Previously we demonstrated that schistosome egg glycans are largely responsible for parasite induced immunomodulation and Th2-biasing. We identified LNFPIII and LNnT as two glycans present on schistosome eggs that drive immune modulation in vifro and in vivo. These glycans induce immune suppression and CD4+ Th2-type responses when presented 10 antigen presenting cells as glyco-conjugales. The overall goal of this renewal application is to understand how defined schistosome glycans activate APCs in such a manner that these APCs drive anti-inflammatory responses. Alternative activation of human DCs by soluble egg antigens occurs through three Ctype lectins: mannose receptor (MR), macrophage galactose receptor (MgI) and DC-SIGN. LNFPIlI binds to each of these lectins and to MSIGNR1 . Therefore we will perform experiments in mice deficient in these lectins or use HEK cells singly transfected with these lectins to examine their roles in LNFPIII induced APC activation. In addition, by transfecting HEK cells expressing TLR4/CD14/MD2 with these same C-type lectins we will determine if activation of APes via these lectins alters Toll-like receptor induced signaling. Because C-type lectin-ligand interaction leads to endosome formation, we will examine the role endosome formation plays in alternative activation using inhibitors of endosome formation. We have performed microarray analysis to examine signaling pathways downstream of LNFPlIl activation and Identify candidate genes. We will use RT -PCR to validate several candidate genes and then siRNA to knockdown these genes to determine if their role is critical for alternative activation. For proteins we will use Rules Based Medicine (RBM) analysis to measure levels of >72 proteins known to be involved in innate activation of APCs.
The specific aims are: 1) What roles do specific C-type lectins and endosome formation play in driving LNFPIII induction of alternative activation of APCs? 2) Determine if candidate signaling molecules and soluble factors are required for LNFPIII induced altemative activation of APCs?
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