Mast Cells May Increase Resistance to Animal Venom
Mouse study suggests that mast cells produce proteases that help counter toxic effects
THURSDAY, July 27 (HealthDay News) -- Contrary to previous thought, the mast cell -- best known for producing symptoms of allergies, asthma and anaphylactic shock -- may actually help protect against the toxic effects of some animal venoms by releasing proteases, according to the results of a mouse study published in the July 28 issue of Science.
Stephen Galli, M.D., of the Stanford University School of Medicine in Stanford, Calif., and colleagues studied the effects of venom from three species of poisonous snakes and one species of honeybee on wild-type mice and mast cell-deficient mice.
The researchers found that the wild-type mice could withstand 10 times as much snake venom as the mast cell-deficient mice. At least part of the reason, they report, is because mast cells release the enzyme carboxypeptidase A and possibly other proteases that degrade snake venom. They also found that mast cells significantly reduced the toxicity and mortality associated with honeybee venom.
"We have identified a heretofore unproven role for mast cells: enhancing innate host resistance to the toxicity of certain animal venoms," the authors conclude. "Our observations also provide a new perspective on the presence, within mast cells, of prominent cytoplasmic granules that contain a large amount and, in some species, a large diversity, of proteases."