Dendritio cells generated in the presence of vitamin D3 and stimulated with lipopolysaccharide seorete IL-8, IL-1β, IL-10 and induce relatively low levels of CD4+CD25hiFoxp3+T cells

Introduction: Vitamin D3 (VD3) has been described as a modulator of immune system cells, including dendritic cells (DC). Previous studies have shown its importance in in vitro generation of tolerogenic DC, which have a similar function and phenotype to that of CD141 dermal DCs that produce IL-10 and induce (LTreg) CD4+ T regulator cells. Objective: This paper presents a study that compares the phenotype and cytokines produced by DC generated in presence and absence of VD3, which were matured with lipopolysaccharide (LPS), and their ability to induce LTreg from naive allogeneic CD4+ T cells. Materials and methods: In order to compare them, peripheral blood mononuclear cells were isolated to select monocytes CD14+ T cells and differentiate them in vitro from DC in the presence and absence of VD3, and to mature them with LPS. Phenotype and cytokine levels were also analyzed in the culture supernatants. Dendritic cells were then co-cultured with naive allogeneic CD4+ T cells and the frequencies of LTreg were determined (naive-activated). Results: The results showed that unstimulated DC generated with VD3 kept the CD14. When activated with LPS, they expressed lower levels of C83, CD83 and CD86; HLA-DR; higher amounts of IL-1 beta, IL-8, IL-10, and tended to lessen IL-6, IL-12p70 and TGF-beta 1, compared to DCs not treated with VD3. The frequency of naive LTreg was similar, although immature DC generated with VD3 tended to induce activated LTregs. Conclusion: Based on these results, it is possible to conclude that DCs generated with VD3 and treated with LPS presented a 'semi-mature' phenotype, and were able to secrete pro-inflammatory and anti-inflammatory cytokines. Besides, they did not increase their capacity to promote the polarization of naive allogenic CD4+ T cells towards LTregs.