Small Marine Neurotoxin Elicits Common Antibody Response in Zebrafish and Sea Lions

The neurotoxic amino acid, domoic acid, is naturally produced by marine phytoplankton and presents a significant health threat to marine mammal and human populations. Currently, diagnostic tools to assess exposure are not available, yet concerns regarding health impacts associated with low-level repetitive exposure are growing. Here we applied a laboratory zebrafish model to assess exposure to asymptomatic doses of domoic acid in a nine-month low-level repetitive exposure study. Blood analyses, whole brain gene expression, and functional lymphocyte proliferation assays analyzed at 11 time points revealed a quantifiable antibody response that was temporally correlated with upregulated immune response genes and significantly increased spontaneous lymphocyte proliferation. The antibody response was further validated in field exposed California sea lions and provides the first biomarker for chronic exposure assessment. Time series domoic acid exposure of zebrafish.