Improvement of Malayan cobra (Naja naja sputatrix) antivenin.

A low molecular weight toxic fraction was isolated from venom of the Malayan cobra (Naja naja sputatrix) by Sephadex G-50 gel filtration chromatography. The fraction accounted for almost 100% of the venom lethality. Antisera were prepared by immunizing rabbits with the low molecular weight toxic fraction, the glutaraldehyde-treated low molecular weight toxic fraction and the glutaraldehyde-treated, sea snake neurotoxin-enriched low molecular weight toxic fraction, respectively. Only the serum of rabbits immunized with the glutaraldehyde-treated, neurotoxin-enriched fraction gave effective protection against high doses of Malayan cobra venom. This antiserum is thus a potent Malayan cobra antivenin. One milliliter of this antiserum was able to neutralize 1.5 mg of Malayan cobra venom. It is thus 4-8 times more potent than the commercially available Malayan cobra antivenins produced by immunizing horses with whole Malayan cobra venom.