Influence of human chorionic gonadotropin (hCG) on in vitro growth of Plasmodium falciparum

Abstract

<p>Abstract</p> <p>Background</p> <p>During pregnancy, women are more susceptible to <it>Plasmodium falciparum </it>infections and frequently have a higher parasitaemia than non-pregnant women. Several mechanisms are responsible for their increased susceptibility, including down-modulation of immune responses that aid in parasite clearance and sequestration of infected erythrocytes in the placenta. Early in pregnancy, a third mechanism may contribute to higher parasitaemia, since it has been reported that addition of human chorionic gonadotropin (hCG) to <it>in vitro </it>cultures of the NF54-strain of <it>P. falciparum </it>results in increased parasite growth rates. The goal of this study was to further examine the effect of hCG on <it>P. falciparum </it>growth.</p> <p>Methods</p> <p>The NF54-3D7, FVO and 7G8 strains of <it>P. falciparum </it>were cultured <it>in vitro </it>with various physiological concentrations of hCG purchased from three sources. Infected erythrocytes were also co-cultured with a human cell line that naturally secretes hCG.</p> <p>Results</p> <p>Results from 14 experiments using different combinations of parasite strains and concentrations of hCG from different sources, as well as the co-culture studies, failed to provide convincing evidence that hCG enhances parasite growth <it>in vitro</it>.</p> <p>Conclusion</p> <p>Based on these data, it seems unlikely that hCG has a direct effect on the rate of parasite growth early in pregnancy.</p