Aroclor 1254 inhibits the chemiluminescence response of peritoneal cavity cells from sharpsnout sea bream (Diplodus puntazzo)

• Aroclor 1254, PCB mixtures, affects the Diplodus puntazzo innate immunity.
• PCB increases the in vivo and in vitro chemiluminescence response of cells.
• The chemiluminescence response modulation can be imputed to a phagocyte activation.

Chronic exposure to polychlorinated biphenyls (PCBs) affect the immune system of fish and could lead to a decreased disease resistance. The effects of Aroclor 1254, PCB mixtures, on the Diplodus puntazzo innate immunity were examined by assaying the zymosan stimulated chemiluminescence response (CL) of peritoneal cavity cells (PCCs) at various times (1, 24, 48 h and 1–4 weeks) from intraperitoneal injection of the xenobiotic (1 mg kg−1 body weight). Controls were performed by assaying cells from medium-treated fish. Since the kinetic of the chemiluminescence response showed the highest peak at 25 min after the zymosan stimulation of the cells, the values found at that time were considered. The CL enhancement observed at 1 h after the treatment with xenobiotic was followed by a decreased response at 24 h and appeared to be lower at 1–4 weeks when compared to the CL response of the control, suggesting a protracted effect of PCBs on the peritoneal cavity. Since PCCs incubated in vitro for 1 h with 0.05 and 0.1 μg ml−1 Aroclor showed an enhanced CL, the effect of the xenobiotic could be exerted on the cell responsiveness to zymosan. It is known that fish CL response of PCCs can be imputed to phagocyte (macrophages and neutrophils) activation, these cells and their responsiveness to zymosan can be used in immunotoxicology assay to monitor the fish health in polluted environment.