Abstract
Abstract: :
Purpose: The incidence of primary intraocular lymphomas has tripled in the past decade. Currently, the only available model is a murine metastatic malignant lymphoma that occurs following intraperitoneal inoculation of Rev–2–T–6 cells, a T–cell lymphoma of Balb/c origin. We report here the utilization of these cells to develop a model for primary intraocular lymphoma. Methods: Using a 30 gauge Hamilton syringe, Rev–2–T–6 cells in 3 micro liter PBS were injected through the pars plana into the left vitreous of 6–8 weeks old Balb/c mice. Eight mice were injected with 0.5 x 105 cells and 8 were injected with 1.0 x 105 cells. Mice were monitored clinically every other day and under fundoscopic examination weekly. According to clinical manifestations, mice were euthanized on week 3, 5, or 6 post inoculation. The second experiment included 12 mice inoculated with 1.0 x 105 cells and euthanized 7 or 8 weeks later. All eyes were processed for histology. Immunohistochemistry was performed with a specific antibody (JP14) against the Rev–2–T–6 cells using immunoperoxidase technique. Results: Vitreous haze and retinal lesions appeared in 3/16 mice (two received 1.0 x 105 cells and one received 0.5 x 105 cells) one–week post inoculation. By the 3rd week, marked vitreous opacity was observed clinically in 7/8 mice that received 1.0 x 105 and 4/8 mice that received 0.5 x 105 Rev–2–T–6 cells. Histology confirmed 7/8 mice of the 1.0 x 105 cells injected group and 6/8 mice of the 0.5 x 105 cells injected group were positive for intraocular lymphoma in the vitreous and/or subretinal space. Rare lymphoma cells were found in the retina. Only 2/16 mice showed lymphoma infiltration into the choroid. Tumor localization was confirmed by immunohistochemistry. This suggests that RPE cells constitute a barrier for intraocular lymphoma spread. The right eyes and both optic nerves were free of tumor in all mice. The second experiment presented similar results with decreased incidence and severity of disease. Conclusions: Intravitreal injection of Rev–2–T–6 cells is a novel model for primary intraocular lymphoma in immune competent hosts. This model will aid in understanding the molecular mechanisms, as well as the role of RPE cells in lymphoma invasion.
Keywords: tumors • pathology: experimental • injection