To address the neutralization of lNTx and sNTx, we measured nAChR currents in a human rhabdomyosarcoma cell line in patch clamp assays36 and observed that pre-incubation of anti-lNTx (a-lNTx) VHHs with lNTx-3, lNTx-5 and lNTx-7 or anti-sNTx VHHs with sNTx-1, sNTx-3 and sNTx-6 before addition to the cells protected the nAChR-mediated current—that is, they showed complete inhibition of neurotoxicity down to a 1:1 molar ratio between VHH and toxin (Fig. 3a). Here, CHRNA4 is linked to rhabdomyosarcoma.