Submitted to: Aquaculture America Conference
Publication Type: Proceedings
Publication Acceptance Date: 10/30/2001
Publication Date: 1/27/2002
Citation: Xu, D., Klesius, P.H. 2002. Antibody mediated immune response against ichthyophythirius using excised skin from channel catfish immune to ichthyophthirius. Aquaculture America Conference. Interpretive Summary:
Technical Abstract: Fish that survived the infection of ciliated protozoan Ichthyophthirius multifiliis(Ich) developed an immune response and become resistant to the parasite reinfection. This study investigated antibody mediated immune response against Ich by determining whether theronts could retain the potential for re-infection, both in vitro and in vivo, after treatment with hthe culture fluid of excised skin from channel catfish immune to Ich. Skin of the channel catfish immune to Ich was collected for culture and the culture fluid was harvested at 24h of incubation and used to treat theronts Theronts were immobilized and agglutinated by the culture fluid from immune fish at the dilution 1:64 or lower. The invasion was reduced significantly for theronts treated with the immune culture fluid compared to theronts treated with the culture fluid of the excised skin from non- infected fish. The treatment of theronts with the immune culture fluid greatly reduced the size of trophonts compared to the trophont size developed from control theronts. Trophonts developed from theronts treated with the immune culture fluid showed lower survival after 24h PE compared to those from control theronts. The infection was severe for fish invaded by theronts treated with the culture fluid from naive fish; the number of infected fish and the density of trophont per fish were high. In summary, results of this study show that cutaneous antibody in the culture fluid of excised skin from immune fish significantly reduce theront infectivity by immobilizing or killing theronts.