Mast cell activation by hornet (Vespa orientalis) venom

As far as its effect on the activation of rat peritoneal mast cells is concerned, the venom of young hornets (age 0-24 h) differs from that of adult hornets (over 24 h of age). 'Juvenile' venom caused activation mainly in rats previously sensitized to it, whereas 'adult' venom induced activation regardless of presensitization. Furthermore high concentrations of 'adult' venom were cytotoxic to the entire murine peritoneal cell population, but 'juvenile' venom was not toxic. SDS-PAGE data demonstrate that the venom of young hornets contains a unique component (82 kD), nonexistent in adult venom. Our data demonstrate that hornet venom activity is correlated with the hornet's age.