Invest Ophthalmol Vis Sci. 2010 Sep 1. [Epub ahead of print]
CXCL10 is required to maintain T cell populations and control parasite replication during chronic ocular toxoplasmosis
Norose K, Kikumura A, Luster AD, Hunter CA, Harris TH.
Infection and Host Defense, Chiba University, Chiba, Japan.
PURPOSE. Toxoplasma gondii is a major cause of ocular disease, which can lead to permanent vision loss in humans. T cells are critically involved in parasite control, but little is known about the molecules that promote T cell trafficking and migration in the retina. Thus, the aim of this study was to image and dissect the T cell response during chronic toxoplasmic retinochoroiditis. METHODS. C57BL/6 mice were infected with the Me49 strain of T. gondii and T cells that infiltrated the eye were analyzed by flow cytometry and imaged using multi-photon microscopy. IFN-gamma, CXCL9, CXCL10, and CXCR3 mRNA levels were measured by real-time PCR. To investigate the role of CXCL10, mice were treated with anti-CXCL10 antibodies and histopathology and immunohistochemistry were performed to monitor changes in pathology, cellular infiltration, and parasite burden in the eye. RESULTS. Infection with T. gondii leads to the infiltration of highly-activated, motile T cells into the eye. These cells express CXCR3, are capable of producing IFN-gamma and TNF-alpha, and CD8+ T cells express granzyme B. The expression of CXCL9 and CXCL10 in the retina was significantly upregulated during chronic infection. Treatment of chronically infected mice with anti-CXCL10 antibodies led to decreases in the number of CD3+, CD4+, and CD8+ T cells and IFN-gamma mRNA expression in the retina and an increase in replicating parasites and ocular pathology. CONCLUSION. The maintenance of the T cell response and control of T. gondii in the eye during chronic infection is dependent on CXCL10.
PMID: 20811054 [PubMed - as supplied by publisher]