Histochem Cell Biol DOI 10.1007/s00418-010-0713-y 123 ORIGINAL PAPER Roles of human -defensins in innate immune defense at the ocular surface: arming and alarming corneal and conjunctival epithelial cells Fabian Garreis · Thomas Schlorf · Dieter Worlitzsch · Philipp Steven · Lars Bräuer · Kristin Jäger · Friedrich P. Paulsen Accepted: 18 May 2010  Springer-Verlag 2010 Abstract Human -defensins are cationic peptides pro- duced by epithelial cells that have been proposed to be an important component of immune function at mucosal sur- faces. In this study, the expression and inducibility of -defensins at the ocular surface were investigated in vitro and in vivo. Expression of human -defensins (hBD) was determined by RT-PCR and immunohistochemistry in tis- sues of the ocular surface and lacrimal apparatus. Cultured corneal and conjunctival epithelial cells were stimulated with proinXammatory cytokines and supernatants of diVer- ent ocular pathogens. Real-time PCR and ELISA experi- ments were performed to study the eVect on the inducibility of hBD2 and 3. Expression and inducibility of mouse -defensins-2, -3 and -4 (mBD2–4) were tested in a mouse ocular surface scratch model with and without treatment of supernatants of a clinical Staphylococcus aureus (SA) iso- late by means of immunohistochemistry. Here we show that hBD1, -2, -3 and -4 are constitutively expressed in con- junctival epithelial cells and also partly in cornea. Healthy tissues of the ocular surface, lacrimal apparatus and human tears contain measurable amounts of hBD2 and -3, with highest concentrations in cornea and much lower concen- trations in all other tissues, especially tears, suggesting intraepithelial storage of -defensins. Exposure of cultured human corneal and conjunctival epithelial cells to proin- Xammatory cytokines and supernatants of various bacteria revealed that IL-1 is a very strong inductor of hBD2 and Staphylococcus aureus increases both hBD2 and hBD3 production in corneal and conjunctival epithelial cells. A murine corneal scratch model demonstrated that -defen- sins are only induced if microbial products within the tear Wlm come into contact with a defective epithelium. Our Wnding suggests that the tear Wlm per se contains so much antimicrobial substances that epithelial induction of -defensins occurs only as a result of ocular surface damage. These Wndings widen our knowledge of the distribution, amount and inducibility of -defensins at the ocular surface and lacrimal apparatus and show how -defensins are regu- lated speciWcally. Keywords Human -defensins · Mouse -defensins · Ocular surface · Staphylococcus aureus · ProinXammatory cytokines Abbreviations HCE Human corneal epithelial cells HCjE Human conjunctival epithelial cells IL Interleukin TNF Tumor necrosis factor F. Garreis · T. Schlorf · L. Bräuer · K. Jäger · F. P. Paulsen Department of Anatomy and Cell Biology, Martin Luther University of Halle-Wittenberg, Große Steinstraße 52, 06108 Halle (Saale), Germany D. Worlitzsch Department of Hygiene, Martin Luther University of Halle-Wittenberg, Große Steinstraße 52, 06108 Halle (Saale), Germany P. Steven Department of Ophthalmology, University Medical Center Schleswig-Holstein, Campus Lübeck, Ratzeburger Allee 160, 23538 Lübeck, Germany F. Garreis (&) · F. P. Paulsen (&) Department of Anatomy II, Friedrich Alexander University Erlangen-Nürnberg, Universitätsst. 19, 91054 Erlangen, Germany e-mail: fabian.garreis@anatomie2.med.uni-erlangen.de F. P. Paulsen e-mail: friedrich.paulsen@anatomie2.med.uni-erlangen.de