Expression analysis and tissue localization of IgZ in the grouper <i>Epinephelus coioides</i> after <i>Vibrio alginolyticus</i> infection and vaccination

The orange-spotted grouper (Epinephelus coioides) is an important marine farmed fish in China. It affected by the bacterial pathogen Vibrio alginolyticus, which causes high mortality and substantial economic losses. We studied transcriptional changes of IgZ gene E. coioides following V. alginolyticus stimulation investigated distribution different tissues. highest expression level occurred head kidney. When were stimulated with live inactivated levels kidney, spleen, intestine, gills blood cells significantly upregulated. In situ hybridization study, mRNA-positive detected spleen gill, but positive signals not liver intestine. IgZ-labelled increased post-infection for 21 days. present study provides additional evidence that involved mucosal immune responses helps explain role defence against infection.