RESUMO
Chlorella polysaccharides have been gaining increasing attention because of their high yield from dried Chlorella powder and their remarkable immunomodulatory activity. In this study, the major polysaccharide fraction, CPP-3a, in Chlorella pyrenoidosa, was isolated, and its detailed structure was investigated by analyzing the low-molecular-weight product prepared via free radical depolymerization. The results indicated that CPP-3a with a molecular weight of 195.2 kDa was formed by â2)-α-L-Araf-(1â, â2)-α-D-Rhap-(1â, â5)-α-L-Araf-(1â, â3)-ß-D-Glcp-(1â, â4)-α-D-Glcp-(1â, â4)-α-D-GlcpA-(1â, â2,3)-α-D-Manp-(1â, â3,4)-α-D-Manp-(1â, â3,4)-ß-D-Galp-(1â, â3,6)-ß-D-Galp-(1â, and â2,3,6)-α-D-Galp-(1â residues, branched at C2, C3, C4, or C6 of α/ß-D-Galp and α-D-Manp, and terminated by α/ß-L-Araf, α-L-Arap, α-D-Galp, and ß-D-Glcp. Biological assays showed that CPP-3a significantly altered the dendritic morphology of immature dendritic cells (DCs). Enhanced CD80, CD86, and MHC I expression on the cell surface and decreased phagocytic ability indicated that CPP-3a could induce the maturation of DCs. Furthermore, CPP-3a-stimulated DCs not only stimulated the proliferation of allogeneic naïve CD4+ T cells and the secretion of IFN-γ, but also directly stimulated the activation and proliferation of CD8+ T cells through cross-antigen presentation. These findings indicate that CPP-3a can promote human DC maturation and T-cell stimulation and may be a novel DC maturation inducer with potential developmental value in DC immunotherapy.
Assuntos
Chlorella , Humanos , Linfócitos T CD8-Positivos , Polissacarídeos/química , Peso Molecular , Células DendríticasRESUMO
Dendritic cell (DC)-based immunotherapies have been utilized for the treatment of numerous diseases. However, the conventional generation strategies of DCs in vitro require 7 days and these DCs showed an unsatisfactory function, which prompted us to explore new approaches. We found that in vitro culture of human CD14+ cells, in the medium containing granulocyte-macrophage colony-stimulating factor (GM-CSF), interleukin (IL)-4, as well as interferon ß (IFN-ß) for 48 h, followed by the maturation stimuli of IL-1ß and poly I:C for another 24 h can be differentiated into high cross-presentation ability DCs (G4B-DCs). These DCs express high levels of CD11c, CD86, and HLA-DR, producing a high level of tumor necrosis factor α (TNF-α). Of note, compared with the conventional DCs, G4B-DCs showed a higher ability to promote allogeneic naïve CD4+ T cell and CD8+ T cell proliferation and interferon (IFN)-γ production. These DCs also have the remarkable ability to induce Flu-M1-specific CD8+ T cells. In addition, we found that these G4B-DCs express partially the cDC1 phenotype. These data indicate that G4B-DC is unique and may provide a relatively rapid alternative method for potential clinical use.