Infiltration of CD4+ T Cells into Cornea during Development of Onchocerca volvulus-Induced Experimental Sclerosing Keratitis in Mice

Abstract Sclerosing keratitis is the major cause of blindness due to onchocerciasis caused by the parasite Onchocerca volvulus . Although the importance of T cells in the pathogenesis of onchocerciasis has been suggested, their precise role in onchocercal sclerosing keratitis has not yet been defined. Using immunohistological techniques and a murine model of onchocercal sclerosing keratitis, we have performed a temporal analysis of the inflammatory T cells infiltrating into the cornea at Days 4, 7, and 21 following intrastromal challenge with soluble O. volvulus antigens into presensitized mice. The maximum number of CD3 + T cells were observed in the corneal stroma at Day 21 when sclerosing keratitis was most severe. The majority (>85%) of the CD3 + T cells were CD4 + at all time points. A few infiltrating cells bore IL-2 receptors indicating possible activation of a small fraction of the T cells. These results suggest that CD4 + T cells play an important role in onchocercal sclerosing keratitis.