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Leishmania amazonensis promastigotes evade complement killing by interfering with the late steps of the cascade

Authors :
Álvaro Cantini Nunes
Maria Fátima Horta
F. R. Almeida-Campos
F. J. Ramalho-Pinto
Source :
Parasitology. 115:601-609
Publication Year :
1997
Publisher :
Cambridge University Press (CUP), 1997.

Abstract

During their growth in vitro, promastigotes of Leishmania amazonensis undergo differentiation from complement-susceptible to complement-resistant forms. Here, we demonstrate that both forms bind comparable amounts of C3 on their surfaces, with the predominant molecule species being the haemolytically active C3b. Likewise, equivalent amounts of C9 are deposited on both forms of promastigotes. However, while C9-bearing complexes are exposed on the cell surface of resistant promastigotes, they are cryptic in the susceptible stage of the parasites. The membrane fraction of complement-resistant promastigote lysates has the ability to inhibit complement-mediated haemolysis, blocking C9, but not C3 deposition to complement-activating complexes. Moreover, the membrane fraction of complement-resistant promastigote lysates can inhibit the late steps of guinea-pig erythrocyte lysis much more efficiently than complement-susceptible ones. Our results indicate that L. amazonensis promastigotes evade complement killing by inhibiting the cytolytic pathway of the complement cascade.

Details

ISSN :
14698161 and 00311820
Volume :
115
Database :
OpenAIRE
Journal :
Parasitology
Accession number :
edsair.doi.dedup.....0451e0920f7216329716aba636f92fea