Mapping of B cell epitopes in an immunodominant antigen of Trypanosoma cruzi using fusions to the Escherichia coli LamB protein

The JL8 protein antigen from Trypanosoma cii , a dominant immunogen in man, has been characterized as containing tandem amino acid repeats. Here, we describe the use of the LamB protein of Escherichia coli as a carl icr of JL8 derived sequences in order to map the immunodominant B cell epitopes in this antigen. Five different sequences of JL8 were inserted in the LamB protein and the JL8-LamB fusion proteins were tested by ELISA with human chronic chagasic sera. the fusion carrying the sequence AEKQKAAEATKVAE was recognized by most sera. This protein was also capable of inhibiting the binding of human chagasic antibodies to GST-JL8 in competitive ELISA suggesting that it contains an immunodominant B cell epitope of JL8. (C) 1998 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.Universidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, BR-04023062 São Paulo, BrazilIngebi, RA-1428 Buenos Aires, DF, ArgentinaUniversidade Federal de São Paulo, Escola Paulista Med, Dept Microbiol Imunol & Parasitol, BR-04023062 São Paulo, BrazilWeb of Scienc

Trypanocidal activity of eErythrina speciosa Andr. (Leguminosae)

Investigation of the bioactive crude extracts from the leaves of Erythrina speciosa Andr. (Leguminosae-Papilionoideae) from Brazil led to the isolation of nororientaline as a new alkaloid in this plant. The activity of crude extract and alkaloids, isolated from leaves of E. speciosa were evaluated against Trypanosoma cruzi epimastigotes and trypomastigotes in vitro. Our results show that crude alcoholic extract of E. speciosa (Et-Es) and alkaloids containing nororientaline at 250 μg/mL, 500 μg/mL and 1000 μg/mL inhibited 50, 60 and 80 % of epimastigote growth, respectively (p < 0.001). Et-Es showed activity against trypomastigote forms in 80 % and 60 % at 1000 μg/mL and 500 μg/mL, respectively. When tested against macrophages, the same extract did not affect the cell viability as measured by luminescent assay, suggesting that it should be considered as a leading structure for further research.Colegio de Farmacéuticos de la Provincia de Buenos Aire