The antimicrobial peptide hLF1-11 drives monocyte-dendritic cell differentiation toward dendritic cells that promote antifungal responses and enhance Th17 polarization.

The hLF1-11 peptide comprising the first 11 N-terminal residues of human lactoferrin exerts antimicrobial activity in vivo, enhances the inflammatory response of monocytes and directs monocyte-macrophage differentiation toward cells with enhanced antimicrobial properties. In this study, we investigated the effects of hLF1-11 on human monocyte-dendritic cell (DC) differentiation and subsequent T cell activation. Results revealed that - compared to control (peptide-incubated) DCs - hLF1-11-differentiated DCs displayed enhanced expression of HLA class II antigens and dectin-1, and increased phagocytosis of Candida albicans. In addition, hLF1-11-differentiated DCs produced enhanced amounts of reactive oxygen species, IL-6 and IL-10, but not IL-12p40 and TNF-α, upon stimulation with C. albicans. Moreover, 6-day-cultured hLF1-11-differentiated DCs and control (peptide-incubated) DCs that had been stimulated with a Th17-inducing mix of antigens (including C. albicans) for 24 h were cocultured with autologous CD4+ T cells for 72 h and then the levels of IL-10, IL-17 and IFN-γ production and the percentage of cytokine-producing T cells were assessed. The results revealed that the hLF1-11-differentiated DCs induced an enhanced IL-17, but reduced IFN-γ, production by T cells as compared to control (peptide-incubated) DCs. Collectively, the hLF1-11 peptide drives monocyte-DC differentiation toward DCs that promote antifungal responses and enhance Th17 polarization.