B Cells Are Essential for Vaccination-Induced Resistance to Virulent<i>Toxoplasma gondii</i>

Sayles, Peter C.; Gibson, George W.; Johnson, Lawrence L.

doi:10.1128/iai.68.3.1026-1033.2000

Cited by 186 publications

(143 citation statements)

References 36 publications

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“…Thus, there is a remarkable loss of T cells in chronically infected NF-B 2 Ϫ/Ϫ mice which correlates with a reduced capacity to produce IFN-␥ and susceptibility to TE. In addition, it is noteworthy that while uninfected NF-B 2 Ϫ/Ϫ mice have reduced numbers of B cells compared with WT mice (20,21) there was a further reduction in this population of cells during the chronic stage of infection and this may contribute to the increased susceptibility of these mice to TE (46,47). Nevertheless, like the patients with AIDS, certain cancers, or who are being treated with immunosuppressive drug regimens (23,24,48), the remarkable loss of lymphocytes and/or lymphocyte functions in chronically infected NF-B 2 Ϫ/Ϫ mice provides a mechanism that underlies the development of TE in these mice.…”

Section: Discussionmentioning

confidence: 99%

Identification of a Role for NF-κB2 in the Regulation of Apoptosis and in Maintenance of T Cell-Mediated Immunity toToxoplasma gondii

Caamaño

Tato

Cai

et al. 2000

The Journal of Immunology

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The NF-κB family of transcription factors are involved in the regulation of innate and adaptive immune functions associated with resistance to infection. To assess the role of NF-κB2 in the regulation of cell-mediated immunity, mice deficient in the NF-κB2 gene (NF-κB2−/−) were challenged with the intracellular parasite Toxoplasma gondii. Resistance to this opportunistic pathogen is dependent on the production of IL-12, which is required for the development of innate NK cell and adaptive T cell responses dominated by the production of IFN-γ necessary to control replication of this parasite. Although wild-type controls were resistant to T. gondii, NF-κB2−/− mice developed severe toxoplasmic encephalitis and succumbed to disease between 3 and 10 wk following infection. However, NF-κB2 was not required for the ability of macrophages to produce IL-12 or to inhibit parasite replication and during the acute stage of infection, NF-κB2−/− mice had no defect in their ability to produce IL-12 or IFN-γ and infection-induced NK cell responses appeared normal. In contrast, during the chronic phase of the infection, susceptibility of NF-κB2−/− mice to toxoplasmic encephalitis was associated with a reduced capacity of their splenocytes to produce IFN-γ associated with a loss of CD4+ and CD8+ T cells. This loss of T cells correlated with increased levels of apoptosis and with elevated expression of the pro-apoptotic molecule Fas by T cells from infected NF-κB2−/− mice. Together, these results suggest a role for NF-κB2 in the regulation of lymphocyte apoptosis and a unique role for this transcription factor in maintenance of T cell responses required for long-term resistance to T. gondii.

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Section: Discussionmentioning

confidence: 99%

Identification of a Role for NF-κB2 in the Regulation of Apoptosis and in Maintenance of T Cell-Mediated Immunity toToxoplasma gondii

Caamaño

Tato

Cai

et al. 2000

The Journal of Immunology

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“…Rats are considered as animal model for Toxoplasma gondii infection (Dubey, 1988). The parasite develops adaptive humeral and cell-mediated immune responses following a primary infection in cats, sheep and human (Innes and Vermeulen, 2006), the immunological response against T. gondii antigen clearly a strong cytotoxic T cell response (Sayles et al, 2000;Johnson et al, 2004). As T. gondii is an obligate intracellular parasite, cellular immunity has been considered the major response to eliminate the parasite within the host, yet humoral immunity also plays an important role in shaping the immune responses (El Fadaly et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Egyptian Propolis 12: Influence of Propolis on Cytokines of Toxoplasma gondii Infected Rats

Hegazı¹,

Guthami²,

Gethami³

et al. 2017

Int.J.Curr.Microbiol.App.Sci

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“…16,35 Moreover, humoral immune response resulting in IgG antibodies seems to be necessary for preventing and controlling T. gondii infection. 36 This is because specific antibodies can inhibit the attachment of the parasites to host cells, as well as promote macrophages to kill antibody-coated parasites. 36 As far as the evaluation of protective potency of T. gondii exosomes was concerned, the inbred BALB/c mice were challenged intraperitoneally with 1×10 3 tachyzoites of T. gondii RH strain (Type I) and ME 49 strain (Type II).…”

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confidence: 99%

Characterization of exosomes derived from <em>Toxoplasma gondii</em> and their functions in modulating immune responses

Li¹,

Liu²,

Xiu³

et al. 2018

IJN

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Introduction Exosomes are nanograde membrane-bound vesicles secreted from most cell types through the fusion of multivesicular bodies with plasma membranes. Some of these exosomes are well defined, and are known to have immunomodulatory properties as well as play critical roles in intercellular communications. In this study, we characterized the exosomes derived from Toxoplasma gondii and their functions in aspect of immune responses. Methods T. gondii exosomes were isolated and identified using electron microscopy, nanoparticle tracking analysis, and Western blotting. The viability of macrophage RAW264.7 cells affected by exosomes was evaluated using a Cell Counting Kit (CCK-8). Then the uptake of T. gondii exosomes by RAW264.7 cells was detected by labeling with fluorescent dye PKH67. After exosomes stimulation, in vitro the production of interleukin (IL)-12, tumor necrosis factor (TNF)-α, interferon (IFN)-γ and IL-10 in RAW264.7 cells were investigated using enzyme-linked immunosorbent assay (ELISA). In immunized BALB/c mice, the antibodies, cytokines as well as the percentage of CD4+ and CD8+ T cells were determined using ELISA and flow cytometric analysis. Protective efficacy was evaluated by challenging intraperitoneally with tachyzoites of T. gondii . Results We successfully isolated and characterized the exosomes derived from T. gondii . Functionally, the viability of macrophage RAW264.7 cells was significantly affected by exosomes at a high concentration (160 μg/mL). The production of IL-12, TNF-α and IFN-γ in macrophage cells were increased, and the level of IL-10 was decreased. Furthermore, BALB/c mice immunized with T. gondii exosomes showed both humoral and cellular immune responses and also exhibited a prolonged survival time. Conclusion T. gondii exosomes could modulate macrophage activation in vitro and trigger humoral and cellular immune responses and partial protection against acute parasite infection in mice, which suggested that exosomes may serve as a potential candidate against toxoplasmosis.

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B Cells Are Essential for Vaccination-Induced Resistance to VirulentToxoplasma gondii

Abstract: T lymphocytes and gamma interferon (IFN-␥

Cited by 186 publications

References 36 publications

Identification of a Role for NF-κB2 in the Regulation of Apoptosis and in Maintenance of T Cell-Mediated Immunity toToxoplasma gondii

Identification of a Role for NF-κB2 in the Regulation of Apoptosis and in Maintenance of T Cell-Mediated Immunity toToxoplasma gondii

Egyptian Propolis 12: Influence of Propolis on Cytokines of Toxoplasma gondii Infected Rats

Characterization of exosomes derived from <em>Toxoplasma gondii</em> and their functions in modulating immune responses

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