Macrophage responses to Toxoplasma antigens in vitro: a possible role in inflammatory lesions in toxoplasmosis.

Tackey, Robert; Kassim, Olakunle O.

doi:10.4269/ajtmh.1999.61.272

Cited by 2 publications

(1 citation statement)

References 43 publications

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“…Assuming that some of these target macrophages are infected with parasites, V␥1 ϩ cells are likely to play a central and important role in Toxoplasma containment because macrophages are major cellular targets for Toxoplasma infection and dissemination in peripheral tissues (this study) (64) and their elimination would be an effective means of controlling parasite infection. In particular, the unresolved inflammation and increased parasite cyst burden in the brain of infected TCR-␦ Ϫ/Ϫ and V␥1 Ϫ/Ϫ mice suggest that V␥1 ϩ T cells can contribute to resolving inflammation in the brain of T. gondii-infected mice by killing activated macrophages that make up a large part of the CNS infiltrate (this study) (65) and can contribute to the development of inflammatory lesions (66). In particular, they may help prevent or limit the extent of CNS inflammation by eliminating macrophages that during the acute phase are infected with cyst-forming bradyzoites (65) and can serve as a kind of "Trojan horse" and transport mechanism for entry of parasite into the brain (64).…”

Section: Discussionmentioning

confidence: 99%

A Requirement for the Vγ1+ Subset of Peripheral γδ T Cells in the Control of the Systemic Growth of Toxoplasma gondii and Infection-Induced Pathology

Egan

Dalton

Andrew

et al. 2005

The Journal of Immunology

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γδ T cells are a diverse population of T cells that are widely distributed and are a common feature of pathogen-induced immune responses. It is not clear, however, whether different populations of γδ T cells have specific functions, and what factors determine the functional properties of individual populations. A murine model of peroral Toxoplasma gondii infection was used to determine the contribution Vγ1+ intestinal intraepithelial lymphocytes (IELs) vs systemic Vγ1+ T cells make to the acute and chronic stages of the host immune response, and whether the macrophage cytocidal activity of Vγ1+ T cells described in bacterial infections is seen in other, unrelated infectious disease models. In response to oral infection with virulent type 1 or avirulent type II strains of T. gondii, TCR-δ−/− mice rapidly developed severe ileitis. In contrast, in mice deficient in Vγ1+ T cells and IELs and wild-type mice, inflammation was delayed in onset and less severe. The protective effect of (Vγ1−) IELs to Toxoplasma infection was unrelated to their cytolytic and cytokine (Th1)-producing capabilities. Systemic Vγ1+ T cells were shown to play an essential role in limiting parasite growth and inflammation in peripheral tissues and, in particular, in the CNS, that was associated with their ability to efficiently kill parasite-elicited and infected macrophages. These findings suggest that macrophage cytocidal activity of Vγ1+ T cells may be a universal feature of pathogen-induced immune responses and that microenvironmental factors influence the involvement and function of γδ T cells in the host response to infection.

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