Decreased ecto-5'-nucleotidase activity in rabbit lymphocytes during experimental lens-induced uveitis

An experimental uveitis was produced by immunizing albino and pigmented rabbits with heterologous (rat) lens protein six times at two-week intervals. After sensitization the anterior lens capsules were disrupted in an operation. After operation the rabbits were examined repeatedly with a slit-lamp. On the seventh day after operation the animals were sacrificed and both eyes were enucleated. The inflammatory reaction in the uveal tract was verified histopathologically. Thymus and spleen lymphocytes were purified using BSA-gradients. Ecto-5'-nucleotidase (AMP-ase) activity on the intact lymphocytes was measured biochemically and B-cells were counted using the fluorescent anti-IgG technique. Purified spleen and thymus lymphocytes were also analyzed using transmission electron microscopy. The AMP-ase activity of purified spleen lymphocytes was significantly decreased in albino rabbits suffering from experimental lens-induced uveitis when compared to that observed in control animals. The AMP-ase activity was also decreased in pigmented rabbits suffering from a very mild uveitis. Moreover, a decreased AMP-ase activity was observed in albino rabbits which were only immunized but not operated on and did not show any signs of uveitis. Differences in neither the B-cell proportions nor the ultrastructure of the purified lymphocytes could be observed in any of these experimental groups. It is proposed that the biochemical change in spleen lymphocytes observed in the present work is a reflection of the general immunological state which in certain conditions may lead to uveitis.