Human immunodeficiency virus type 1 (HIV) infection of the central nervous system is characterized by neuronal loss in discrete areas of the central nervous system. We have previously demonstrated that HIV-infected monocytes in culture with astroglial cells produce high levels (≧ 200 pg/ml) of the cytokine tumor necrosis factor-alpha (TNFα). We now demonstrate that TNFα (≧ 200 pg/ml) is neurotoxic to cultured primary human fetal cortical neurons at both light and electron microscopic levels. Subtoxic doses of TNFα (50 pg/ml) are neurotoxic in combination with the glutamate (±)-α-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid (AMPA) subtype receptor agonist AMPA (100 µM). The neurotoxic effects of TNFα (200 pg/ml) are blocked in part by the AMPA receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (10 µM). This suggests that TNFα may exert neurotoxic effects on human neurons by indirect activation of AMPA receptors, which may be important in the pathogenesis and treatment of HlV-mediated encephalopathy.

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Although it is surgically feasible to transplant fetal RPE to the subretinal space of patients with GA, such an allogenic RPE transplant without immunosuppression leads to leakage on fluorescein angiography and eventual fibrosis. A very weak immune response against proteins associated with photoreceptors is also of concern.

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\s=b\The morphologic status of corneal innervation was studied in rats with strep-