Latrotoxins and venom proteins (Latrodectus hasselti) (LTX)

Latrotoxins and associated venom proteins from the Redback spider (Latrodectus hasselti) represent a complex mixture of bioactive molecules, with alpha-latrotoxin being the most clinically significant component (Südhof, 2001). These toxins primarily target the presynaptic nerve terminals of vertebrates, where they bind to high-affinity receptors such as latrophilin-1, neurexin 1-alpha, and contactin (Ushkaryov et al., 2008). Upon binding, alpha-latrotoxin induces the formation of cation-permeable pores and triggers a massive, often calcium-independent, release of neurotransmitters like acetylcholine, GABA, and glutamate (Graudins et al., 2001). This neurotoxic action results in latrodectism, a condition characterized by severe local and systemic pain, hypertension, and diaphoresis (Isbister & Gray, 2003). While these proteins are not therapeutic targets for disease modification, they are the specific targets for neutralization by Redback spider antivenom (RBSAV), which consists of IgG antibodies designed to sequester the toxins and prevent their interaction with neuronal membranes (Isbister, 2010). The venom also contains smaller proteins and latroinsectotoxins that specifically target invertebrates, though these are of less clinical importance in humans (Garb & Hayashi, 2005). Research into these toxins has provided significant insights into the mechanisms of synaptic vesicle docking and fusion (Südhof, 2001). Therapeutic challenges include the rapid onset of symptoms and the potential for hypersensitivity reactions to equine-derived antivenoms (Isbister, 2010).

Other names

Redback spider venom proteinsAlpha-latrotoxinLatroinsectotoxinsLatrocrustatoxinsLow molecular weight proteinsLMWPs

Neutralization of venom components through antibody-mediated binding and sequestration, preventing toxin-receptor interaction at the presynaptic membrane.