Pathogen-derived products have the capacity to induce maturation of bone marrow-derived dendritic cells (BMDCs)into populations of effectors cells that polarize Th cells toward Th1 or Th2 phenotype via different mechanisms. Since those mechanisms are not entirely clear for helminths, and almost completely unknown for Trichinella spiralis(TS), we started an investigation of the effects of TS antigens (four different antigens isolated from all three life-cycle stages of parasite)on maturation of BMDCs and their potential to present TS antigens. The expression of MHC class II, costimulatory molecules CD86, CD54, IL-10 and IL-12p70 cytokine production were measured after 2 days of BMDCs cultivation with TS antigens. While parasitic antigens did not significantly alter the expression of MHC II, most of them, except crude muscle larvae antigens, up-regulated the expression of costimulatory molecules. BMDCs, primed with all TS antigens, released increased amounts of IL-10 and decreased amounts of IL-12p70. BMDCs, primed with TS antigens, induced significant proliferation of syngeneic TS sensitized lymph nodes cells and also stimulated the production of IL-4 by T cells purified from of TS infected DA rats. The results indicate that TS stimulated BMDCs leads to the polarization of the immune response towards regulatory and Th2 type.