Immunogenetic and protective activity of an extract of Schistosoma mansoni

Abstract

The immunogenic and protective activity of an extract of S. mansoni, obtained by incubation of viable adult worms in buffered saline, was evaluated in rabbits and mice. Animal immunization with this extract resulted in the development of both humoral and cellular immune response. All immunized rabbits developed high levels (91 to 100%) of cytotoxic antibodies as determined by in vitro assays of cytotoxic activity of their sera against viable schistosomules. Immunized animals challenged with S. mansoni cercariae showed a lower parasite load than that of normal controls. Protective activity was 88.6% and 54.0% in immunized rabbits and mice, respectively.<br>Avaliou-se em coelhos e camundongos, a atividade imunogênica e protetora de um extrato antigênico de Schistosoma mansoni, obtido pela estocagem de vermes adultos em solução salina tamponada (Extrato Salino). A imunização dos animais determinou o desenvolvimento de resposta imune celular e humoral, avaliada por provas específicas. Todos os coelhos imunizados com ES, desenvolveram altos níveis de anticorpo citotóxico (91 a 100%), determinados pela avaliação da atividade citotóxica in vitro, contra esquitossômulos. Concluiu-se que os coelhos e camundongos imunizados com o extrato salino apresentaram diminuição da carga parasitária oriunda da infecção posterior com cercárias do S. mansoni, em relação aos controles. Os percentuais de proteção foram de 88.6% e 54% para os animais vacinados (coelhos e camundongos respectivamente)

Current Status of the Sm14/GLA-SE Schistosomiasis Vaccine: Overcoming Barriers and Paradigms towards the First Anti-Parasitic Human(itarian) Vaccine

“…Rather than lyophilized parasites, generally used by other research groups, a saline extract containing secreted/excreted antigens derived from living adult schistosomes was utilized for initial immunizations. The restricted number of potential protective antigens released in this saline extract allowed an accelerated identification of strong antigen candidates for molecular analysis and gene cloning [18,19,20,21,22]. Innovative methods were also adopted for the assessment of immunity, where the use of outbred models, in contrast to the commonly-employed inbred animals, allowed a better representation of the ultimate target population and provided a unique opportunity to develop an alternative strategy for the assessment of protective immunity.…”

Preliminary analysis of Sm14 in distinct fractions of Schistosoma mansoni adult worm extract

“…Living worms were then allowed to stand at room temperature (28ºC to 30ºC) in fresh PBS (phosphate buffered saline) for 2-3 h, and frozen at -20ºC. After thawing, PBS suspensions of the worms (1g worms/10 ml PBS) were filtered through a wire mesh, and centrifuged at 10,000 g for 1 h at 4ºC (Tendler & Scapin 1981, Tendler et al 1982. The protein content of SE was assessed by Lowry's method (Lowry et al 1951), and stock batches containing 1 mg/ml were stored at -20ºC.…”

A High Potent Antibody Response in Rabbits Infected With Ultra Violet Attenuated Cercariae

“…Antigenic preparations from Schistosoma mansoni adult worms have been tested for their efficacy in stimulating resistance to subsequent infection of experimental animals. Immunization of mice with adult worm extract resulted in 54% reduction of the parasite load while adult worm-immunized rabbits displayed 88% reduction and developed higher levels (91-100%) of cytotoxic antibodies (Tendler et al, 1982).…”