scholarly journals Immune CD8+ T Cells Prevent Reactivation of Toxoplasma gondii Infection in the Immunocompromised Host

1999 ◽  
Vol 67 (11) ◽  
pp. 5869-5876 ◽  
Author(s):  
Imtiaz A. Khan ◽  
William R. Green ◽  
Lloyd H. Kasper ◽  
Kathy A. Green ◽  
Joseph D. Schwartzman
Keyword(s):  
T Cells ◽  
Toxoplasma Gondii ◽  
Cell Function ◽  
Immunocompromised Host ◽  
Histopathological Analysis ◽  
Immunosuppressed Patients ◽  
Ifn Γ ◽  
Immunocompromised State ◽  
Toxoplasma Gondii Infection ◽  
Cellular Immune

ABSTRACT Toxoplasma gondii remains a serious cause of morbidity and mortality in individuals that are immunosuppressed, patients with AIDS in particular. The cellular immune response, especially by gamma interferon (IFN-γ)-producing CD8+ T cells, is an essential component of protective immunity against the parasite. In the present study the role of CD8+ T cells during the reactivation of Toxoplasma infection in an immunocompromised murine model was evaluated. Chronically infected mice were challenged with LP-BM5 virus, and the kinetics of CD8+T-cell function was studied. At 10 weeks after viral infection, mice showed obvious signs of systemic illness and began to die. At this stage, CD8+ T cells were unresponsive to antigenic stimulation and unable to kill Toxoplasma-infected targets. IFN-γ production by the CD8+ T cells from dual-infected animals reached background levels, and a dramatic fall in the frequency of precursor cytotoxic T lymphocytes was observed. Histopathological analysis of the tissues demonstrated signs of disseminated toxoplasmosis as a result of reactivation of infection. However, treatment of the dual-infected animals with immune CD8+ T cells at 5 weeks post-LP-BM5 challenge prevented the reactivation of toxoplasmosis, and mice continued to live. Our study for the first time demonstrates a therapeutic role for CD8+ T cells against an opportunistic infection in an immunocompromised state.

scholarly journals Dynamic Expressions of TIGIT on Splenic T Cells and TIGIT-Mediated Splenic T Cell Dysfunction of Mice With Chronic Toxoplasma gondii Infection

2021 ◽  
Vol 12 ◽  
Author(s):  
Haoran Li ◽  
Jing Zhang ◽  
Changwei Su ◽  
Xiaowei Tian ◽  
Xuefang Mei ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Toxoplasma Gondii ◽  
Cell Function ◽  
Immune Cell ◽  
Rt Pcr ◽  
Cell Dysfunction ◽  
T Cell Dysfunction ◽  
Toxoplasma Gondii Infection ◽  
Cellular Immune

As an immunosuppressive receptor, T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) play a critical part in cellular immune regulation mediated by pathogen infection. Whereas, TIGIT expression on splenic T cells in hosts infected with Toxoplasma gondii cysts has not been studied. In this study, we detected TIGIT expression and the changes of immune function in the spleen by flow cytometry and real-time PCR (RT-PCR). We found that TIGIT expression on splenic T cells increased significantly post infection. At the same time, splenic TIGIT+TCM cells were activated and transformed into TIGIT+TEM cells during the infection, and the cytotoxicity of TIGIT+ T cells was reduced in the later stage of infection. This study shows that chronic T. gondii infection can upregulate TIGIT expression on the surface of T cells and affect immune cell function.

scholarly journals Requirement of Non-T Cells That Produce Gamma Interferon for Prevention of Reactivation of Toxoplasma gondii Infection in the Brain

2001 ◽  
Vol 69 (5) ◽  
pp. 2920-2927 ◽  
Author(s):  
Hoil Kang ◽  
Yasuhiro Suzuki
Keyword(s):  
T Cells ◽  
Toxoplasma Gondii ◽  
Nk Cells ◽  
Gamma Interferon ◽  
Scid Mice ◽  
Toxoplasmic Encephalitis ◽  
Cell Transfer ◽  
Ifn Γ ◽  
Toxoplasma Gondii Infection ◽  
The Brain

ABSTRACT We examined the mechanism of resistance against reactivation of infection with Toxoplasma gondii in the brain. BALB/c-background gamma interferon (IFN-γ)-knockout (IFN-γ−/−) and control mice were infected and treated with sulfadiazine beginning 4 days after infection for 3 weeks. After discontinuation of treatment, IFN-γ−/− mice succumbed to toxoplasmic encephalitis (TE) and died, whereas control animals did not develop TE and survived. Adoptive transfer of immune spleen cells from infected control mice did not prevent development of TE or mortality in the IFN-γ−/− mice. To examine whether the failure of the cell transfer to protect against TE is unique to IFN-γ−/− mice, athymic nude and SCID mice that lack T cells were infected and injected with the immune spleen or T cells in the same manner as IFN-γ−/− mice. Whereas control nude and SCID mice that had not received the immune cells developed severe TE and died after discontinuation of sulfadiazine, those that had received the cells did not develop TE and survived. Before cell transfer, IFN-γ mRNA was detected in brains of infected nude and SCID but not in brains of IFN-γ−/− mice. IFN-γ mRNA was also detected in brains of infected SCID mice depleted of NK cells by treatment with anti-asialo GM1 antibody, and such animals did not develop TE after receiving immune T cells. Thus, IFN-γ production by non-T cells, in addition to T cells, is required for prevention of reactivation of T. gondii infection in the brain. The IFN-γ-producing non-T cells do not appear to be NK cells.

scholarly journals Amygdalin promotes the activity of T cells to suppress the progression of HBV-related hepatocellular carcinoma via the JAK2/STAT3 signaling pathway

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ruoyu Wang ◽  
Dong Zhang ◽  
Kewei Sun ◽  
Jianping Peng ◽  
Wenfang Zhu ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
Cell Viability ◽  
Caspase 3 ◽  
Invasion And Migration ◽  
Ifn Γ ◽  
And Migration ◽  
Cellular Immune

Abstract Background Hepatitis B virus (HBV) infection is a high-risk factor of hepatocellular carcinoma (HCC). Cellular immune responses are essential for HCC development, and the CD4+ and CD8+ T subtypes are identified as the primary anti-tumor immune cells. In the study, we investigated the effect and mechanism of amygdalin in the cellular immune response in HBV-related HCC and HCC progression. Methods The cell proliferation was examined by MTT analysis. Cells metastasis ability was detected by Invasion and migration assays. Quantification of apoptotic cells was performed with Flow cytometer assay. The protein levels of p-STAT3, STAT3, p-JAK2, JAK2, caspase-3, cleaved caspase-3 were detected by performing immunoblotting assays. Results We demonstrate that amygdalin treatment could rescue the HBV-T cell viability and IFN-γ and TNF-αproduction. In HBV-T cells, the MFI levels of CD8+ are lower than that in NC-T cells. Moreover, the phosphorylation levels of STAT3 and JAK2 are higher in HBV-T cells, compared to those in NC-T cells, and then reduced by amygdalin treatment. Co-culture with HBV-T cells could reduce IFN-γ and TNF-α, production while increase IL-6 and IL-10 production in HepG2.2.15 cells; these alterations could be partially reversed by amygdalin pretreatment. Finally, co-culture with HBV-T cells significantly promoted the cell viability, inhibited the apoptosis, and promoted the migration of HepG2.2.15 cells, and these alterations could be partially reversed by amygdalin treatment. Conclusion Our findings provide a rationale for further studies on the functions and mechanism of amygdalin inhibiting HBV-related HCC cell proliferation, invasion, and migration via T cell-mediated tumor immunity.

scholarly journals Histopathological analysis of the reproductive system of male dogs experimentally infected with Toxoplasma gondii

2009 ◽  
Vol 39 (7) ◽  
pp. 2123-2127 ◽  
Author(s):  
Tiago Pereira Arantes ◽  
Welber Daniel Zanetti Lopes ◽  
Roberta Machado Ferreira ◽  
Juliana de Souza Pinto Pieroni ◽  
Vanessa Marigo Rocha Pinto ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Reproductive System ◽  
Interstitial Fibrosis ◽  
Optical Microscope ◽  
Seminiferous Tubules ◽  
Histopathological Analysis ◽  
Hydropic Degeneration ◽  
Toxoplasmic Infection ◽  
Toxoplasma Gondii Infection ◽  
Histopathological Results

The present research aimed to describe possible histopathological alterations in the reproductive system (testicles and epididymis) of male dogs experimentally infected with Toxoplasma gondii. Canines (n=10) serologically negative for T. gondii were selected and distributed into three experimental groups: GI, 3 inoculated with 2.0 x 10(5)P strain oocysts; GII, 3 infected with 1.0 x 10(6)RH strain tachyzoites; and GIII, 4 control dogs. Antibody research (IFAT) against T. gondii was realized. Toxoplasma gondii infection was confirmed by seroconversion of the 6 males infected with tachyzoites and oocysts from postinoculation day (PID) 7 and 14, respectively. At PID 70, all dogs were submitted to orchiectomy and testicle and epididymis samples were collected and histologically processed for examination under optical microscope. The following alterations were diagnosed: mild and moderate mononuclear inflammatory infiltrate in the epididymis, moderate cellular edema, hydropic degeneration and moderate interstitial fibrosis in seminiferous tubules. The histopathological results in the present research, isolation of T. gondii in testicle and epididymis fragments by immunohistochemistry and results from the literature by other authors in different tissues, all infer that the alterations observed in dogs infected with T. gondii are suggestive of toxoplasmic infection.

scholarly journals Complete Protection against Lethal Toxoplasma gondii Infection in Mice Immunized with a Plasmid Encoding theSAG1 Gene

1999 ◽  
Vol 67 (12) ◽  
pp. 6358-6363 ◽  
Author(s):  
Henrik Vedel Nielsen ◽  
Sanne Lise Lauemøller ◽  
Lone Christiansen ◽  
Søren Buus ◽  
Anders Fomsgaard ◽  
...  
Keyword(s):  
T Cells ◽  
Toxoplasma Gondii ◽  
Cytotoxic T Lymphocyte ◽  
Protozoan Parasite ◽  
Complete Protection ◽  
Effective Protection ◽  
Partial Protection ◽  
Empty Plasmid ◽  
Toxoplasma Gondii Infection ◽  
Best Fit

ABSTRACT Infection with the protozoan parasite Toxoplasma gondiiis transmitted to humans from infected animals by tissue cysts and oocysts excreted by cats. Immunization with inactivated parasites or recombinant proteins has at best shown partial protection. We constructed a plasmid expressing the SAG1 surface antigen of T. gondii, p1tPASAG1, and showed that animals immunized with the plasmid produce anti-SAG1 antibodies which recognize the native SAG1. Mice immunized with p1tPASAG1 showed 80 to 100% protection against challenge with the non-cyst-producing, virulent RH isolate, compared to an 80% mortality in mice immunized with empty plasmid, which is the greatest efficacy of any vaccine against T. gondii produced so far. The SAG1 molecule was analyzed for potential cytotoxic T-lymphocyte (CTL) epitopes, and four peptides with the best fit were synthesized. The ability of the peptides to stimulate gamma interferon production by CD8+ T cells from p1tPASAG1-immunized mice was tested in an ELISPOT assay, and one new CTL epitope was identified. Adoptive transfer of CD8+ T cells from p1tPASAG1-immunized to naı̈ve mice showed partial protection. In conclusion, DNA vaccination with p1tPASAG1 gave effective protection in mice againstT. gondii infection and the protection could be adoptively transferred by purified CD8+ T cells.

scholarly journals Pulmonary Interleukin-17-Positive Lymphocytes Increase during Pneumocystis murina Infection but Are Not Required for Clearance of Pneumocystis

2017 ◽  
Vol 85 (7) ◽  
Author(s):  
Chiara Ripamonti ◽  
Lisa R. Bishop ◽  
Joseph A. Kovacs
Keyword(s):  
T Cells ◽  
Fungal Infections ◽  
Intracellular Cytokine Staining ◽  
Γδ T Cells ◽  
Interleukin 17 ◽  
Content Type ◽  
Immunosuppressed Patients ◽  
Ifn Γ ◽  
Immunocompetent Mice ◽  
Deficient Mice

ABSTRACT Pneumocystis remains an important pathogen of immunosuppressed patients, causing a potentially life-threatening pneumonia. Despite its medical importance, the immune responses required to control infection, including the role of interleukin-17 (IL-17), which is important in controlling other fungal infections, have not been clearly defined. Using flow cytometry and intracellular cytokine staining after stimulation with phorbol myristate acetate and ionomycin, we examined gamma interferon (IFN-γ), IL-4, IL-5, and IL-17 production by lung lymphocytes in immunocompetent C57BL/6 mice over time following infection with Pneumocystis murina. We also examined the clearance of Pneumocystis infection in IL-17A-deficient mice. The production of both IFN-γ and IL-17 by pulmonary lymphocytes increased during infection, with maximum production at approximately days 35 to 40, coinciding with peak Pneumocystis levels in the lungs, while minimal changes were seen in IL-4- and IL-5-positive cells. The proportion of cells producing IFN-γ was consistently higher than for cells producing IL-17, with peak levels of ∼25 to 30% of CD3+ T cells for the former compared to ∼15% for the latter. Both CD4+ T cells and γδ T cells produced IL-17. Administration of anti-IFN-γ antibody led to a decrease in IFN-γ-positive cells, and an increase in IL-5-positive cells, but did not impact clearance of Pneumocystis infection. Despite the increases in IL-17 production during infection, IL-17A-deficient mice cleared Pneumocystis infection with kinetics similar to C57BL/6 mice. Thus, while IL-17 production in the lungs is increased during Pneumocystis infection in immunocompetent mice, IL-17A is not required for control of Pneumocystis infection.

scholarly journals Innate, adaptive, and cell-autonomous immunity against Toxoplasma gondii infection

2019 ◽  
Vol 51 (12) ◽  
pp. 1-10 ◽  
Author(s):  
Miwa Sasai ◽  
Masahiro Yamamoto
Keyword(s):  
Immune Response ◽  
Toxoplasma Gondii ◽  
Immune Responses ◽  
Parasitophorous Vacuole ◽  
Interferon Γ ◽  
Protective Role ◽  
Ifn Γ ◽  
Acquired Immune Responses ◽  
Toxoplasma Gondii Infection ◽  
Antimicrobial Immunity

AbstractHosts have been fighting pathogens throughout the evolution of all infectious diseases. Toxoplasma gondii is one of the most common infectious agents in humans but causes only opportunistic infection in healthy individuals. Similar to antimicrobial immunity against other organisms, the immune response against T. gondii activates innate immunity and in turn induces acquired immune responses. After activation of acquired immunity, host immune cells robustly produce the proinflammatory cytokine interferon-γ (IFN-γ), which activates a set of IFN-γ-inducible proteins, including GTPases. IFN-inducible GTPases are essential for cell-autonomous immunity and are specialized for effective clearance and growth inhibition of T. gondii by accumulating in parasitophorous vacuole membranes. Recent studies suggest that the cell-autonomous immune response plays a protective role in host defense against not only T. gondii but also various intracellular bacteria. Moreover, the negative regulatory mechanisms of such strong immune responses are also important for host survival after infection. In this review, we will discuss in detail recent advances in the understanding of host defenses against T. gondii and the roles played by cell-autonomous immune responses.

scholarly journals Differential Regulation of Effector- and Central-Memory Responses to Toxoplasma gondii Infection by IL-12 Revealed by Tracking of Tgd057-Specific CD8+ T Cells

2010 ◽  
Vol 6 (3) ◽  
pp. e1000815 ◽  
Author(s):  
Douglas C. Wilson ◽  
Gijsbert M. Grotenbreg ◽  
Kenian Liu ◽  
Yanlin Zhao ◽  
Eva-Maria Frickel ◽  
...  
Keyword(s):  
T Cells ◽  
Toxoplasma Gondii ◽  
Cd8 T Cells ◽  
Differential Regulation ◽  
Central Memory ◽  
Toxoplasma Gondii Infection

scholarly journals The Level of Viral Antigen Presented by Hepatocytes Influences CD8 T-Cell Function

2007 ◽  
Vol 81 (6) ◽  
pp. 2940-2949 ◽  
Author(s):  
Adam J. Gehring ◽  
Dianxing Sun ◽  
Patrick T. F. Kennedy ◽  
Esther Nolte-'t Hoen ◽  
Seng Gee Lim ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Viral Antigen ◽  
Cell Function ◽  
Cd8 T Cell ◽  
T Cell Function ◽  
Tnf Α ◽  
Antiviral Function ◽  
Ifn Γ

ABSTRACT CD8 T cells exert their antiviral function through cytokines and lysis of infected cells. Because hepatocytes are susceptible to noncytolytic mechanisms of viral clearance, CD8 T-cell antiviral efficiency against hepatotropic viruses has been linked to their capacity to produce gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α). On the other hand, intrahepatic cytokine production triggers the recruitment of mononuclear cells, which sustain acute and chronic liver damage. Using virus-specific CD8 T cells and human hepatocytes, we analyzed the modulation of virus-specific CD8 T-cell function after recognition peptide-pulsed or virally infected hepatocytes. We observed that hepatocyte antigen presentation was generally inefficient, and the quantity of viral antigen strongly influenced CD8 T-cell antiviral function. High levels of hepatitis B virus production induced robust IFN-γ and TNF-α production in virus-specific CD8 T cells, while limiting amounts of viral antigen, both in hepatocyte-like cells and naturally infected human hepatocytes, preferentially stimulated CD8 T-cell degranulation. Our data document a mechanism where virus-specific CD8 T-cell function is influenced by the quantity of virus produced within hepatocytes.

scholarly journals KIR reconstitution is altered by T cells in the graft and correlates with clinical outcomes after unrelated donor transplantation

Blood ◽  
2005 ◽  
Vol 106 (13) ◽  
pp. 4370-4376 ◽  
Author(s):  
Sarah Cooley ◽  
Valarie McCullar ◽  
Rosanna Wangen ◽  
Tracy L. Bergemann ◽  
Stephen Spellman ◽  
...  
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Clinical Outcomes ◽  
Hematopoietic Cell Transplantation ◽  
Cell Function ◽  
Nk Cell ◽  
Interferon Γ ◽  
Unrelated Donor ◽  
Ifn Γ

Although unrelated hematopoietic cell transplantation (HCT) is curative for many hematologic malignancies, complications and relapse remain challenging obstacles. Natural killer (NK) cells, which recover quickly after transplantation, produce cytokines and express killer immunoglobulin-like receptors (KIRs) that regulate their cytotoxicity. Some clinical trials based on a KIR ligand mismatch strategy are associated with less relapse and increased survival, but results are mixed. We hypothesized that T cells in the graft may affect NK cell function and KIR expression after unrelated transplantation and that these differences correlate with clinical outcomes. NK cell function was evaluated using 77 paired samples from the National Marrow Donor Program Research Repository. Recipient NK cells at 100 days after both unmanipulated bone marrow (UBM) and T-cell depleted (TCD) transplants were compared with NK cells from their healthy donors. NK cells expressed fewer KIRs and produced more interferon γ (IFN-γ) after UBM compared to TCD transplants. Multivariate models showed that increased NK cell IFN-γ production correlated with more acute graft-versus-host disease (GVHD), and decreased KIR expression correlated with inferior survival. These results support the notion that T cells in the graft affect NK cell reconstitution in vivo. Understanding these mechanisms may result in strategies to improve clinical outcomes from unrelated HCT.

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