Abstract
Purpose: :
Autoimmune lymphocyte-proliferations were shown in blood of patients with normal pressure glaucoma (NPG). In previous studies systemic immunization with ocular antigens like optic nerve homogenate (ONA) led to an immune-mediated retinal ganglion cell (RGC) loss in rodents.
Methods: :
Rats were immunized with antigens (ONA, S100) in Freund's Adjuvants (FA) and Pertussis Toxin (PTx). S100 belongs to a neural, low weight protein family with a calcium binding side. Both groups were compared to NaCl-controls (Co). The intraocular pressure (IOP) was measured for four weeks. After 28 days the RGC density of six eys per group was quantified using cresyl stained retinal flatmounts and six cryo-sectioned eyes were fluorescence stained with Brn3a-antibody (Santa Cruz). CD3-FITC/CD45R-PE ratio (both eBioscience) were analyzed in spleen, cervical lymph nodes, blood and retina (n=5 per group) using a Cyflow-FACS (Partec) after 14 days. Groups were compared with student t-test.
Results: :
No significant changes in the IOP of S100 (p=0.3) and ONA group (p=0.5) in correlation to Co rats were measured. In contrast to the Co group a significant RGC loss in both groups could be investigate (S100: p=0.005; ONA: p=0.0005). A little population of CD3+-cells (~6%) and almost no CD45R+-cells migrated in the retina of S100 and ONA animals after 14 days. The alteration of CD3/CD45R-ratio seems antigen dependent in the immunized groups in the different organs.
Conclusions: :
Immunization with ONA and S100 led to a RGC-loss without changes in IOP in this autoimmune model. The T-cells likely overcame the blood-retina-barrier after immunization, while the B-cells proliferated and stayed systemically. Autoimmune T-cells seem to play an important role in the course of RGC death. It is unknown, if T-cells participate in the first degeneration period or follow a chemotaxis signal and trigger a second degeneration.
Keywords: immunomodulation/immunoregulation • flow cytometry • ganglion cells