Plasmodium chabaudi: estradiol suppresses acquiring, but not once-acquired immunity.
This study investigates the effect of estradiol (E) on self-healing of Plasmodium chabaudi malaria in mice of the inbred strain C57BL/10. Our data show: (1) Female mice and male castrates are capable of self-healing infections when challenged with 10(6) P. chabaudi-infected erythrocytes. Self-healing is completely suppressed after pretreatment of mice with 12 micrograms E injected sc twice a week for 3 weeks. (2) The suppressive effect of E is prevented by the estrogen receptor blockers tamoxifen and clomiphene. (3) The nonsteroidal E-agonist diethylstilbestrol (DES) also suppresses self-healing. This suppressive DES effect is prevented by tamoxifen. (4) In mice immune to P. chabaudi, neither survival rate nor the course of parasitemia is affected by E, even at 10-fold higher E doses. Our data suggest that the immunosuppressive action of E is a specific genomic effect, i.e., E-induced gene products prevent the development of protective immunity against P. chabaudi.
Benten
W P
WP
Division of Parasitology, Heinrich-Heine-University, Freiburg, Germany.
Wunderlich
F
F
Mossmann
H
H
D000818:Animals; D002369:Castration; D002996:Clomiphene / Q000494:pharmacology; D004054:Diethylstilbestrol / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D007108:Immune Tolerance / Q000187:drug effects*; D007110:Immunity, Active / Q000187:drug effects; D008288:Malaria / Q000276:immunology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016788:Plasmodium chabaudi / Q000276:immunology*; D013629:Tamoxifen / Q000494:pharmacology
D013629:Tamoxifen; D002996:Clomiphene; D004958:Estradiol; D004054:Diethylstilbestrol