Parasitized Natural Killer cells do not facilitate the spread of <i>Toxoplasma gondii</i> to the brain

Petit-Jentreau, Laetitia; Glover, Catherine; Coombes, Janine L.

doi:10.1111/pim.12522

Cited by 6 publications

(6 citation statements)

References 38 publications

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“…[147][148][149] It has been shown, however, that parasite-infected NK cells were defective for host defense. 150 Furthermore, it is uncertain if NK cell IFNγ is actually beneficial during infection, as it was reported that antibody-mediated NK cell depletion did not affect the survival of T. gondii-infected mice. 151 Interestingly, ILC1s represent a primary IFNγ-secreting population during acute infection with T. gondii.…”

Section: Intracellular Pathogensmentioning

confidence: 99%

The role of innate lymphoid cells in response to microbes at mucosal surfaces

2020

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Innate lymphoid cells (ILCs) are a lymphocyte population that is mostly resident at mucosal surfaces. They help to induce an appropriate immune response to the microbiome at homeostasis. In healthy people, the mucosal immune system works symbiotically with organisms that make up the microbiota. ILCs play a critical role in orchestrating this balance, as they can both influence and in turn be influenced by the microbiome. ILCs also are important regulators of the early response to infections by diverse types of pathogenic microbes at mucosal barriers. Their rapid responses initiate inflammatory programs, production of antimicrobial products and repair processes. This review will focus on the role of ILCs in response to the microbiota and to microbial infections of the lung and intestine.

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Section: Intracellular Pathogensmentioning

confidence: 99%

The role of innate lymphoid cells in response to microbes at mucosal surfaces

2020

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“…A small number of studies have investigated whether parasite infection of NK cells affects their behavior (47–49). NK cells can be parasitized, however, this occurs at a very low frequency in vitro and in vivo .…”

Section: Ilc and Toxoplasma Gondiimentioning

confidence: 99%

“…These infected NK cells display a hypermotility phenotype and defective function. A recent study indicates that infected NK cells do not contribute to parasite dissemination in the mouse (47). Thus, how direct parasite infection of NK cells impacts the disease course is not known and needs to be further explored.…”

Section: Ilc and Toxoplasma Gondiimentioning

confidence: 99%

Innate Lymphoid Cells in Protection, Pathology, and Adaptive Immunity During Apicomplexan Infection

et al. 2019

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Apicomplexans are a diverse and complex group of protozoan pathogens including Toxoplasma gondii, Plasmodium spp., Cryptosporidium spp., Eimeria spp., and Babesia spp. They infect a wide variety of hosts and are a major health threat to humans and other animals. Innate immunity provides early control and also regulates the development of adaptive immune responses important for controlling these pathogens. Innate immune responses also contribute to immunopathology associated with these infections. Natural killer (NK) cells have been for a long time known to be potent first line effector cells in helping control protozoan infection. They provide control by producing IL-12 dependent IFNγ and killing infected cells and parasites via their cytotoxic response. Results from more recent studies indicate that NK cells could provide additional effector functions such as IL-10 and IL-17 and might have diverse roles in immunity to these pathogens. These early studies based their conclusions on the identification of NK cells to be CD3–, CD49b+, NK1.1+, and/or NKp46+ and the common accepted paradigm at that time that NK cells were one of the only lymphoid derived innate immune cells present. New discoveries have lead to major advances in understanding that NK cells are only one of several populations of innate immune cells of lymphoid origin. Common lymphoid progenitor derived innate immune cells are now known as innate lymphoid cells (ILC) and comprise three different groups, group 1, group 2, and group 3 ILC. They are a functionally heterogeneous and plastic cell population and are important effector cells in disease and tissue homeostasis. Very little is known about each of these different types of ILCs in parasitic infection. Therefore, we will review what is known about NK cells in innate immune responses during different protozoan infections. We will discuss what immune responses attributed to NK cells might be reconsidered as ILC1, 2, or 3 population responses. We will then discuss how different ILCs may impact immunopathology and adaptive immune responses to these parasites.

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“…However, the consequences of this phenotype for dissemination of T. gondii into the brain remain unknown. Similarly, a mouse study found no evidence for a role for hypermotile NK cells in delivery of parasites to the brain during acute infection with T. gondii (Petit-Jentreau et al, 2018). In order to disseminate effectively within host cells many intracellular pathogens first infect leukocytes, which they use as a vehicle to transport them to target organs.…”

Section: Immune-mediated Control Of T Gondiimentioning

confidence: 99%

Toxoplasma gondii: Deeper understanding of epidemiology, virulence and pathophysiology enhances diagnosis and informs vaccine design

Woyesa¹,

Taylor‐Robinson²

2021

J. Infect. Dis. Immun.

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Toxoplasma gondii is an extremely widespread intracellular obligate parasite that infects both animals and birds. This protozoan pathogen usually causes asymptomatic infection in humans but can cause significant disease in congenitally infected infants, immunodeficient patients and occasionally in immunocompetent individuals. In the complex life cycle of T. gondii, sexual development occurs uniquely in felines whereas asexual reproduction may take place in humans and other warm-blooded animals serving as intermediate hosts. The prevalence of infection varies considerably among different geographic areas and also among individuals, depending on a variety of factors, including culinary habits and cleanliness of surroundings. Studies to date show low genetic diversity of T. gondii, with three main lineages, designated types I, II and III, found at least within Europe and North America. T. gondii uses various mechanisms to invade host cells and to alter their signal pathways and gene expression. Kinases within the rhoptry, a unique apical organelle, and T. gondii granule proteins are key virulence factors that promote attachment to, and invasion of, host cells. Human Toxoplasma infection is acquired by ingestion of raw or undercooked meat that contains tissue cysts, or through the ingestion of water or food contaminated with oocysts. It is also transmitted congenitally from motherto-foetus and less commonly by transfusion of contaminated blood or transplantation of an infected organ. Life-threatening toxoplasmosis can develop in immunocompromised patients. Diagnostic tests are critical to surveillance, control and prevention of toxoplasmosis. However, different technologies presently utilized around the world to detect different parasite stages are not of a uniformly sufficient standard to indicate clearly the epidemiology and severity of infection at global, regional and national levels. While a prophylactic vaccine is licensed for veterinary administration, no similarly efficacious preparation is available to prevent human infections. Here, we review the epidemiology and genotypes of T. gondii, as well as current detection methods and the state of vaccine development. In addition, the mechanisms by which this parasitic pathogen invades and overcomes the human immune system are considered.

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Parasitized Natural Killer cells do not facilitate the spread of Toxoplasma gondii to the brain

Cited by 6 publications

References 38 publications

The role of innate lymphoid cells in response to microbes at mucosal surfaces

The role of innate lymphoid cells in response to microbes at mucosal surfaces

Innate Lymphoid Cells in Protection, Pathology, and Adaptive Immunity During Apicomplexan Infection

Toxoplasma gondii: Deeper understanding of epidemiology, virulence and pathophysiology enhances diagnosis and informs vaccine design

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