Heavy metal toxicity has an immunomodulatory effect on metallothionein and glutathione peroxidase gene expression in Cyprinus carpio inhabiting a wetland lake and a culture pond.

The study provides cumulative data on the status of the two water bodies. The study designed revealed physicochemical properties (temperature, dissolved oxygen, pH, total dissolved solids and conductivity) to be in the desirable range, however, amongst the heavy metals excepting for Cd all were found to be higher than the permissible limits set by WHO and USEPA. It was observed that these elements cast their impact on bioindices (hepatosomatic index, condition factor, spleenosomatic index and kidney somatic index), renal marker enzyme (creatine kinase), hepatic marker enzymes (aspartate aminotransferase, alanine aminotransferase and alkaline phosphatase), histology of immune organs (liver, spleen, head-kidney and thymus) and level of serum immunoglobulin (IgM). Further, expression levels of Metallothionein (MT) and Glutathione peroxidase (GPX) genes in immune-related tissues (liver, spleen, head-kidney, thymus and blood) observed indicates metal pollution and abiotic stresses. These alterations are reliable indicators of the cellular and humoral immune response in Cyprinus carpio.