scholarly journals Messing with the Sentinels—The Interaction of Staphylococcus aureus with Dendritic Cells

2018 ◽  
Vol 6 (3) ◽  
pp. 87 ◽  
Author(s):  
Murthy Darisipudi ◽  
Maria Nordengrün ◽  
Barbara Bröker ◽  
Vincent Péton

Staphylococcus aureus (S. aureus) is a dangerous pathogen as well as a frequent colonizer, threatening human health worldwide. Protection against S. aureus infection is challenging, as the bacteria have sophisticated strategies to escape the host immune response. To maintain equilibrium with S. aureus, both innate and adaptive immune effector mechanisms are required. Dendritic cells (DCs) are critical players at the interface between the two arms of the immune system, indispensable for inducing specific T cell responses. In this review, we highlight the importance of DCs in mounting innate as well as adaptive immune responses against S. aureus with emphasis on their role in S. aureus-induced respiratory diseases. We also review what is known about mechanisms that S. aureus has adopted to evade DCs or manipulate these cells to its advantage.

Genes ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 323 ◽  
Author(s):  
Guoying Wang ◽  
Xianghui Li ◽  
Lei Zhang ◽  
Abualgasim Elgaili Abdalla ◽  
Tieshan Teng ◽  
...  

Dendritic cells (DCs) play a critical role in the immune system which sense pathogens and present their antigens to prime the adaptive immune responses. As the progression of sepsis occurs, DCs are capable of orchestrating the aberrant innate immune response by sustaining the Th1/Th2 responses that are essential for host survival. Hence, an in-depth understanding of the characteristics of DCs would have a beneficial effect in overcoming the obstacle occurring in sepsis. This paper focuses on the role of DCs in the progression of sepsis and we also discuss the reverse sepsis-induced immunosuppression through manipulating the DC function. In addition, we highlight some potent immunotherapies that could be used as a novel strategy in the early treatment of sepsis.


2021 ◽  
Vol 12 ◽  
Author(s):  
Loïc Vivien Bocard ◽  
Andrew Robert Kick ◽  
Corinne Hug ◽  
Heidi Erika Lisa Lischer ◽  
Tobias Käser ◽  
...  

This study was initiated to better understand the nature of innate immune responses and the relatively weak and delayed immune response against porcine reproductive and respiratory syndrome virus (PRRSV). Following modified live virus (MLV) vaccination or infection with two PRRSV-2 strains, we analyzed the transcriptome of peripheral blood mononuclear cells collected before and at three and seven days after vaccination or infection. We used blood transcriptional modules (BTMs)-based gene set enrichment analyses. BTMs related to innate immune processes were upregulated by PRRSV-2 strains but downregulated by MLV. In contrast, BTMs related to adaptive immune responses, in particular T cells and cell cycle, were downregulated by PRRSV-2 but upregulated by MLV. In addition, we found differences between the PRRSV strains. Only the more virulent strain induced a strong platelet activation, dendritic cell activation, interferon type I and plasma cell responses. We also calculated the correlations of BTM with the neutralizing antibody and the T-cell responses. Early downregulation (day 0–3) of dendritic cell and B-cell BTM correlated to both CD4 and CD8 T-cell responses. Furthermore, a late (day 3–7) upregulation of interferon type I modules strongly correlated to helper and regulatory T-cell responses, while inflammatory BTM upregulation correlated more to CD8 T-cell responses. BTM related to T cells had positive correlations at three days but negative associations at seven days post-infection. Taken together, this work contributes to resolve the complexity of the innate and adaptive immune responses against PRRSV and indicates a fundamentally different immune response to the less immunogenic MLV compared to field strains which induced robust adaptive immune responses. The identified correlates of T-cell responses will facilitate a rational approach to improve the immunogenicity of MLV.


2020 ◽  
Author(s):  
Stine SF Nielsen ◽  
Line K Vibholm ◽  
Ida Monrad ◽  
Rikke Olesen ◽  
Giacomo S Frattari ◽  
...  

AbstractThe SARS-CoV-2 pandemic currently prevails worldwide. To understand the immunological signature of SARS-CoV-2 infections and aid the search for treatments and vaccines, comprehensive characterization of adaptive immune responses towards SARS-CoV-2 is needed. We investigated the breadth and potency of antibody-, and T-cell immune responses, in 203 recovered SARS-CoV-2 infected patients who presented with asymptomatic to severe infections. We report very broad serological profiles with cross-reactivity to other human coronaviruses. Further, >99% had SARS-CoV-2 epitope specific antibodies, with SARS-CoV-2 neutralization and spike-ACE2 receptor interaction blocking observed in 95% of individuals. A significant positive correlation between spike-ACE2 blocking antibody titers and neutralization potency was observed. SARS-CoV-2 specific CD8+ T-cell responses were clear and quantifiable in 90% of HLA-A2+ individuals. The viral surface spike protein was identified as the dominant target for both neutralizing antibodies and CD8+ T cell responses. Overall, the majority of patients had robust adaptive immune responses, regardless of disease severity.Author summarySARS-CoV-2 can cause severe and deadly infections. However, the immunological understanding of this viral infection is limited. Currently, several vaccines are being developed to help limit transmission and prevent the current pandemic. However, basic understanding of the adaptive immune response developed during SARS-CoV-2 infections is needed to inform further vaccine development and to understand the protective properties of the developed immune response. We investigated, the adaptive immune response developed during SARS-CoV-2 infections in recovered patients experiencing a full spectrum of disease severity, from asymptomatic infections to severe cases requiring hospitalization. We used a novel multiplex serological platform, cell-based neutralization assays and dextramer flow cytometry assays to characterize a broad and robust humoral and cellular immune response towards SARS-CoV-2. We found that the vast majority of recovered individuals have clear detectable and functional SARS-CoV-2 spike specific adaptive immune responses, despite diverse disease severities. The detection of both a humoral and cellular functional spike specific immune response in the vast majority of the individuals, irrespective of asymptomatic manifestations, supports vaccine designs currently underway, and encourages further exploration of whether primary infections provide protection to reinfection.


2021 ◽  
Vol 4 (2) ◽  
pp. 8011-8019
Author(s):  
Giovanna Ganem Favero ◽  
Isabela Lopes Martin ◽  
Fernanda Pereira da Silva Albino ◽  
Carlos Eduardo Fontana ◽  
Sérgio Luiz Pinheiro ◽  
...  

Leptin is a hormone synthesized predominantly by white adipose tissue. Its production levels are directly proportional to the total mass of this tissue in an individual’s body. Apart from its classic role in the regulation of hunger and satiety, it also plays an important part in scenarios involving innate and adaptive immune responses. It has been discovered that leptin levels are altered in a variety of inflammatory responses, such as periodontitis, a condition which derives from a persistent inflammatory immune response from a host facing bacterial infection. The initial trigger for this reaction is the recognition of the pathogens by antigen presenting cells, such as macrophages and dendritic cells, whose actions can be influenced by leptin. This review aims to present the relationship between leptin, dendritic cells and macrophages in the context of periodontal disease. Thus, we have assembled the most important findings related to leptin’s role in the modulation of the immune response carried out by these cells in periodontitis.


2017 ◽  
Vol 27 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Rituparna Chakraborty ◽  
Janin Chandra ◽  
Shuai Cui ◽  
Lynn Tolley ◽  
Matthew A. Cooper ◽  
...  

mBio ◽  
2014 ◽  
Vol 5 (3) ◽  
Author(s):  
Clara Maria Ausiello ◽  
Antonio Cassone

ABSTRACTThe resurgence of pertussis (whooping cough) in countries with high vaccination coverage is alarming and invites reconsideration of the use of current acellular pertussis (aP) vaccines, which have largely replaced the old, reactogenic, whole-cell pertussis (wP) vaccine. Some drawbacks of these vaccines in terms of limited antigenic composition and early waning of antibody levels could be anticipated by the results of in-trial or postlicensure human investigations of B- and T-cell responses in aP versus wP vaccine recipients or unvaccinated, infected children. Recent data in experimental models, including primates, suggest that generation of vaccines capable of a potent, though regulated, stimulation of innate immunity driving effective, persistent adaptive immune responses againstBordetella pertussisinfection should be privileged. Adjuvants that skew Th1/Th17 responses or new wP (detoxified or attenuated) vaccines should be explored. Nonetheless, the high merits of the current aP vaccines in persuading people to resume vaccination against pertussis should not be forgotten.


Viruses ◽  
2009 ◽  
Vol 1 (3) ◽  
pp. 1022-1034 ◽  
Author(s):  
Artur Summerfield ◽  
Kenneth McCullough

2021 ◽  
Author(s):  
Raymond T. Suhandynata ◽  
Nicholas J. Bevins ◽  
Jenny T. Tran ◽  
Deli Huang ◽  
Melissa A. Hoffman ◽  
...  

AbstractBackgroundThe severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has infected over 110 million individuals and led to 2.5 million deaths worldwide. As more individuals are vaccinated, the clinical performance and utility of SARS-CoV-2 serology platforms needs to be evaluated.MethodsThe ability of four commercial SARS-CoV-2 serology platforms to detect previous infection or vaccination were evaluated using a cohort of 53 SARS-CoV-2 PCR-positive patients, 89 SARS-CoV-2-vaccinated healthcare workers (Pfizer or Moderna), and 127 SARS-CoV-2 negative patients. Serology results were compared to a cell based SARS-CoV-2 pseudovirus (PSV) neutralizing antibodies assay.ResultsThe Roche S-(spike) antibody and Diazyme neutralizing antibodies (NAbs) assays detected adaptive immune response in 100.0% and 90.1% of vaccinated individuals who received two-doses of vaccine (initial and booster), respectively. The Roche N-(nucleocapsid) antibody assay and Diazyme IgG assay did not detect adaptive immune response in vaccinated individuals. The Diazyme Nabs assay correlated with the PSV SARS-CoV-2 ID50 neutralization titers (R2= 0.70), while correlation of the Roche S-antibody assay was weaker (R2= 0.39). Median PSV SARS-CoV-2 ID50 titers more than doubled in vaccinated individuals who received two-doses of the Moderna vaccine (ID50: 597) compared to individuals that received a single dose (ID50: 284).ConclusionsThe Roche S-antibody and Diazyme NAbs assays robustly detected adaptive immune responses in SARS-CoV-2 vaccinated individuals and SARS-CoV-2 infected individuals. The Diazyme NAbs assay strongly correlates with the PSV SARS-CoV-2 NAbs in vaccinated individuals. Understanding the reactivity of commercially available serology platforms is important when distinguishing vaccination response versus natural infection.SummaryThe Roche S (spike protein)-antibody and Diazyme neutralizing-antibodies (NAbs) assays were evaluated for their clinical utility in the detection of SARS-CoV-2 related adaptive immune responses by testing SARS-CoV-2 PCR-confirmed patients, SARS-CoV-2-vaccinated individuals, and SARS-CoV-2-negative individuals. Commercial serology results were compared to results generated using a cell-based SARS-CoV-2 pseudovirus (PSV) NAbs assay and previously validated SARS-CoV-2 commercial serology assays (Roche N (nucleocapsid protein) antibody and Diazyme IgG). We demonstrate that the Roche S-antibody and Diazyme NAbs assays detected adaptive immune response in SARS-CoV-2 vaccinated individuals and the presence of SARS-CoV-2 PSV NAbs. The Roche S-antibody assay had an observed positive percent agreement (PPA) of 100% for individuals who received two doses of the Pfizer or Moderna vaccine. By contrast, the Roche N assay and Diazyme IgG assay did not detect vaccine adaptive immune responses. Our findings also indicate that the Diazyme NAbs assay correlates strongly with the levels of SARS-CoV-2 ID50 neutralization titers using the PSV Nab assay in vaccinated individuals.


2020 ◽  
pp. 325-336
Author(s):  
Paul Klenerman

The adaptive immune response is distinguished from the innate immune response by two main features: its capacity to respond flexibly to new, previously unencountered antigens (antigenic specificity), and its enhanced capacity to respond to previously encountered antigens (immunological memory). These two features have provided the focus for much research attention, from the time of Jenner, through Pasteur onwards. Historically, innate and adaptive immune responses have often been treated as separate, with the latter being considered more ‘advanced’ because of its flexibility. It is now clear this not the case, and in recent years the molecular basis for these phenomena has become much better understood.


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