NEUTRALIZING ACTIVITY OF EXPERIMENTAL Thalassophryne nattereri FISH ANTIVENOM PRODUCED IN HORSE

Piran-Soares, A.A.(1), Takehara, H.Á.(1), Távora, J.P.F.(2), Guidolin, R.(3), Higashi, H.G.(3), Lopes-Ferreira, M.(1)

(1)Laboratório de Imunopatologia, (2)Fazenda São Joaquim, (3)Divisão de Desenvolvimento Tecnológico e Produção, Instituto Butantan, São Paulo, Brasil.

Poisoning due to Thalassophryne nattereri (niquim) venom constitutes a serious health problem for fishermen, particularly in the north and northeast of Brazil. The venom causes strong local effect such as intense pain, edema and necrosis. The present therapy with anti-inflammatory and analgesic drugs is ineffective. To evaluate horse serum therapy as an alternative treatment, animals were immunized with sc injections of crude venom. A strong antibody response was observed as measured by ELISA (titer of 8,192,000). Immunoblotting assay showed that the antivenom was effective to recognize all the proteins present in the venom. Regarding its specificity, the antivenom only reacted with venoms of Thalassophryne maculosa and the genus Potamotrygon (ray). Neutralization of edema, nociception, necrosis and lethality was evaluated after pre-incubating the antivenom with venom for 30 min, at 37^o C. Controls were similarly treated using normal horse serum. The total neutralization of the lethality induced by 5LD₅₀ venom (455 mg) was obtained with 400 mL antivenom. Necrosis (100 mg venom) and nociception (3 mg) were also completely neutralized with 200 and 30 mL antivenom, respectively. Edema was only partially neutralized even when large amounts of antivenom were used. These data suggest that horse antivenom therapy may be a promising approach for patients damaged by T. nattereri venom.

Supported by FAPESP (01/11032-3)

CORRESPONDENCE TO:

Ana Amélia Chagas Piran Soares, Avenida Engenheiro Heitor Antonio Eiras Garcia, 396, Apto. 63M, São Paulo, SP, CEP: 05588-000, Brasil, Email: nelson_ana@uol.com.br