Antibodies to sea anemone nematocyst venom-II. Neutralization of the hemolytic, phospholipase A₂ and lethal activities by purified antibodies produced in response to attenuated venom

D. A. Hessinger and R. I. Grove. Antibodies to sea anemone nematocyst venom-II. Neutralization of the hemolytic, phospholipase A₂ and lethal activities by purified antibodies produced in response to attenuated venom. Toxicon 17, 109-120, 1979.-The IgG class of antibodies was purified from rabbit serum following the primary immune response to attenuated nematocyst venom from the sea anemone, Aiptasia pallida. This immune IgG fraction was judged to be pure immunoglobulin class G by serological and electrophoretic criteria. The amounts of immune IgG which specifically inhibited the hemolytic, phospholipase A₂ and lethal activities of the venom were determined and related to the possible mechanisms of hemolysis and mouse lethality. The i.v. mouse ld₅₀ of active anemone venom was 136 μg/kg, making it the most toxic of the reported cnidarian venoms. The implications of the rapid onset of toxic symptoms and the very steep dose-response curve are discussed in terms of the possible mechanism of lethality.