Submitted to: American Fisheries Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: June 15, 2005
Publication Date: September 11, 2005
Citation: Xu, D., Klesius, P.H., Shoemaker, C.A. 2005. Cutaneous antibodies from catfish immune to Ichthyophthirius (Ich) induced apoptosis of Ich theronts. American Fisheries Society Annual Meeting. Page 386. Technical Abstract: This study explored the existence of apoptosis (programmed cell death) in fish parasitic protozoan Ichthyophthirius (Ich) theronts and determined the effect of cutaneous antibodies in the skin culture fluid from fish immune to Ich on theronts apoptosis. Apoptosis was detected in theronts and was clearly distinguished by fluorescent microscopy after staining with acridine orange and propidium iodide. The apoptotic theronts showed characteristic chromatin condensation and nucleus fragments containing chromatin pieces. The externalization of phosphatidylserine (PS) on the plasma membrane of apoptotic theronts was detected with FITC conjugated annexin using flow cytometry. Theront apoptosis was induced using the skin culture fluid from fish immune to Ich, which contained cutaneous antibodies against Ich. The highest apoptosis appeared in theronts exposed to immune skin culture fluid at a 1:10 dilution compared to those at 1:20 and 1:40 dilutions. A direct correlation was noted between the percentage of apoptotic theronts and exposure duration to immune skin culture fluid. The result of this study showed that cutaneous antibodies in immune skin culture fluid played an important role in theront apoptosis.