Submitted to: International Aquaculture Meeting
Publication Type: Proceedings
Publication Acceptance Date: July 12, 2006
Publication Date: September 2, 2006
Citation: Xu, D., Klesius, P.H., Shoemaker, C.A. 2006. FAS expression and apoptosis in the fish parasite Ichthyophthirus. 5th International Symposium on Aquatic Animal Health. San Francisco, CA. September 2 - 6, 2006. P. 280. Technical Abstract: Fish that survive an infection by Ichthyophthirius multifiliis (Ich) develop antibodies that immobilize and kill Ich theronts. Apoptosis of I. multifiliis theronts was caused by cutaneous antibody from channel catfish immune to Ich. The mechanism for cutaneous antibody to induce apoptosis of theronts is unclear. In the present study, we investigated the expression of type I-membrane Fas receptors on the surface of Ich theronts and the possible association between Fas expression and theront apoptosis caused by cutaneous antibody. Fas receptors were detected on the theronts surface using fluorescein isothiocyanate-conjugated mouse monoclonal-antibody against the Fas. Fas-positive theronts significantly increased with in vitro time incubation and theront concentration. Fas ligand did not caused theront apoptosis. A highly significant correlation was noted between theront Fas expression and theront apoptosis induced by immune cutaneous antibody (correlation coefficient = 0.95, P < 0.01). Numbers of apoptotic theronts increased with the increment in the number of Fas positive theronts. The data indicated that theront apoptosis induced by immune cutaneous antibody appears to be positively correlated with the expression of Fas on the surface of Ich theronts.