http://www.eeb.cornell.edu/harvell/Site/%3C2005_files/Alker04.pdf

Coral Reefs (2004) 23: 397–405 published July 2004

by  Alisa P. Alker, Kiho Kim, Danielle H. Dube, C. Drew Harvell

This study, based on studies in the Florida Keys supported by Reef Relief, finds that sea fans exhibit a purpling response to biotic agents that reduces subsequent damage to the tissue.   There was speculation that this knowledge could be applied to help humans fight disease.