Please use this identifier to cite or link to this item: https://www.arca.fiocruz.br/handle/icict/36336
Title: Cellular immune response in Rhodnius prolixus: Role of ecdysone in hemocyte phagocytosis
Authors: Figueiredo, Marcela B.
Castro, Daniele P.
Nogueira, Nadir F. S.
Garcia, Eloi S.
Azambuja, Patrícia
Affilliation: Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Rio de Janeiro, RJ, Brasil.
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Rio de Janeiro, RJ, Brasil.
Universidade Estadual do Norte Fluminense Darcy Ribeiro. Centro de Biociências e Biotecnologia. Laboratório de Biologia Celular e Tecidual. Campos dos Goytacazes, RJ, Brasil.
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Rio de Janeiro, RJ, Brasil.
Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Departamento de Bioquímica e Biologia Molecular. Rio de Janeiro, RJ, Brasil.
Abstract: In this paper we investigate in vivo and in vitro effects of orally administered azadirachtin and ecdysone on the phagocytic responses of Rhodnius prolixus 5th-instar larval hemocytes to the yeast Saccharomyces cerevisiae. Groups of insects fed non-treated blood (control) and insects that received azadirachtin plus ecdysone in the blood meal were inoculated with yeast cells in the hemocele. The injected yeast cells disappeared rapidly from the hemolymph, being removed completely by 90 min after inoculation. In the insects treated only with azadirachtin the clearance of free yeast circulating particles was significantly delayed compared to the two previously mentioned groups. It was demonstrated that the binding of yeast cells to hemocytes was reduced in the insects treated only with azadirachtin in comparison to both non-treated control and azadirachtin plus ecdysone-treated groups. Phagocytosis occurred when yeast cells were added to hemocyte monolayers prepared with hemolymph from blood fed insects, treated or not with azadirachtin plus ecdysone, so that yeast cells were rapidly bound to hemocytes and internalized in high numbers. By contrast, insects treated with azadirachtin exhibited a drastic reduction in the quantity of yeast cell–hemocyte binding and subsequent internalization. In all groups, the hemocytes attached to the glass slides were predominantly plasmatocytes. The magnitude and speed of the cellular response suggests that hemocyte phagocytosis is one of the main driving forces for the clearance of free circulating yeast cells from the hemolymph. We propose that ecdysone modulates phagocytosis in R. prolixus larvae, and that this effect is antagonized by azadirachtin.
Keywords: Phagocytosis
Ecdysone
Azadirachtin
Yeast
Rhodnius prolixus
Hemocytes
keywords: Fagocitose
Rhodnius prolixus
Fermento
Hemócitos
Ecdisona
Issue Date: 2006
Publisher: Elsevier
Citation: FIGUEIREDO, Marcela B. et al. Cellular immune response in Rhodnius prolixus: Role of ecdysone in hemocyte phagocytosis. Journal of Insect Physiology, v. 52, p. 711–716, 2006.
DOI: 10.1016/j.jinsphys.2006.03.011
ISSN: 0022-1910
Copyright: open access
Appears in Collections:IOC - Artigos de Periódicos

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