Mechanism of protection induced by vitamin A in falciparum malaria.
Supplementation with vitamin A potentiates host resistance to malaria, however, the underlying mechanism is unknown. We tested the effects of 9-cis-retinoic acid, a metabolite of vitamin A, on CD36 expression, non-opsonic phagocytic clearance of parasitised erythrocytes, and TNFalpha production in human monocytes and macrophages. We found reduced secretion of TNFalpha, upregulated CD36 expression, and increased phagocytosis of Plasmodium falciparum-parasitised erythrocytes. Increased parasite clearance and reduced proinflammatory cytokine responses to infection might partly explain the beneficial effects of supplementation with vitamin A in malaria.
Serghides
Lena
L
Tropical Disease Unit, Division of Infectious Diseases, Department of Medicine, Toronto General Hospital and the University of Ontario M5G 2C4, Toronto, Canada.
Kain
Kevin C
KC
D000077556:Alitretinoin; D000818:Animals; D000981:Antiprotozoal Agents / Q000008:administration & dosage / Q000494:pharmacology*; D018955:CD36 Antigens / Q000187:drug effects; D002648:Child; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism / Q000469:parasitology; D006801:Humans; D016778:Malaria, Falciparum / Q000097:blood* / Q000188:drug therapy*; D010587:Phagocytosis / Q000187:drug effects; D010963:Plasmodium falciparum / Q000187:drug effects*; D014212:Tretinoin / Q000008:administration & dosage / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D014801:Vitamin A / Q000008:administration & dosage / Q000494:pharmacology*
D000981:Antiprotozoal Agents; D018955:CD36 Antigens; D014409:Tumor Necrosis Factor-alpha; D014801:Vitamin A; D000077556:Alitretinoin; D014212:Tretinoin