersinia pestis, the highly virulent agent of plague, is a biological weapon. Strategies that prevent plague have been sought for centuries, and immunization with live, attenuated (nonpigmented) strains or subunit vaccines with F1 (Caf1) antigen is considered effective. We show here that immunization with live, attenuated strains generates plague-protective immunity and humoral immune responses against F1 pilus antigen and LcrV. Y. pestis variants lacking caf1 (F1 pili) are not only fully virulent in animal models of bubonic and pneumonic plague but also break through immune responses generated with live, attenuated strains or F1 subunit vaccines. In contrast, immunization with purified LcrV, a protein at the tip of type III needles, generates protective immunity against the wild-type and the fully virulent caf1 mutant strain, in agreement with the notion that LcrV can elicit vaccine protection against both types of virulent plague strains.

scholarly journals Altered Humoral Immune Responses and IgG Subtypes in NOX2-Deficient Mice and Patients: A Key Role for NOX2 in Antigen-Presenting Cells

2018 ◽  
Vol 9 ◽  
Author(s):  
Julien Cachat ◽  
Christine Deffert ◽  
Marco Alessandrini ◽  
Pascale Roux-Lombard ◽  
Audrey Le Gouellec ◽  
...  
Keyword(s):  
Immune Responses ◽  
Antigen Presenting Cells ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Antigen Presenting ◽  
Deficient Mice

scholarly journals CD40L-deficient mice show deficits in antiviral immunity and have an impaired memory CD8+ CTL response.

1996 ◽  
Vol 183 (5) ◽  
pp. 2129-2142 ◽  
Author(s):  
P Borrow ◽  
A Tishon ◽  
S Lee ◽  
J Xu ◽  
I S Grewal ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Humoral Immunity ◽  
Cd4 T Cells ◽  
Antiviral Immunity ◽  
Ctl Response ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Deficient Mice

The ligand for CD40 (CD40L) is expressed on the surface of activated CD4+ T cells and its role in T-B cell collaborations and thymus-dependent humoral immunity is well established. Recently, by generating CD40L-knockout mice, we have confirmed its previously described role in humoral immunity and defined another important function of this molecule in the in vivo clonal expansion of antigen-specific CD4+ T cells. Here, we investigated the potential in vivo role of CD40L in antiviral immunity by examining the immune response mounted by CD40L-deficient mice following infection with lymphocytic choriomeningitis virus (LCMV), Pichinde virus, or vesicular stomatitis virus. Humoral immune responses of CD40L-deficient mice to these viruses were severely compromised, although moderate titres of antiviral IgM and some IgG2a were produced by virus-infected CD40L-deficient mice by a CD4+ T cell-independent mechanism. By contrast, CD40L-deficient mice made strong primary CTL responses to all three viruses. Interestingly however, although memory CTL activity was detectable in CD40L-deficient mice two months after infection with LCMV, the memory CTL response was much less efficient than in wild-type mice. Together, the results show that CD40-CD40L interactions are required for strong antiviral humoral immune responses, and reveal a novel role for CD40L in the establishment and/or maintenance of CD8+ CTL memory.

scholarly journals Recombinant Vesicular Stomatitis Virus Vectors Expressing Herpes Simplex Virus Type 2 gD Elicit Robust CD4+ Th1 Immune Responses and Are Protective in Mouse and Guinea Pig Models of Vaginal Challenge

2006 ◽  
Vol 80 (9) ◽  
pp. 4447-4457 ◽  
Author(s):  
Robert J. Natuk ◽  
David Cooper ◽  
Min Guo ◽  
Priscilla Calderon ◽  
Kevin J. Wright ◽  
...  
Keyword(s):  
Herpes Simplex ◽  
Immune Responses ◽  
Vesicular Stomatitis Virus ◽  
Guinea Pigs ◽  
Wild Type ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Vesicular Stomatitis ◽  
Simplex Virus

ABSTRACT Recombinant vesicular stomatitis virus (rVSV) vectors offer an attractive approach for the induction of robust cellular and humoral immune responses directed against human pathogen target antigens. We evaluated rVSV vectors expressing full-length glycoprotein D (gD) from herpes simplex virus type 2 (HSV-2) in mice and guinea pigs for immunogenicity and protective efficacy against genital challenge with wild-type HSV-2. Robust Th1-polarized anti-gD immune responses were demonstrated in the murine model as measured by induction of gD-specific cytotoxic T lymphocytes and increased gamma interferon expression. The isotype makeup of the serum anti-gD immunoglobulin G (IgG) response was consistent with the presence of a Th1-CD4+ anti-gD response, characterized by a high IgG2a/IgG1 IgG subclass ratio. Functional anti-HSV-2 neutralizing serum antibody responses were readily demonstrated in both guinea pigs and mice that had been immunized with rVSV-gD vaccines. Furthermore, guinea pigs and mice were prophylactically protected from genital challenge with high doses of wild-type HSV-2. In addition, guinea pigs were highly protected against the establishment of latent infection as evidenced by low or absent HSV-2 genome copies in dorsal root ganglia after virus challenge. In summary, rVSV-gD vectors were successfully used to elicit potent anti-gD Th1-like cellular and humoral immune responses that were protective against HSV-2 disease in guinea pigs and mice.

scholarly journals Live Oral Typhoid Vaccine Ty21a Induces Cross-Reactive Humoral Immune Responses against Salmonella enterica Serovar Paratyphi A andS. Paratyphi B in Humans

2012 ◽  
Vol 19 (6) ◽  
pp. 825-834 ◽  
Author(s):  
Rezwanul Wahid ◽  
Raphael Simon ◽  
Shah J. Zafar ◽  
Myron M. Levine ◽  
Marcelo B. Sztein
Keyword(s):  
Immune Responses ◽  
Salmonella Enterica ◽  
Outer Membrane Proteins ◽  
Serum Antibody ◽  
Significant Proportion ◽  
Field Trials ◽  
Content Type ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Paratyphi B

ABSTRACTEnteric fever caused bySalmonella entericaserovar Paratyphi A infection has emerged as an important public health problem. Recognizing that in randomized controlled field trials oral immunization with attenuatedS. entericaserovar Typhi live vaccine Ty21a conferred significant cross-protection againstS. Paratyphi B but notS. Paratyphi A disease, we undertook a clinical study to ascertain whether humoral immune responses could explain the field trial results. Ty21a immunization of adult residents of Maryland elicited predominantly IgA antibody-secreting cells (ASC) that recognizeS. Typhi lipopolysaccharide (LPS). Cross-reactivity toS. Paratyphi A LPS was significantly lower than that toS. Paratyphi B LPS. ASC producing IgG and IgA that bind LPS from each of theseSalmonellaserovars expressed CD27 and integrin α4β7 (gut homing), with a significant proportion coexpressing CD62L (secondary lymphoid tissue homing). No significant differences were observed in serum antibody against LPS of the different serovars. Levels of IgA B memory (BM) cells toS. Typhi LPS were significantly higher than those againstS. Paratyphi A or B LPS, with no differences observed betweenS. Paratyphi A and B. The response of IgA BMto outer membrane proteins (OMP) fromS. Typhi was significantly stronger than that to OMP ofS. Paratyphi A but similar to that to OMP ofS. Paratyphi B. The percentages of IgG or IgA BMresponders to LPS or OMP from theseSalmonellastrains were similar. Whereas cross-reactive humoral immune responses toS. Paratyphi A or B antigens are demonstrable following Ty21a immunization, they cannot explain the efficacy data gleaned from controlled field trials.

scholarly journals Impact of Malaria Preexposure on Antiparasite Cellular and Humoral Immune Responses after Controlled Human Malaria Infection

2015 ◽  
Vol 83 (5) ◽  
pp. 2185-2196 ◽  
Author(s):  
Joshua M. Obiero ◽  
Seif Shekalaghe ◽  
Cornelus C. Hermsen ◽  
Maxmillian Mpina ◽  
Else M. Bijker ◽  
...  
Keyword(s):  
Immune Responses ◽  
Intradermal Injection ◽  
Content Type ◽  
Human Malaria ◽  
Humoral Immune ◽  
Humoral Immune Responses ◽  
Controlled Human Malaria Infection ◽  
Circulating Lymphocytes ◽  
Ifn Γ

To understand the effect of previous malaria exposure on antiparasite immune responses is important for developing successful immunization strategies. Controlled human malaria infections (CHMIs) using cryopreservedPlasmodium falciparumsporozoites provide a unique opportunity to study differences in acquisition or recall of antimalaria immune responses in individuals from different transmission settings and genetic backgrounds. In this study, we compared antiparasite humoral and cellular immune responses in two cohorts of malaria-naive Dutch volunteers and Tanzanians from an area of low malarial endemicity, who were subjected to the identical CHMI protocol by intradermal injection ofP. falciparumsporozoites. Samples from both trials were analyzed in parallel in a single center to ensure direct comparability of immunological outcomes. Within the Tanzanian cohort, we distinguished one group with moderate levels of preexisting antibodies to asexualP. falciparumlysate and another that, based onP. falciparumserology, resembled the malaria-naive Dutch cohort. PositiveP. falciparumserology at baseline was associated with a lower parasite density at first detection by quantitative PCR (qPCR) after CHMI than that for Tanzanian volunteers with negative serology. Post-CHMI, both Tanzanian groups showed a stronger increase in anti-P. falciparumantibody titers than Dutch volunteers, indicating similar levels of B-cell memory independent of serology. In contrast to the Dutch, Tanzanians failed to increaseP. falciparum-specificin vitrorecall gamma interferon (IFN-γ) production after CHMI, and innate IFN-γ responses were lower inP. falciparumlysate-seropositive individuals than in seronegative individuals. In conclusion, positiveP. falciparumlysate serology can be used to identify individuals with better parasite control but weaker IFN-γ responses in circulating lymphocytes, which may help to stratify volunteers in future CHMI trials in areas where malaria is endemic.

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