97th DOG Annual Meeting 1999



T. T. Luther, N. Kociok, A. Hueber, S. Grisanti, U. Schraermeyer, P. J. Esser

Defensins are a small group of cationic peptids with a broad spectrum of antibiotic activity. They play an important role in innate nonadaptive immunity. Originally found in alveolar macrophages, they are now described in different muco-epithelial surfaces of the human body. Their antimicrobial activity is directed against bacteria, fungi and some virus species. There is physiological and potentially pathogenetic interest, weather defensins are involved in host defense mechanisms in the immunoprivileged inner part of the eye.

Methods: Fresh human retinal pigmentepithelial cells (RPE) and RPE cells from later passages in culture were studied with regard to their expression of defensins. In order to specifically detect a-defensin 1-6 and b-defensin 1-2, specific primers were synthesized. RT-PCR was performed with fresh mRNA of RPE cells and defensin expression was compared with glyceraldehyd-3-phosphat-dehydrogenase (GADPH) and ß2-microglobulin. PCR products were sequenced to ensure specifity of the PCR reaction.

Results: At the RNA-level several members of defensins were detected. Both in RPE cells freshly prepared from the eye as well as in cultured RPE cells defensin-mRNA could be found. The level of expression varied either from type of defensin studied or between fresh and cultured RPE cells. In particular presence of a-defensin 1-5 and b-defensin 1-2 could be shown in fresh and cultured RPE cells.

Discussion: This study was able to demonstrate physiological expression of defensins in RPE cells. The role of defensins in host defense mechanisms such as endophthalmitis and other intraocular infections is currently under investigation.

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