Next, we treated PBMCs with GM-CSF and IL-4 to derive the monocyte population into immature dentritic cells (PBMC/ DCs), and we investigated the cytokine production of human PBMC/DCs co-cultured with UV-killed recombinant L. plantarum expressing either lipidated OspA (LpA), the mutant unlipidated OspA (LpA D17 ) or the control (Lp). The amount of pro-inflammatory cytokines TNFa, IL-12, IFNc and IL-6, and anti-inflammatory cytokine IL-10 was quantified by ELISA (Fig. 6) . As compared to the control, LpA induced TNFa by 9 fold, IL-12 by 3 fold, IFNc by 4 fold and IL-6 by 10 fold (Fig. 6A, 6B, 6C and 6D) . Additionally, anti-inflammatory cytokine IL-10 was 7 fold upregulated by stimulation with recombinant L. plantarum expressing lipidated (LpA) as compared to the control (Lp) (Fig. 6E) . Compared to LpA, the mutant L. plantarum expressing the unlipidated OspA (LpA D17 ) induced significantly less TNFa, IL-12, IFNc, IL-6 and IL-10 ( Fig. 6A, 6B, 6C, 6D and 6E ). Differences between LpA and LpA D17 are statistically significant (*p,0.001 and **p,0.02). Further, compared to the control (Lp), LpA D17 induced TNFa, IL-6 and IL-10 (p,0.001). LPS was used as a positive control and upregulated secretion of all cytokines tested (data not shown). In order to dissect these results, we further purified monocytes by MACS to derive MDDC and analyzed cytokine production after stimulation (Fig. 7) . As expected, we determined that LpA induced higher production of proinflammatory cytokines TNFa (17 fold upregulated), IL-12 (,4 fold upregulated) and IL-6 (1-2 fold upregulated) as compared to the control (Lp) (Fig. 7A, 7B and 7D, respectively). There was no production of IFNc by monocyte derived dendritic cells (Fig. 7C) . Compared to LpA, the mutant L. plantarum expressing the unlipidated OspA (LpA D17 ) abrogated this response as seen by the decreased production of TNFa, IL-12 and IL-6 ( Fig. 7A, 7B and 7D) . Additionally, IL-10 was ,2-3 fold upregulated after stimulation with recombinant L. plantarum expressing lipidated (LpA) and the mutant appeared to impair this response (Fig. 7E) . Differences between LpA and LpA D17 are statistically significant (*p,0.05 and **p,0.001).