Evaluation of the humoral response and serum neutralization capacity of Swiss mice inoculated with natural and Cobalt-60-irradiated Crotalus durissus terrificus, Bothrops jararaca, Bothrops jararacussu, and Bothrops moojeni venoms

THESIS.R. S. Ferreira Júnior submitted this dissertation for his Masters in Tropical Diseases at Botucatu School of Medicine, São Paulo State University, UNESP, Botucatu, São Paulo, Brazil, 2003.

Advisor: Professor Domingos Alves Meira

Co-advisor: Professor Benedito Barraviera

ABSTRACT. ELISA was used to evaluate, follow, and compare the humoral immune response of SWISS mice during hyperimmunization with natural and Cobalt-60-irradiated (⁶⁰Co) Crotalus durissus terrificus, Bothrops jararaca, Bothrops jararacussu, and Bothrops moojeni venoms. Potency and neutralization were evaluated by in vitro challenges. After hyperimmunization, immunity was observed by in vivo challenge and the side effects were assessed. The animals’ immunization with one LD50 of each venom was on days one, 15, 21, 30, and 45, when blood samples were collected; the challenges occurred on the 60^th day. Results showed that ELISA was efficient in evaluating, following, and comparing mouse immune response during hyperimmunization. Serum titers produced with natural venom were similar to those with irradiated venom. Immunogenic capacity was maintained after ⁶⁰Co irradiation. Serum produced from Crotalus durissus terrificus irradiated venom showed higher potency and neutralization capacity than that from natural venom. Antibodies from natural and irradiated venom by in vitro challenges were also efficient in neutralizing Bothrops jararaca, Bothrops jararacussu, and Bothrops moojeni venoms. All antibodies were capable of neutralizing five LD50 from these venoms. Clinical alterations were minimum during hyperimmunization with irradiated venom and evident with natural venom.

KEY WORDS: hyperimmunization; irradiation; snake venom; ELISA; serum neutralization.

CORRESPONDENCE TO: R. S. Ferreira Junior – Centro de Estudos de Venenos e Animais Peçonhentos (CEVAP), UNESP, Caixa Postal 577, 18618-000, Botucatu, São Paulo, Brasil. E-mail: rseabra@cevap.org.br