In the lamina propria of the intestine, the adaptive immune response is oriented towards tolerance and it involves suppression of Th1 cytokines such as IL-12 and activation of regulatory T cells that inhibit the proliferation of other T cells through production of IL-10 and TGFb1 [22] , [23] , [41] , [37] . Together with IECs, dendritic cells (DCs) interact with luminal bacteria [37] either through receiving M-cell delivered bacterial cargo or through extension of their own pseudopods across the IEC monolayer [42] , [43] , [43] . When we stimulated human PBMC-derived-dendriticcells (PBMC/DCs) with recombinant L. plantarum expressing the OspA lipoprotein, but not the unlipidated mutant, we observed that pro-inflammatory cytokines TNFa, IFNc and IL-6 were markedly upregulated. In addition, we observed an increase of anti-inflammatory cytokine IL-10. When we stimulated monocyte derived dendritic cells (MDDC) with L. plantarum expressing lipidated OspA, but not unlipidated OspA, we observed that proinflammatory cytokines TNFa and IL-12 were markedly upregulated. Here too, we observed an increase of anti-inflammatory cytokine IL-10. Differences in detection of cytokines in both assays can be explained by the fact that in the former (PBMC/DC) assay we expect to have a mixed population of monocyte derived dendritic cells, T cells, B cells and NK cells, and in the later (MDDC), we expect to have a relatively pure population of dendritic cells. These data indicate that recombinant OspA- expressing-L. plantarum stimulates the immune response via Th1/ Th2 cell mediated immunity and that, lipidation of the antigen in the delivery agent plays an active role in this response.