Schistosoma mansoni soluble egg antigens are internalized by human dendritic cells through multiple C-type lectins and suppress TLR-induced dendritic cell activation.
van Liempt, Ellis; van Vliet, Sandra J. 1; Engering, Anneke 1; Garcia Vallejo, Juan Jesus; Bank, Christine M.C.; Sanchez-Hernandez, Marta; van Kooyk, Yvette; van Die, Irma *
[Article] Molecular Immunology. 44(10):2605-2615, April 2007.

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: In schistosomiasis, a parasitic disease caused by helminths, the parasite eggs induce a T helper 2 cell (TH2) response in the host. Here, the specific role of human monocyte-derived dendritic cells (DCs) in initiation and polarization of the egg-specific T cell responses was examined. We demonstrate that immature DCs (iDCs) pulsed with schistosome soluble egg antigens (SEA) do not show an increase in expression of co-stimulatory molecules or cytokines, indicating that no conventional maturation was induced. The ability of SEA to affect the Toll-like receptor (TLR) induced maturation of iDCs was examined by copulsing the DCs with SEA and TLR-ligands. SEA suppressed both the maturation of iDCs induced by poly-I:C and LPS, as indicated by a decrease in co-stimulatory molecule expression and production of IL-12, IL-6 and TNF-[alpha]. In addition, SEA suppressed TH1 responses induced by the poly-I:C-pulsed DCs, and skewed the LPS-induced mixed response towards a TH2 response. Immature DCs rapidly internalized SEA through the C-type lectins DC-SIGN, MGL and the mannose receptor and the antigens were targeted to MHC class II-positive lysosomal compartments. The internalization of SEA by multiple C-type lectins may be important to regulate the response of the iDCs to TLR-induced signals.

(C) 2007Elsevier, Inc.