Assessing Fish Immunotoxicity by Means of In Vitro Assays: Are We There Yet?

Abstract

There is growing awareness that a range of environmental chemicals target the immune system of fish and may compromise the resistance towards infectious pathogens. Existing concepts to assess chemical hazards to fish, however, do not consider immunotoxicity. Over recent years, the application of in vitro assays for ecotoxicological hazard assessment has gained momentum, what leads to the question whether in vitro assays using piscine immune cells might be suitable to evaluate immunotoxic potentials of environmental chemicals to fish. In vitro systems using primary immune cells or immune cells lines have been established from a wide array of fish species and basically from all immune tissues, and in principal these assays should be able to detect chemical impacts on diverse immune functions. In fact, in vitro assays were found to be a valuable tool in investigating the mechanisms and modes of action through which environmental agents interfere with immune cell functions. However, at the current state of knowledge the usefulness of these assays for immunotoxicity screening in the context of chemical hazard assessment appears questionable. This is mainly due to a lack of assay standardization, and an insufficient knowledge of assay performance with respect to false positive or false negative signals for the different toxicant groups and different immune functions. Also the predictivity of the in vitro immunotoxicity assays for the in vivo immunotoxic response of fishes is uncertain. In conclusion, the currently available database is too limited to support the routine application of piscine in vitro assays as screening tool for assessing immunotoxic potentials of environmental chemicals to fish.

Insights into Toxic Prymnesium parvum Blooms as a Cause of the Ecological Disaster on the Odra River

“…Toxins can pose a lethal threat to aquatic fish for several reasons They can, for example, (1) damage gills and other organs, making it difficult for fish to breathe and survive; (2) disrupt the nervous system, leading to disorientation, paralysis, and death [ 23 ]; (3) damage the liver, kidneys, and other organs, leading to organ failure and death [ 24 ]; (4) disrupt the hormonal system, leading to reproductive failure [ 25 , 26 , 27 ]; (5) disrupt the immune system and make fish more susceptible to disease [ 28 , 29 ]; (6) impair fish growth and development, leading to abnormal growth or even death [ 30 ]; and (7) accumulate in fish tissues and can be passed through the food chain, making fish unsafe for human consumption [ 31 ]. It is important to know that toxic substances can come from many sources, including industrial pollution, agricultural runoff [ 32 , 33 ], and even naturally occurring toxins produced by certain species of algae or bacteria [ 34 , 35 ].…”

Skin mucosal immune-parameters and expression of the immune-relevant genes in Danio rerio treated by white button mushroom (Agaricus bisporus)

“…As a result, it leads to an increase in the use of antibiotics that should often be administrated for a short time, orally or by adding medications to a tank or cage (Defoirdt et al, 2011;Shiry et al, 2019a). Drug interactions with lymphoid tissues may alter the function or structure of the immune system (Segner et al, 2022). It causes adverse effects such as immunosuppression, uncontrolled cell proliferation, altered host defense mechanisms against pathogens, and even neoplasia (Tu et al, 2010;Yonar et al, 2011).…”