The suppressive effect of dexamethasone on the proliferation of Plasmodium falciparum in squirrel monkeys.
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.
Katakai
Yuko
Y
Department of Molecular Immunology, School of Agriculture and Life Sciences, University of Tokyo, Japan.
Suzuki
Syuzo
S
Tanioka
Yoshikuni
Y
Hattori
Syosaku
S
Matsumoto
Yoshitsugu
Y
Aikawa
Masamichi
M
Ito
Mamoru
M
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
D000893:Anti-Inflammatory Agents; D000962:Antimalarials; D003907:Dexamethasone