title: The suppressive effect of dexamethasone on the proliferation of Plasmodium falciparum in squirrel monkeys.
abstract: We investigated the effects of dexamethasone (Dx) on the proliferation of Plasmodium falciparum Indochina-I/CDC in squirrel monkeys (Saimiri sciureus boliviensis). Three splenectomized squirrel monkeys each received 16 perioral Dx doses (three times per week for 36 days), at three different dosages (0.2, 0.5, and 2.0 mg/ kg). Each monkey was intravenously inoculated with 7.8 x 10(7) red blood cells infected with P. falciparum 1 week after the initiation of Dx treatment. Parasite growth was suppressed in DX-treated monkeys in a dose-dependent manner. To determine whether this suppression of parasite development was mediated by host immunity, P. falciparum was cultured in vitro in the presence of Dx. The development of P. falciparum was also markedly suppressed in vitro by Dx treatment in a dose-dependent manner. These results suggest that Dx has a direct suppressive effect on the proliferation of P. falciparum both in vivo and in vitro, via a mechanism that is not mediated by an immunological reaction of the host.
authors.affiliation: Department of Molecular Immunology, School of Agriculture and Life Sciences, University of Tokyo, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Katakai
authors.forename: Syuzo
authors.initials: S
authors.lastname: Suzuki
authors.forename: Yoshikuni
authors.initials: Y
authors.lastname: Tanioka
authors.forename: Syosaku
authors.initials: S
authors.lastname: Hattori
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Masamichi
authors.initials: M
authors.lastname: Aikawa
authors.forename: Mamoru
authors.initials: M
authors.lastname: Ito
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D000962:Antimalarials / Q000494:pharmacology*; D018414:CD8-Positive T-Lymphocytes / Q000378:metabolism; D002478:Cells, Cultured; D003907:Dexamethasone / Q000494:pharmacology*; D004912:Erythrocytes / Q000469:parasitology; D005260:Female; D016778:Malaria, Falciparum / Q000276:immunology / Q000469:parasitology; D008297:Male; D010963:Plasmodium falciparum / Q000187:drug effects* / Q000254:growth & development; D012453:Saimiri
chemical_list: D000893:Anti-Inflammatory Agents; D000962:Antimalarials; D003907:Dexamethasone