Antibodies to a phospholipase A2 from Vipera russelli selectively neutralize venom neurotoxicity.

Polyclonal antibodies to a purified neurotoxic phospholipase A2 (PLA2), VRV PL-VIIIa, from Vipera russelli venom were raised in rabbits. Anti-PL-VIIIa-Ig (gamma-globulin fraction of rabbit antiserum injected with VRV PL-VIIIa) selectively neutralized the neurotoxicity of VRV PL-VIIIa, VRV PL-V, VRV PL-VI (neurotoxic PLA2 of V. russelli venom) and whole V. russelli venom without affecting their PLA2 activity, which clearly demonstrates that the catalytic site and the neurotoxic site (the site through which the PLA2 binds to the nervous system) are distinct on a PLA2 molecule. Anti-PL-VIIIa Ig did not have any effect on the oedema-inducing activity and indirect haemolytic activity of VRV PL-VIIIa, VRV PL-V and VRV PL-VI, which are attributed to the PLA2 activity of the peptide, but inhibited their anti-coagulant potency.