Antidote to snakebite hidden in the immune system

New research suggests that immune cells called mast cells help protect mice from certain snakebites and @#@255@#@ stings. Although mast cells are best known for their role in helping produce the symptoms of anaphylactic shock, asthma and allergies, scientists also recognize other supporting roles these cells play in the immune system's fight against infection. The venom of many insects and reptiles contains chemicals that can activate mast cells, so researchers generally believed that mast cells' role was to worsen the harm of snakebites or insect stings. However, a new study by Martin Metz and colleagues shows that snake and bee venom is more harmful to mice lacking mast cells than to normal mice. Experiments using the venom of the Israeli mole viper suggest that mast cells provide protection by releasing carboxypeptidase A, an enzyme that degrades a dangerous component of the venom, suggesting possible new directions for antidote research. Snakebites contain varying amounts of venom, and mast cells have the greatest effect on venom at below or near lethal doses, said Stephen Galli, the paper's corresponding author.