Helminth-conditioned dendritic cells prime CD4+ T cells to IL4 production in vivo (IRC5P.469)

Abstract

Abstract Dendritic cells are critical for the initiation of immune responses, however, their role in priming IL4-producing Th2 cells is controversial and remains an area of intense investigation. We found that after skin injection of the nematode parasite Nippostrongylus brasiliensis (Nb), a strong inducer of Th2 responses, Nb material is taken up by a population of dermal dendritic cells in lymph node, and that this population is necessary and sufficient for IL4 priming. Blocking the migration of dermal dendritic cells to the lymph node also prevented the priming of IL4-producing cells, and chicken ovalbumin (OVA)-loaded dDC from Nb-treated mice were sufficient to sensitize OVA-specific CD4+ T cells to IL4 production in vivo. Nb-loaded dermal dendritic cells were CD11b+, CD326neg, CD103neg, PDL2hi and IRF4+, and modestly upregulated expression of OX40L. However, OX40L and TSLP were not required for Th2 priming. Thus, our data suggest that the appropriate stimuli can induce DC to express the unique signals that direct CD4+ T cells to Th2 differentiation.