Human dendritic cells pulsed with specific lipopeptides stimulate autologous antigen-specific T cells without the addition of exogenous maturation factors

• Published in: Journal of viral hepatitis Vol. 15; no. 10; pp. 761 - 772
• Main Authors: Jones, K. L., Brown, L. E., Eriksson, E. M. Y., Ffrench, R. A., Latour, P. A., Loveland, B. E., Wall, D. M., Roberts, S. K., Jackson, D. C., Gowans, E. J.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-10-2008
• Subjects: Adult; Amino Acid Sequence; Cell Differentiation; closed system; Coculture Techniques; Culture Media, Serum-Free; dendritic cells; Dendritic Cells - cytology; Dendritic Cells - drug effects; Dendritic Cells - immunology; Epitopes, T-Lymphocyte - chemistry; free medium; hapatitis C virus; Humans; Immunologic Memory; lipopeptides; Lipoproteins - chemical synthesis; Lipoproteins - chemistry; Lipoproteins - immunology; Lymphocyte Activation; Male; Middle Aged; Monocytes - cytology; Peptides - chemical synthesis; Peptides - chemistry; Peptides - immunology; serum; T-Lymphocytes - immunology; T-Lymphocytes, Cytotoxic - immunology
• ISSN: 1352-0504; 1365-2893
• DOI: 10.1111/j.1365-2893.2008.01003.x

Serum‐free culture conditions to generate immature human monocyte‐derived DC (Mo‐DC) were optimized, and the parameters that influence their maturation after exposure to lipopeptides containing CD4+ and CD8+ T‐cell epitopes were examined. The lipopeptides contained a single CD4+ helper T‐cell epitopes, one of a number of human leucocyte antigen (HLA)‐A2‐restricted cytotoxic T‐cell epitope and the lipid Pam2Cys. To ensure complete maturation of the Mo‐DC, we examined (i) the optimal lipopeptide concentration, (ii) the optimal Mo‐DC density and (iii) the appropriate period of exposure of the Mo‐DC to the lipopeptides. The results showed that a high dose of lipopeptide (30 μm) was no more efficient at upregulating maturation markers on Mo‐DC than a low dose (6 μm). There was an inverse relationship between Mo‐DC concentration and the mean fluorescence intensity of maturation markers. In addition, at the higher cell concentrations, the chemotactic capacity of the Mo‐DC towards a cognate ligand, CCL21, was reduced. Thus, high cell concentrations during lipopeptide exposure were detrimental to Mo‐DC maturation and function. The duration of exposure of Mo‐DC to the lipopeptides had little effect on phenotype, although Mo‐DC exposed to lipopeptides for 48 rather than 4 h showed an increased ability to stimulate autologous peripheral blood mononuclear cells to release interferon‐γ in the absence of exogenous maturation factors. These findings reveal conditions for generating mature antigen‐loaded DC suitable for targeted immunotherapy.