Mechanistic insights into antibody recognition of tetrodotoxin analogues: Implications for neurotoxicological assessment

Tetrodotoxins (TTXs) pose significant food safety risks due to their potent neurotoxicity. Growing concerns about the impact of these toxins on public health have driven the development of new detection methods, with immunoassays showing strong potential. However, limited knowledge of the cross-reactivity of anti-TTX antibodies with analogues may compromise the reliability of these assays in food safety applications. To address this, cross-reactivity factors (CRFs) for five TTX analogues (i.e., 11-norTTX-6(S)-ol, 11-deoxyTTX, 6,11-dideoxyTTX, 5,11-dideoxyTTX, and 5,6,11-trideoxyTTX) were assessed using a magnetic bead-based immunoassay. In parallel, the antibody's ability to neutralise the toxicity of TTX analogues was evaluated in Neuro-2a cells using automated patch clamp, a single-cell biosensing platform specifically designed for in vitro toxicity assessment and characterisation. Antibody cross-reactivity towards the tested analogues correlated with their relative toxicity, enabling a selective detection of the most hazardous compounds. These findings highlight the dual role of molecular structure in dictating both toxicological potency and immunological recognition, and support the use of immunoassays as effective tools for TTX monitoring in food safety applications.