Response of Sabella spallanzanii to multiple stressors. The combined effect of infection and copper sulphate.

The aim of this work is to study the immune responses of the polychaete Sabella spallanzanii after exposure to copper sulphate, an immunomodulating agent in marine organisms, and the multiple stresses caused by Escherichia coli infection, to validate the species as a model organism in marine-coastal biomonitoring programmes. Polychaetes were housed in laboratory and divided into five experimental groups: 1. Control (no microinjected), 2. filtered seawater + TBS injection (control of point 3), 3. filtered seawater + E. coli injection (control of point 4), 4. CuSO + TBS injection (control of point 5), and 5. CuSO + E. coli injection. The immune variables, esterase and alkaline phosphatase activity, cytotoxicity and detoxifying/antioxidant enzymes such as glutathione peroxidase were evaluated in total body extracts of the animals. Moreover, toll-like receptor, allograft inflammatory factor-1, lysozyme and haemagglutinating activity were investigated to highlight possible interactions. Indeed, the results of this work demonstrate the immunomodulating effect of copper sulphate on S. spallanzanii total body extracts related to oxidative stress and inflammatory markers.