Levilactobacillus brevis surface layer protein B promotes liposome targeting to antigen-presenting cells in Peyer's patches.

Liposome targeting by conjugation with specific ligands and cross-linking reagents is an attractive strategy for active drug delivery. Here, we demonstrated the potential of surface layer protein (Slp) B from Levilactobacillus brevis JCM 1059 as a specific ligand to antigen-presenting cells (APCs) in Peyer's patches. L. brevis JCM 1059 SlpB-coated liposomes (SlpB-LPs) showed higher resistance to various pH values and bile acids compared to non-coated liposomes (LPs). SlpB-LP showed a significantly higher uptake into dendritic cell-like differentiated THP-1 cells than LP did. The SlpB-LP-conjugated α-galactosylceramide (αGalCer) promoted the production of IL-12 (p40) and TNF-α by THP-1 cells. Furthermore, SlpB-LP showed significantly higher delivery efficiency into APCs underlaying microfold (M) cells in Peyer's patches after oral administration in BALB/c mice and enhanced IL-12 production when αGalCer was conjugated to SlpB-LP. In conclusion, the present study demonstrates the therapeutic potential of SlpB-coated LP to deliver immunomodulatory components to the gut immune system.