scholarly journals Megakaryocyte derived immune-stimulating cells regulate host-defense immunity against bacterial pathogens

2021 ◽  
Author(s):  
Jin Wang ◽  
Jiayi Xie ◽  
Xue Han ◽  
Daosong Wang ◽  
Minqi Chen ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell ◽  
Bacterial Infection ◽  
Host Defense ◽  
T Cell Activation ◽  
Cell Activation ◽  
Hematopoietic Stem ◽  
Bacterial Response ◽  
Stem Cell Quiescence ◽  
Express Cell

Megakaryocytes (MKs) continuously produce platelets in bone marrow to support hemostasis. However, MKs also play roles beyond thrombopoiesis as they regulate hematopoietic stem cell quiescence and erythropoiesis, which suggests the functional heterogeneity of MKs. Here, using single-cell sequencing we identified an MK-derived immune-stimulating cell (MDIC) population, which plays an important role in host-protective response against bacteria. In contrast to platelet-generating MKs, MDICs highly express cell migration, immune-modulatory, and response genes. Upon Listeria (L.) monocytogenes infection, MDICs egress to circulation and infiltrate into the spleen, liver and lung. MDICs interact with myeloid cells to promote their migration and tissue infiltration. More importantly, MDICs stimulate phagocytosis of macrophages and neutrophils by producing TNFα and IL-6 and facilitating antigen-specific T cell activation via IL-6 to enhance anti-bacterial response. Ablation of MKs reduced innate immune response and compromised T cell activation in spleen and liver, impairs the anti-bacterial effects in mice under L. monocytogenes challenge. Finally, infection-induced emergency megakaryopoiesis efficiently stimulated MDICs generation upon bacterial infection. Overall, we identify MDICs as a novel MK subpopulation, which regulates host-defense immune response against bacterial infection.

scholarly journals Cross-Presentation of Male Seminal Fluid Antigens Elicits T Cell Activation to Initiate the Female Immune Response to Pregnancy

2009 ◽  
Vol 182 (12) ◽  
pp. 8080-8093 ◽  
Author(s):  
Lachlan M. Moldenhauer ◽  
Kerrilyn R. Diener ◽  
Dougal M. Thring ◽  
Michael P. Brown ◽  
John D. Hayball ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Seminal Fluid ◽  
Cross Presentation

scholarly journals Distinct cellular immune profiles in the airways and blood of critically ill patients with COVID-19

2020 ◽  
Author(s):  
Anno Saris ◽  
Tom D.Y. Reijnders ◽  
Esther J. Nossent ◽  
Alex R. Schuurman ◽  
Jan Verhoeff ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Peripheral Blood ◽  
Cell Activation ◽  
Effector Memory ◽  
Activated T Cells ◽  
Immune Profile ◽  
Prolonged Icu Stay

AbstractOur understanding of the coronavirus disease-19 (COVID-19) immune response is almost exclusively derived from studies that examined blood. To gain insight in the pulmonary immune response we analysed BALF samples and paired blood samples from 17 severe COVID-19 patients. Macrophages and T cells were the most abundant cells in BALF. In the lungs, both CD4 and CD8 T cells were predominantly effector memory cells and expressed higher levels of the exhaustion marker PD-1 than in peripheral blood. Prolonged ICU stay associated with a reduced proportion of activated T cells in peripheral blood and even more so in BALF. T cell activation in blood, but not in BALF, was higher in fatal COVID-19 cases. Increased levels of inflammatory mediators were more pronounced in BALF than in plasma. In conclusion, the bronchoalveolar immune response in COVID-19 has a unique local profile that strongly differs from the immune profile in peripheral blood.SummaryThe bronchoalveolar immune response in severe COVID-19 strongly differs from the peripheral blood immune profile. Fatal COVID-19 associated with T cell activation blood, but not in BALF.

scholarly journals The Regulation of the CNS Innate Immune Response Is Vital for the Restoration of Tissue Homeostasis (Repair) after Acute Brain Injury: A Brief Review

2010 ◽  
Vol 2010 ◽  
pp. 1-18 ◽  
Author(s):  
M. R. Griffiths ◽  
P. Gasque ◽  
J. W. Neal
Keyword(s):  
Stem Cells ◽  
Immune Response ◽  
T Cell ◽  
Innate Immune Response ◽  
T Cell Activation ◽  
Cell Activation ◽  
Tissue Homeostasis ◽  
Innate Immune ◽  
Apoptotic Cells ◽  
Treg Population

Neurons and glia respond to acute injury by participating in the CNS innate immune response. This involves the recognition and clearance of “not self ” pathogens and “altered self ” apoptotic cells. Phagocytic receptors (CD14, CD36, TLR–4) clear “not self” pathogens; neurons and glia express “death signals” to initiate apoptosis in T cells.The complement opsonins C1q, C3, and iC3b facilitate the clearance of apoptotic cells by interacting with CR3 and CR4 receptors. Apoptotic cells are also cleared by the scavenger receptors CD14, Prs-R, TREM expressed by glia. Serpins also expressed by glia counter the neurotoxic effects of thrombin and other systemic proteins that gain entry to the CNS following injury. Complement pathway and T cell activation are both regulated by complement regulatory proteins expressed by glia and neurons. CD200 and CD47 are NIRegs expressed by neurons as “don't eat me” signals and they inhibit microglial activity preventing host cell attack. Neural stem cells regulate T cell activation, increase the Treg population, and suppress proinflammatory cytokine expression. Stem cells also interact with the chemoattractants C3a, C5a, SDF-1, and thrombin to promote stem cell migration into damaged tissue to support tissue homeostasis.

scholarly journals Passively transferred IgG enhances humoral immunity to a red blood cell alloantigen in mice

2020 ◽  
Vol 4 (7) ◽  
pp. 1526-1537
Author(s):  
David R. Gruber ◽  
Amanda L. Richards ◽  
Heather L. Howie ◽  
Ariel M. Hay ◽  
Jenna N. Lebedev ◽  
...  
Keyword(s):  
Immune Response ◽  
T Cell ◽  
T Cell Activation ◽  
Humoral Immunity ◽  
Cell Activation ◽  
Adaptive Immune Response ◽  
Immunoglobulin M ◽  
Third Party ◽  
Cd4 T Cell ◽  
Specific Subset

Abstract Antibodies are typically thought of as the endpoint of humoral immunity that occur as the result of an adaptive immune response. However, affinity-matured antibodies can be present at the initiation of a new immune response, most commonly because of passive administration as a medical therapy. The current paradigm is that immunoglobulin M (IgM), IgA, and IgE enhance subsequent humoral immunity. In contrast, IgG has a “dual effect” in which it enhances responses to soluble antigens but suppresses responses to antigens on red blood cells (RBCs) (eg, immunoprophylaxis with anti-RhD). Here, we report a system in which passive antibody to an RBC antigen promotes a robust cellular immune response leading to endogenous CD4+ T-cell activation, germinal center formation, antibody secretion, and immunological memory. The mechanism requires ligation of Fcγ receptors on a specific subset of dendritic cells that results in CD4+ T-cell activation and expansion. Moreover, antibodies cross-enhance responses to a third-party antigen, but only if it is expressed on the same RBC as the antigen recognized by the antibody. Importantly, these observations were IgG subtype specific. Thus, these findings demonstrate that antibodies to RBC alloantigens can enhance humoral immunity in an IgG subtype-specific fashion and provide mechanistic elucidation of the enhancing effects.

scholarly journals Molecular Profiling of Acute and Chronic Rejections of Renal Allografts

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Hřibová Petra ◽  
Honsová Eva ◽  
Brabcová Irena ◽  
Hrubá Petra ◽  
Viklický Ondřej
Keyword(s):  
Immune Response ◽  
T Cell ◽  
T Cell Activation ◽  
Chronic Rejection ◽  
Cell Activation ◽  
Expression Patterns ◽  
B Cell Activation ◽  
Graft Dysfunction ◽  
Gene Expressions ◽  
Lower Expression

Both antibody mediated (AMR) and T-cell mediated (TCMR) rejections either acute or chronic represent the main reason for late graft dysfunction. In this study we aimed to evaluate differences in the intrarenal expression patterns of immune system related genes in acute and chronic rejections. Graft biopsies were performed and evaluated according to Banff classification. Using the TaqMan Low Density Array, the intrarenal expressions of 376 genes relating to immune response (B-cell activation, T-cell activation, chemokines, growth factors, immune regulators, and apoptosis) were analyzed in the four rejection categories: chronic AMR, chronic TCMR, acute AMR, and acute TCMR. The set of genes significantly upregulated in acute TCMR as compared to acute AMR was identified, while no difference in gene expressions between chronic rejections groups was found. In comparison with functioning grafts, grafts that failed within the next 24 months after the chronic rejection morphological confirmation presented at biopsy already established severe graft injury (low eGFR, higher proteinuria), longer followup, higher expression of CDC20, CXCL6, DIABLO, GABRP, KIAA0101, ME2, MMP7, NFATC4, and TGFB3 mRNA, and lower expression of CCL19 and TRADD mRNA. In conclusion, both Banff 2007 chronic rejection categories did not differ in intrarenal expression of 376 selected genes associated with immune response.

Next Generation of Immunotherapy for Melanoma

2008 ◽  
Vol 26 (20) ◽  
pp. 3445-3455 ◽  
Author(s):  
John M. Kirkwood ◽  
Ahmad A. Tarhini ◽  
Monica C. Panelli ◽  
Stergios J. Moschos ◽  
Hassane M. Zarour ◽  
...  
Keyword(s):  
Immune Response ◽  
Immune System ◽  
T Cell ◽  
Immune Responses ◽  
T Cell Activation ◽  
Cell Activation ◽  
The United States ◽  
Cytotoxic Agents ◽  
Antitumor Immune Response ◽  
Phase Iii

PurposeImmunotherapy has a long history with striking but limited success in patients with melanoma. To date, interleukin-2 and interferon-alfa2b are the only approved immunotherapeutic agents for melanoma in the United States.DesignTumor evasion of host immune responses, and strategies for overcoming tumor-induced immunosuppression are reviewed. Several novel immunotherapies currently in worldwide phase III clinical testing for melanoma are discussed.ResultsThe limitations of immunotherapy for melanoma stem from tumor-induced mechanisms of immune evasion that render the host tolerant of tumor antigens. For example, melanoma inhibits the maturation of antigen-presenting cells, preventing full T-cell activation and downregulating the effector antitumor immune response. New immunotherapies targeting critical regulatory elements of the immune system may overcome tolerance and promote a more effective antitumor immune response. These include monoclonal antibodies that block the cytotoxic T lymphocyte-associated antigen 4 (CTLA4) and toll-like receptor 9 (TLR9) agonists. Blockade of CTLA4 prevents inhibitory signals that downregulate T-cell activation. TLR9 agonists stimulate dendritic cell maturation and ultimately induce a more effective immune response. These approaches have been shown to stimulate acute immune activation with concomitant appearance of transient adverse events mediated by the immune system. The pattern and duration of immune responses associated with these new modalities differ from those associated with cytokines and cytotoxic agents. In addition, vaccines are being developed that may ultimately target melanoma either alone or in combination with these immunomodulatory therapies.ConclusionThe successes of cytokine and interferon therapy of melanoma, coupled with an array of new approaches, are generating new enthusiasm for the immunotherapy of melanoma.

Clinical Trial of Therapeutic Blockade of CTLA4 with Ipilimumab in Patients with Relapse of Malignancy Following Allogeneic Hematopoietic Transplantation.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 1646-1646
Author(s):  
Asad Bashey ◽  
Bridget Medina ◽  
Sue Corringham ◽  
Mildred Pasek ◽  
Ewa Carrier ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Activation ◽  
Cell Activation ◽  
Human Monoclonal Antibody ◽  
Negative Regulator ◽  
Dose Escalation Study ◽  
Hematopoietic Stem ◽  
Objective Evidence ◽  
Anti Cancer ◽  
Grade 3

Abstract Relapse/progression of malignancy (RM) is an important cause of treatment failure and death following allogeneic hematopoietic stem cell transplantation (allo-HCT). CTLA-4 is an important negative regulator of effector T-cell activation. CTLA-4 inhibition has demonstrated potent anti-cancer effects in animal models, and in patients with some solid tumors. CTLA-4 blockade following allo-HCT may potentially augment graft-versus-malignancy but GVHD may also possibly be increased. We report the safety and preliminary efficacy of a dose-escalation study of a neutralizing human monoclonal antibody targeting CTLA-4 (ipilimumab) in patients with RM following allo-HCT. Eligibility criteria included allo-HCT ≥90 days previously, > 50% donor T-cell chimerism, no prior grade 3/4 GVHD, no prophylaxis/therapy for GVHD for ≥ 6 weeks. Patients received a single dose of ipilimumab over 90 min. DLI at a dose of 5 × 10e6 CD3 cells/kg was allowed 8 weeks following ipilimumab if no GVHD occurred and RM was present. A total of 29 patients were treated at four centers (23M, 6F; median age 43 (21–65); Hodgkins disease [HD] =14 Myeloma [MM]=6, CML=2, CLL=2, AML=2, NHL=1, Renal Ca =1, Breast Ca=1; 19 related donors, 10 unrelated; 6 myeloablative, 23 RICT).(4 at dose-level 1 [DL1] 0.1 mg/kg, 3 at 0.33 mg/kg [DL2], 4 at 0.66 mg/kg [DL3], 3 at 1.0 mg/kg [DL4] and 15 at 3.0 mg/kg [DL5]). Eight patients had failed prior DLI. Median time between BMT and ipilimumab was 366 d (125–2368). Dose-limiting toxicity was not encountered. No patient developed clinically significant GVHD within 90 days following ipilimumab alone. Three possible immune adverse events were documented: grade 3 polyarthropathy 14 weeks following ipilimumab, and 6 weeks post DLI, which resolved with corticosteroid therapy, (AML, DL1); grade 1 hyperthyroidism with thyroid-stimulating antibody 6 weeks post ipilimumab (CLL, DL3). Grade 2 pneumonitis responsive to corticosteroids (HD, DL5). Ten patients received DLI after ipilimumab. Three patients developed objective evidence of disease response after ipilimumab alone: PR in a patient with mantle cell NHL lasting 3m [DL4]; ongoing CR in a two patients with HD [DL5]. Two of these patients had failed prior DLI. Three additional patients demonstrated possible anti-cancer effects (MR in a HD patient, reduction of PB and BM blasts in AML, DL1; maintenance of molecular remission in a CML patient given ipilimumab alone for 3.5 yrs despite stopping imatinib, DL1). This study shows that doses of ipilimumab (up to 3.0 mg/kg) can safely be administered to patients with RM following allo-HCT without inducing/exacerbating GVHD while inducing regressions of malignancy including durable CR in some patients.

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