FUNCTION AND CELL-SURFACE PHENOTYPE OF DENDRITIC CELLS FROM RAT CORNEA

Purpose, To isolate dendritic cells (DC) from rat corneas and to exami ne their functions and surface markers in vitro. Methods, Cells were i solated enzymatically from dissected rat corneas and cultured for vari ous intervals of time. Dendritic cells were enriched immunomagneticall y from corneal cell preparations using monoclonal antibodies against D C surface antigens and tested for functional activity in lymphocyte st imulation assays. In vivo migration of DC was induced by traumatizing the corneal epithelium. Wholemounts of epithelial sheets were stained immunofluorescently with anti-DC antibodies and examined by confocal m icroscopy. Dendritic cells isolated from traumatized corneas were test ed for functional activity. Results, Corneal DC exhibited the properti es of other members of the DC family, i.e., low buoyant density, lymph oid DC-specific markers, and lymphostimulatory function. In fresh unfr actionated cell preparations of normal cornea, no functional activity was detected. However, DC immunomagnetically purified from fresh prepa rations were functionally active. Injury to the corneal epithelium ind uced the migration of DC from the periphery to the central cornea; DC measured in this situation showed significantly increased functional a ctivity. Finally, IL-1 beta and GM-CSF enhanced the functional activit y of corneal DC. Conclusions, Corneal DC have lymphostimulatory capaci ty in situ, but they may be maintained in a state of latency by the su ppressive influence exerted by neighboring cells. Injury to the cornea l epithelium results in functional activation of the corneal DC, which may be caused by cytokines such as IL-1 beta or GM-CSF. Thus, corneal DC may be important in the immune regulation of the anterior segment.