scholarly journals Type IV Pili of Neisseria gonorrhoeae Influence the Activation of Human CD4+ T Cells

2006 ◽  
Vol 74 (1) ◽  
pp. 442-448 ◽  
Author(s):  
Laura J. Plant ◽  
Ann-Beth Jonsson

ABSTRACT Neisseria gonorrhoeae is the causative agent of the sexually transmitted disease gonorrhea, and infection with this organism is typically associated with an intense inflammatory response. In many individuals, however, the infection is asymptomatic and can progress to serious secondary complications. The type IV pili of Neisseria gonorrhoeae mediate binding of the bacteria to host cells and are involved in cellular signal transduction. In these studies we have demonstrated that gonococcal pili influence human CD4+ T cells by using isogenic strains of N. gonorrhoeae with piliated and nonpiliated phenotypes. To determine the impact of piliation on the cellular status, we examined the expression of activation markers, cellular proliferation, and the production of cytokines after infection. The activation marker CD69 showed significantly increased expression on cells infected with the piliated strain, and this expression was dependent on costimulation of the T-cell receptor. Infection with piliated gonococci also altered T-cell proliferation and influenced the production of the regulatory cytokine interleukin-10. PilC, the putative pilus adhesin, was also observed to influence cellular activation but had no impact on the proliferation of cells further indicating that pilus-mediated adhesion is important in gonococcal stimulation of CD4+ T cells. These results show that the piliation status of gonococci influences CD4+ T-cell activation and that the adhesion mediated by pilus components aids in the regulation of the T-cell response to N. gonorrhoeae.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiaohui Wang ◽  
Xiang Lin ◽  
Zihan Zheng ◽  
Bingtai Lu ◽  
Jun Wang ◽  
...  

AbstractInnate immunity is important for host defense by eliciting rapid anti-viral responses and bridging adaptive immunity. Here, we show that endogenous lipids released from virus-infected host cells activate lung γδ T cells to produce interleukin 17 A (IL-17A) for early protection against H1N1 influenza infection. During infection, the lung γδ T cell pool is constantly supplemented by thymic output, with recent emigrants infiltrating into the lung parenchyma and airway to acquire tissue-resident feature. Single-cell studies identify IL-17A-producing γδ T (Tγδ17) cells with a phenotype of TCRγδhiCD3hiAQP3hiCXCR6hi in both infected mice and patients with pneumonia. Mechanistically, host cell-released lipids during viral infection are presented by lung infiltrating CD1d+ B-1a cells to activate IL-17A production in γδ T cells via γδTCR-mediated IRF4-dependent transcription. Reduced IL-17A production in γδ T cells is detected in mice either lacking B-1a cells or with ablated CD1d in B cells. Our findings identify a local host-immune crosstalk and define important cellular and molecular mediators for early innate defense against lung viral infection.


Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 829 ◽  
Author(s):  
Klaus-Peter Künkele ◽  
Daniela Wesch ◽  
Hans-Heinrich Oberg ◽  
Martin Aichinger ◽  
Verena Supper ◽  
...  

Cancer therapies based on in vivo stimulation, or on adoptive T cell transfer of Vγ9Vδ2 T cells, have been tested in the past decades but have failed to provide consistent clinical efficacy. New, promising concepts such as γδ Chimeric Antigen Receptor (CAR) -T cells and γδ T-cell engagers are currently under preclinical evaluation. Since the impact of factors, such as the relatively low abundance of γδ T cells within tumor tissue is still under investigation, it remains to be shown whether these effector T cells can provide significant efficacy against solid tumors. Here, we highlight key learnings from the natural role of Vγ9Vδ2 T cells in the elimination of host cells bearing intracellular bacterial agents and we translate these into the setting of tumor therapy. We discuss the availability and relevance of preclinical models as well as currently available tools and knowledge from a drug development perspective. Finally, we compare advantages and disadvantages of existing therapeutic concepts and propose a role for Vγ9Vδ2 T cells in immune-oncology next to Cluster of Differentiation (CD) 3 activating therapies.


2002 ◽  
Vol 70 (1) ◽  
pp. 153-162 ◽  
Author(s):  
Amy R. Tvinnereim ◽  
Sara E. Hamilton ◽  
John T. Harty

ABSTRACT Understanding how existing antivector immunity impacts live vaccine delivery systems is critical when the same vector system may be used to deliver different antigens. We addressed the impact of antivector immunity, elicited by immunization with attenuated actA-deficient Listeria monocytogenes, on the CD8+-T-cell response to a well-characterized lymphocytic choriomeningitis virus epitope, NP118-126, delivered by infection with recombinant L. monocytogenes. Challenges of immune mice with actA-deficient and with wild-type recombinant L. monocytogenes generated similar numbers of CD8+ T cells specific for the NP118-126 epitope. High-dose immunization with actA-deficient L. monocytogenes resulted in substantial numbers of CD8+ T cells specific for the L. monocytogenes LLO91-99 epitope in the effector and memory stages of the T-cell response. Challenge of these immune mice with recombinant L. monocytogenes resulted in rapid control of the infection and decreased CD8+-T-cell responses against both the secreted and nonsecreted form of the recombinant antigen compared to the response of naïve mice. In contrast, mice immunized with a low dose of actA-deficient L. monocytogenes had ∼10-fold fewer effector and memory T cells specific for LLO91-99 and a substantially higher CD8+-T-cell response against the recombinant antigen after challenge with recombinant L. monocytogenes. Although mice immunized with low-dose actA-deficient L. monocytogenes had a substantial recall response to LLO91-99, which reached the same levels by 5 to 7 days postchallenge as that in high-dose-immunized mice, they exhibited decreased ability to control L. monocytogenes replication. Thus, the level of antivector immunity impacts the control of infection and efficiency of priming responses against new antigens introduced with the same vector.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3106-3106
Author(s):  
Bruno Nervi ◽  
Michael P. Rettig ◽  
Julie K. Ritchey ◽  
Gerhard Bauer ◽  
Jon Walker ◽  
...  

Abstract GvHD remains a major cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation and donor lymphocyte infusion. The human GvHD pathophysiology includes recipient tissue destruction and proinflammatory cytokine production associated with the conditioning regimen; donor T cells become allo-activated, proliferate, and mediate tissue injury in various organs, including the liver, skin, and gut. Modern therapeutic strategies to control GvHD while maintaining the beneficial graft-versus-leukemia effects require ex vivo T cell stimulation and expansion. Multiple studies have demonstrated that these ex vivo expanded T cells exhibit decreased survival and function in vivo, including reduced alloreactivity and GvHD potential. Unfortunately no in vivo models exist to consistently examine the impact of ex vivo manipulation of human T cells (HuT) on T cell function. Naive HuT were compared to HuT activated using CD3/28 beads (XcyteTMDynabeads) with 50 U/ml IL-2 for 4 days (Act). We initially evaluated the HuT engraftment and GvHD potential of naive and Act in RAG2γ null mice (n=22) conditioned with clodronate liposomes on day −1 and 350cGy on day 0, as previously described by others. We injected 107 and 1.5x107 naive or Act HuT intravenously (iv). All mice exhibited low HuT engraftment and no lethal GvHD. NOD SCIDβ 2M null mice (β 2M) were next conditioned with 250cGy on day −1 (n=34), or 300cGy on day 0 (n=21). 107 naive vs Act HuT were injected retroorbitaly (ro). Lower HuT doses or iv injection resulted in no expansion or GvHD. Engraftment of HuT in peripheral blood of recipient mice was evaluated weekly by FACS and euthanasia was performed if mice lost > 20% body weight. 60% of the mice conditioned with 250cGy that received naive HuT developed lethal GvHD, in comparison to 75% of mice that received 300cGy and nave HuT, and 100% of mice that received 300cGy and Act HuT. Table 1 250cGy 300cGy Naive (n=34) Naive (n=8) Activated (n=13) *p<0.02 PB engraftment (%HuT) 20%±15 33%±21 59%±19 Lethal GvHD 60% 75% 100% All mice receiving 300cGy had well preserved CD4/CD8 ratios (1–1.5). Tissue infiltration was greatest in mice that had received 300cGy and Act HuT (spleen, liver, lung, kidney: 50–70%). Of interest, serum levels of hu IFNγ dramatically increased over time in all mice who went on to develop lethal GvHD (day 3=270 ug/ml and day 15=36,000 ug/ml) compared to mice that did not develop lethal GvHD (day 10=40 ug/ml and day 17=1,020 ug/ml)(p<0.05). Interestingly, the up-regulation of the activation markers CD25 and CD30 in HuT, and IFNγ production predicted lethal GvHD in β 2M null mice. In summary, we developed a xenogeneic model of lethal GvHD where naive or ex vivo Act HuT injected ro in sublethaly irradiated β 2M not only engraft, expand in vivo, but also infiltrate and damage different mouse target organs. HuT are allo-activated against mouse antigens and damage the target tissues, sharing the major characteristics of human GvHD and causing the death of mice. This model will allow us to study the effects of specific ex vivo T cell manipulation including transduction, selection, expansion, and the depletion or addition of various T cells and other cellular subsets on the outcome of GvHD, to determine improved therapeutic interventions.


2006 ◽  
Vol 74 (2) ◽  
pp. 1001-1008 ◽  
Author(s):  
Christine A. Shaw ◽  
Michael N. Starnbach

ABSTRACT Recognition and clearance of many intracellular pathogens requires the activation and subsequent effector functions of CD8+ T lymphocytes. To stimulate CD8+ T cells by immunization, the target antigens must be delivered into the cytosol of host cells. There they can be processed into peptides and presented in the context of major histocompatibility complex class I molecules to antigen-specific CD8+ T cells. One method of delivering antigens into the cytosol is to fuse them to modified bacterial toxins that are able to enter mammalian cells. The expression pattern of the toxin receptors in the host will determine the cell population that the toxin fusion protein targets and will thus restrict antigen-specific T-cell recognition to the same population. In this study we describe the development and characterization of a diphtheria toxin (DT)-based antigen delivery system. Using CD11c-DTR transgenic mice that express the DT receptor in dendritic cells (DC), this system allows for targeted delivery of CD8+ T-cell antigen to DC. We show that antigen-specific CD8+ T cells proliferate in CD11c-DTR mice following immunization with catalytically inactive DT-antigen fusion proteins. We also show that a toxin-based system that restricts antigen delivery to DC results in more robust antigen-specific CD8+ T-cell proliferation than a toxin-based system that does not restrict delivery to a particular cell type. These results have implications for vaccine design, and they suggest that use of a toxin-based vector to target antigen to DC may be an effective way to induce a CD8+ T-cell response.


2021 ◽  
Author(s):  
◽  
Haley Ataera

<p>The adoptive transfer of activated dendritic cells (DC) loaded with tumour antigen or tumour specific T cells improves weak anti-tumour responses, however, without treatments to relieve suppression, these therapies will continue to fall short of their full potential. The aim of this thesis was to understand the role of hypoxia-induced increases in adenosine and of CD4+ CD25+ Foxp3+ regulatory T cells (Treg) in the suppression of anti-tumour immune responses and to design strategies to abrogate these mechanisms. These aims were investigated using the B16.OVA murine melanoma model because the OVA specific CD4+ (OTII) and CD8+ (OTI) T cell transgenic mice allowed detailed investigation of Ag specific T cell responses. Recent studies have shown that the inhibition of adenosine signalling in activated CD8+ T cells can improve the anti-tumour activity of these cells. To investigate these findings using the B16.OVA model, tumour-bearing mice were given activated OTI T cells and the adenosine receptor inhibitor caffeine. Caffeine treatment did not improve the anti-tumour response, possibly because this response was suppressed due to the increased frequency of myeloid derived suppressor cells observed in mice that received T cells. To determine whether the defective function of tumour infiltrating DC (TIDC) in tumours is due to suppression by Treg, mice were treated with the anti-CD25 monoclonal antibody PC61 to deplete Treg and challenged with tumours. PC61 treatment caused a delay in tumour growth but did not affect DC frequency, or expression of the DC activation markers CD40, CD86 and MHC II in tumours or lymph nodes. DC function was tested using in vitro and in vivo T cell proliferation assays and was found to be unaffected by PC61 treatment. Studies in RAG1-/- mice, which lack Treg, also showed no improvement in DC activation status or function. These results show that Treg do not suppress TIDC in the B16.OVA model. It is well known, however, that Treg suppress T cell responses and it has been suggested that Treg may mediate some of this suppression by using the perforin-granzyme pathway to cause T cell death. To investigate this possibility, naive, perforin sufficient OTI T cells were transferred into normal and perforin knockout (PKO) mice, with or without PC61 treatment. To stimulate an OTI T cell response, mice also received OVA-loaded DC. Depletion of both normal and PKO Treg resulted in decreased death and increased proliferation of the transferred cells, increased expression of IFN-y and TNF-a, and improved in vivo target cell killing by the transferred cells. These findings indicate that perforin expression by Treg is not required to suppress T cell responses or cause T cell death. In conclusion, the results of this thesis were consistent with the observation that there are multiple suppressive mechanisms in tumours and that there is substantial redundancy of these mechanisms. Depletion of Treg was found to improve the anti-tumour response, however, suppression of the DC was still evident, demonstrating that the neutralisation of a single suppressive mechanism may not be sufficient to treat aggressive, late stage cancers such as melanoma.</p>


Circulation ◽  
2012 ◽  
Vol 125 (suppl_10) ◽  
Author(s):  
Roksana Karim ◽  
Naoko Kono ◽  
Robert Kaplan ◽  
Wendy J Mack ◽  
Howard N Hodis ◽  
...  

Introduction: Activation of T-lymphocytes, a hallmark of HIV infection, reaches a set point early in HIV infection and persists even after viral suppression with highly active antiretroviral therapy (HAART). Early T-cell activation predicts subsequent CD4 depletion, progression to AIDS and survival. HIV-infected subjects are at high risk for premature atherosclerosis. Little is known regarding the impact of early T cell activation on arterial stiffness. While Kaplan et al. (2011) were the first and only group to show a cross-sectional association, we investigate here if early T cell activation can predict future arterial stiffness. Hypothesis: High early T cell activation will predict increased arterial stiffness, measured 5.5 (IQR=2.5-7.5) years later, in HIV and HCV co-infected women. Methods: A longitudinal study nested within the WIHS, an ongoing prospective cohort study. Percentages of CD4 and CD8 T cell activation, assessed by CD38 and HLA-DR co-expression using 3-color flow cytometry, were measured on average 5.5 years before arterial stiffness assessments (carotid artery distensibility, and Young’s elastic modulus for elasticity) using B-mode carotid ultrasound. Multiple linear regression models evaluated the association between log-transformed T cell activation markers (independent variables) and arterial stiffness (dependent variable). Analyses were stratified by HCV co-infection status and by pre- and post-HAART assessment of T cell activation. Results: A total of 376 HIV+ women (185 HCV+) were included in the analysis. Participants were on average 46(SD=9) years old, 59% Black, and 49% were current smokers. Activation of both CD4 and CD8 T cells significantly univariately predicted reduced distensibility and elasticity among HIV-infected women. CD4 activation continued to significantly predict distensibility (β(SEM)= −3.51(1.30) 10 −6* N −1* m 2 , p=0.01), and elasticity (0.11(0.04)10 5* N * m 2 , p=0.004) with adjustment for age, race, BMI, smoking, ART, CD4 count, and HIV RNA. CD8 activation was no longer associated after adjustment. When stratified by HCV co-infection status, the prediction of arterial stiffness parameters from early CD4 activation was somewhat stronger among the HIV+/HCV+ women compared to HIV+/HCV- women (β(SEM)= −4.44(1.93), p=0.02 vs. −3.04(1.84), p=0.10 for distensibility, and 0.17(0.06), p=0.003 vs. 0.09(0.05), p=0.09 for elasticity); however the test for interaction was not statistically significant. In a subset of 188 women, CD4 activation measured both pre- and post-HAART significantly predicted later arterial stiffness. Conclusions: CD4 activation level predicts future arterial stiffness in HIV-infected women, perhaps more markedly among HCV co-infected women. These data confirm the proinflammatory impact of activated T cells that can cause vascular dysfunction and shed light on the early onset of atherogenesis.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4839-4839
Author(s):  
Anne Richter ◽  
Michaela Niemöller ◽  
Inken Verwohl ◽  
Katrin Lange ◽  
Anna Foerster-Marniok ◽  
...  

Abstract Abstract 4839 Functional characterizations of T lymphocytes are performed to gain understanding on their contribution in certain immunological situations, to monitor the course of diseases, and to track therapeutic interventions. Meanwhile the flow cytometric analysis of antigen-specific T cells examined for intracellular cytokine production and expression of activation markers after a short-term in vitro antigenic challenge is a well-established method for research applications. Despite the advantages of this approach to qualify samples on a single cell level and by multiple parameters, the broad use of this analysis for immune monitoring purposes is hampered. Screening of a lot of samples is time-consuming, requires many manual handling steps, and operator experience in flow cytometric analysis of stimulated T cell samples. To overcome these hurdles, we worked out a complete strategy to rapidly study cytokine and activation marker profiles in antigen-specific T cells of multiple samples by a semi-automated process. For the simultaneous analysis of multiple samples we examined for the T cell stimulation an antigen pre-coated 96-strip-well culture system. This flexible and ready-to-use format provides the opportunity to screen either for a single antigen or in parallel for up to twelve antigen specificities by combining 8-well-strips possessing different antigens. The coated antigens consist of pools of overlapping 15-mer peptides derived from a single viral protein of cytomegalovirus, Epstein-Barr-Virus, or adenovirus. The peptide pools have been designed for activation of the specific CD4+ as well as CD8+ T cells. They are solubilized and thereby accessible for T cell stimulation after addition of a cell sample, e.g. peripheral blood mononuclear cells, suspended in culture medium into the antigen-coated well. After a stimulation period of six hours the induced T cell response is comparable to the activation with a conventional lyophilized and reconstituted peptide pool. To reduce the time and work load for cell harvesting, fixation, permeabilization, and staining, we developed a protocol and reagents to allow a rapid and easy-to-handle intracellular staining procedure. Compared to conventional staining protocols, all steps are executed in the 96-strip-well culture plate, i.e. cell harvesting is dispensable. Without any washing step, cells are fixed and stained with defined reagent cocktails containing antibodies to identify virus-specific CD3+ CD4+ CD154+ and/or CD3+ CD8+ T cells and various Anti-cytokine-fluorochrome conjugates to evaluate the cytokine pattern. With these modifications, we drastically diminished the overall processing time for the staining of up to 96 samples to only 50 minutes. Furthermore, we integrated an automated flow cytometric analysis process. This includes the possibility to measure the samples in the 96-strip-well plates hands-free using pre-defined experiment settings and acquisition templates. We also applied an automated gating strategy for the data analysis. Finally, a report summarizes the results of the T cell response against several viral proteins for all samples tested, e.g. frequencies of cytokine+ CD154+ CD4+ and cytokine+ CD8+ T cell subsets are indicated. Hands-on time for the multi-sample acquisition and analysis is only minimal and the standardized reagents/protocol and sample analysis process decrease inter- and intra-assay variations. In summary, with our newly developed tools and protocols for in vitro T cell stimulation, staining of activation markers as well as intracellular cytokines, and automated flow cytometric analysis we have set up a fast and convenient procedure to routinely monitor antigen-specific T cell responses. Disclosures: Richter: Miltenyi Biotec GmbH: Employment. Niemöller:Miltenyi Biotec GmbH: Employment. Verwohl:Miltenyi Biotec GmbH: Employment. Lange:Miltenyi Biotec GmbH: Employment. Foerster-Marniok:Miltenyi Biotec GmbH: Employment. Brauns:Miltenyi Biotec GmbH: Employment. Kramer:Miltenyi Biotec GmbH: Employment. Höher-Peters:Miltenyi Biotec GmbH: Employment. Büscher:Miltenyi Biotec GmbH: Employment. Assenmacher:Miltenyi Biotec GmbH: Employment. Schmitz:Miltenyi Biotec GmbH: Employment.


2021 ◽  
Vol 11 ◽  
Author(s):  
Hongyan Liu ◽  
Shishuo Sun ◽  
Gang Wang ◽  
Mengmeng Lu ◽  
Xiaokang Zhang ◽  
...  

BackgroundAdvanced renal cell carcinoma (RCC) has a very dismal prognosis. Cabozantinib, a tyrosine kinase inhibitor, has been approved for the treatment of advanced RCC. However, the impact of cabozantinib on the immune microenvironment of RCC remains poorly understood.MethodsKaplan-Meier survival curves were constructed to examine the correlation between intratumor infiltration of neutrophils and patient prognosis in RCC. Infiltration and effector function of neutrophils and T cells in response to cabozantinib treatment were investigated in a murine RCC model.ResultsA retrospective study of 307 RCC patients indicated that neutrophils were recruited into tumor tissues, and increased neutrophil infiltration was associated with improved clinical outcomes. In a murine model of RCC, cabozantinib treatment significantly increased both intratumor infiltration and anti-tumor function of neutrophils and T cells. Mechanistically, we found that cabozantinib treatment induced expression of neutrophil-related chemokines (CCL11 and CXCL12) and T cell-related chemokines (CCL8 and CX3CL1) in the tumor microenvironment. Furthermore, depletion of neutrophils and CD8+ T cells compromised the therapeutic efficacy of cabozantinib. Importantly, cabozantinib treatment induced long-term anti-tumor T cell response.ConclusionsOur study revealed novel mechanisms of the therapeutic effects of cabozantinib on RCC by activating both neutrophil-mediated innate immunity and T cell-mediated adaptive immunity. These findings are of great significance for guiding the clinical use of cabozantinib and provide a good candidate for future combination therapy with T-cell therapies or other immunotherapies.


2019 ◽  
Vol 17 (3) ◽  
pp. 183-189
Author(s):  
Francesca Falasca ◽  
Eugenio Nelson Cavallari ◽  
Giuseppe Pietro Innocenti ◽  
Carolina Scagnolari ◽  
Ivano Mezzaroma ◽  
...  

Objectives: The aim of the study was to investigate if the supplementation with multistrain probiotics may be able to modulate T cell response in HIV-1 infected patients and to evaluate the anti-HIV activity of probiotic by studying fecal water (FW) samples. Methods: Three HIV-1-positive patients (Pt1, Pt2 and Pt3) on long-term suppressive combined antiretroviral therapy (cART) received a specific multi-strain probiotic supplementation (Vivomixx ®), for six months (T6). Levels of T cell subsets were evaluated by flow cytometry. Anti- HIV activity of FW samples was evaluated in vitro. Results: CD4+ T cells levels increased in all HIV-1 infected patients whereas activation markers (CD38 and HLA-DR) were decreased both on CD4+ and CD8+ T cells. FW samples presented an increased inhibitory activity against HIV-1 compared to T0 (FW-Pt1: T0 =40%, T6 = 65% of reduction; FW Pt2: T0 = 26%, T6 = 46% of reduction; FW Pt3: T0 = 47%, T6 = 94% of reduction). Discussion: Our data suggest that the administration of the specific probiotic formulation improves the antiviral status of people living with HIV-1 under cART, also modulating T cell response. Conclusion: Anti-HIV activity of FW may have several public health and social implications for sexually transmitted diseases that need to be further explored.


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