Hemozoin from Schistosoma japonicum does not affect murine myeloid dendritic cell function.

Hemozoin (Hz) formation is a byproduct of hemoglobin digestion in some hematophagous organisms. Although Hz produced by Plasmodium falciparum (PfHz) has been shown to affect development and activities of human dendritic cells (DCs), the effects of Schistosoma Hz on DCs have not been elucidated. Our data presented in this report demonstrated that native Schistosoma japonica Hz (SjHz) did not affect the differentiation of murine bone marrow cells into immature DCs (imDCs). Maturation and stimulatory activities to T cells by imDCs induced by LPS were not altered in the presence of SjHz; whereas purified PfHz induced a slight increase in CD40 expression and enhanced IL-12p40 secretion. Lastly, SjHz treatment did not significantly affect the phagocytic activities of DCs. These data suggested that SjHz failed to exert any significant effects on the development and activities of murine myeloid DCs. The mechanisms of different effects on DCs by SjHz and PfHz remain to be elucidated.