Amphibian populations have decreased by ~40% over the past three decades, capturing the interest of both the scientific community and the general public. A leading hypothesis to explain these declines is that pollutants weaken amphibian immune function such that subsequent exposure to pathogens results in increased disease susceptibility and death. Therefore, measures of immune function provide a way to analyze how pollutant exposure may be linked to disease susceptibility. Furthermore, amphibians can serve as model organisms for immunotoxicity because they share many of the same structural and functional immunological features as mammals and fishes, making it possible to transfer knowledge to other vertebrates. Per- and polyfluorinated substances (PFAS), a.k.a., “forever chemicals”, have emerged as chemicals of concern as more and more PFAS-contaminated sites are identified in Wisconsin ecosystems, and little is known about their immunotoxic effects. We will expose newly hatched Xenopus laevis tadpoles to environmentally relevant levels of PFAS and employ functional immune assays, like respiratory burst and hemolysis to investigate potential immunotoxicity. Students conducting this research will gain experience in animal husbandry, experimental design, trouble-shooting, data analysis, and laboratory techniques.