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Cynthia A. Cordeiro, Erica L. Vieira, Vinicius M. Castro, Walderez O. Dutra, Juliana L. Orefice, Rogerio A. Costa, Wesley R. Campos, Fernando Orefice, Antonio L. Teixeira, Lucy H. Young; T Cell Immunoregulation In Active Ocular Toxoplasmosis. Invest. Ophthalmol. Vis. Sci. 2012;53(14):1190.
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© ARVO (1962-2015); The Authors (2016-present)
Toxoplasma gondii infection is an important cause of ocular disease in both immunocompromised and immunocompetent subjects. The pathogenesis of retinochoroidal lesion associated with this infection is not fully understood. The present study was undertaken to investigate cellular proliferation and cytokine expression by peripheral blood mononuclear cells (PBMC) from individuals with active toxoplasmic retinochoroiditis (TR) comparing with controls.
Eighteen patients with diagnosed active TR were recruited from the Uveitis Section, Department of Ophthalmology, Universidade Federal de Minas Gerais - Brazil, between August 2010 and January 2011. Fifteen healthy controls matched by age and gender were included as controls. Six had positive IgG antibody for Toxoplasmosis without any history of uveitis and nine had negative IgG antibody for Toxoplasmosis. All controls were submitted to fundoscopy to exclude the presence of retinal scars. Blood samples were collected before any treatment. PBMC were obtained, incubated in the presence or absence of T. gondii soluble tachyzoites antigen (STAg) and stained with labeled antibodies directed against surface molecules (CD4 and CD8) and cytokines (TNF-α, IL-10, IFN-γ). Preparations were analyzed on FACSCan selecting the lymphocyte population. A minimum of 30,000 gated events from each sample were acquired and analyzed using the FlowJo 7.6.5 software.
Without STAg stimulation, there was no difference in cytokine expression between controls and patients with TR. Following STAg stimulation, the controls did not show any change in cytokine expression. However, patients with TR showed an increased IFN-γ expression by total lymphocytes, CD4 and CD8 cells, increased TNF-α by total lymphocytes and CD4 cells and elevated IL-10 by CD4 cells after stimulation with STAg. When compared with controls, after stimulation with STAg, there was increased IFN-γ, TNF-α and IL-10 expression by total lymphocytes in patients comparing with controls. As to CD4 and CD8 cells, there was only an increase in IL-10 expression.
This study demonstrates that the response to toxoplasma antigen is observed only in patients with active TR. Results also suggest that the occurrence of TR may be related with the balance of CD4 and CD8 cells cytokine expression.
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