Poster 12.  Congresso da Sociedade Brasileira de Toxinologia, 8., Symposium of the Pan American Section of the International Society on Toxinology, 8., 2004, Angra dos Reis, Brasil.  Abstracts...  J. Venom. Anim. Toxins incl.Trop. Dis., 2004, 10, 3, p.371.

 

 

Rabbit Antiserum Against Non-Toxic Subunit of Crotoxin Partially Neutralize its Neurotoxicity

 

Beghini, D.G.1, Rodrigues-Simioni, L.2, Novello, J.C.1, Hyslop, S.2, Marangoni, S.1

 

1 Depto. de Bioquímica, IB, UNICAMP and 2 Depto. de Farmacologia, FCM, UNICAMP, Campinas, SP.

 

Crotoxin is the main toxic component of the venom of Crotalusdurissus terrificus and Crotalusdurissus cascavella. Crotoxin is formed by the non-covalent association of two subunits: an acidic, non-enzymatic and non-toxic subunit, crotapotin, and a basic, weakly toxic PLA2 subunit. In present study was investigated the neutralization of neurotoxicity by rabbit antiserum against crotapotin obtained from crotoxin isolated from C. d. cascavella venom.

Rabbits were immunized with crotapotin, and antibody titer during immunization was monitored by ELISA. Anti-crotapotin serum had end-point dilutions determined by ELISA of 1.10-5. Immunoblotting showed a specific antiserum, which recognized crotapotin. The ability of the antiserum to neutralize the neurotoxicity of crotoxin and total venom from C. d. cascavella was assessed in mouse phrenic nerve-diaphragm preparations. Anti-crotapotin partially neutralized the neuromuscular blockade produced by venom and crotoxin at venom or toxin:antiserum ratios 1:10 (n=5) and 1:20 (n=5), respectively.

Binding studies have shown that crotapotin is temporarily involved in the binding of crotoxin with its target site, and is then released while PLA2 remains bound to the membranes. This explains how an anti-crotapotin can neutralize crotoxin by blocking the crotoxin interaction with its acceptor.

 

Financial support: FAPESP

 

Correspondence to: beghini@unicamp.br