NGF involvement in ocular inflammation: secretion by rat resident retinal cells

Nerve growth factor (NGF) has been reported to be involved in immune and inflammatory reactions. We provide evidence that NGF may play a role in ocular immune responses. Experimental autoimmune uveoretinitis (EAU) causes ocular inflammation in susceptible (Lewis, Lew x Brown-Norway (BN) F1 hybrid) but not in resistant or poorly susceptible BN and Long Evans rat strains. We examined NGF production by two resident ocular cell types, retinal Müller glia (RMG) and retinal pigmented epithelium (RPE). Interferon-gamma (IFN-gamma) or lipopolysaccharide (LPS) alone had no effect on NGF production while combined treatment with IFN-gamma and LPS strongly stimulated NGF secretion by both RMG and RPE cells. Furthermore, NGF secretion correlated with the degree of susceptibility to EAU of the different rat strains. RMG and RPE cells isolated from susceptible rats secrete high NGF levels while cells from resistant rats secrete low NGF levels.