Expression of the full-length B. burgdorferi OspA gene in E. coli, a Gram-negative bacteria, produces a protein that is processed posttranslationally by signal peptidase II and contains an attached lipid moiety. In E. coli this lipoprotein partitions mostly into the detergent phase following extraction with Triton X-114 [35] . As seen in E. coli, we show that in Gram-positive L. plantarum, the leader peptide also marks OspA for translocation or export across the cytoplasmic membrane given that wildtype OspA partitions to the detergent phase following extraction with Triton X-114, suggesting that it is lipidated. In contrast, the mutant OspA D17 , which lacks the cystein that is needed for the lipid moiety attachment, partitions mostly to the aqueous phase. This shift on the solubility of the mutant OspA D17 appears to be due to the lack of the lipid attachment, that makes the antigen more hydrophilic than the native lipidated OspA, and therefore the mutant appears to be unlipidated. It appears that OspA is indeed lipidated and localizes mostly at the membrane-cell wall interface. This observation is consistent with a previous study of Gram-positive Lactococcus spp. lipoprotein processing that found that lipid modification is predominantly required to retain proteins at the membrane cell-wall interface [36] . The intestinal immune system is the largest and the most complex part of the immune system [23] . Crosstalk occurs between the luminal microorganisms and the mucosal tissue, with intestinal epithelial cells (IECs) mediating this dialogue. Microbial invasion of the gut epithelium stimulates IECs to produce CXCchemokine ligand 8 (IL-8) and activate other pro-inflammatory pathways that in turn coordinate the innate immune response [37] . The absence of IL-8 secretion by IECs in the presence of recombinant L. plantarum is consistent with previous findings [38] , [39] , [40] and suggests that an oral vaccine based in L. plantarum expressing the OspA lipoprotein would not induce the local adverse inflammatory effects attributed to pathogenic bacteria.