Isolation of an anticomplement factor from the venom of the Mojave rattlesnake (Crotalus scutulatus scutulatus).

Abstract

The venom of the Mojave rattlesnake was fractionated by DEAE-Sephadex column chromatography. A venom fraction, F5, inactivated both human and guinea pig complement. Both serum and purified C3 were partially converted to a protein of faster electrophoretic mobility, indicating that F5 had a direct proteolytic effect on C3. This product was capable of passively lysing guinea pig red blood cells. F5 very effectively inactivated the classical pathway, but only partially inactivated the alternative pathway. The venom fraction worked in a dose-dependent fashion, was heat labile but not lethal to mice at concentrations as high as 10 micrograms/g mouse weight. Antibodies were produced by immunizing rabbits with F5. The antibodies formed one precipitin line in gels against F5 and also neutralized the complement inactivating activity. The antibodies recognized the venom of the western diamondback rattlesnake, Crotalus atrox, but did not, however, recognize the crude venom of the Mojave rattlesnake.