Therapeutic Liposomal Vaccines for Dendritic Cell Activation or Tolerance.

Dendritic cells (DCs) are paramount in initiating and guiding immunity towards a state of activation or tolerance. This bidirectional capacity of DCs sets them at the center stage for treatment of cancer and autoimmune or allergic conditions. Accordingly, many clinical studies use ex vivo DC vaccination as a strategy to boost anti-tumor immunity or to suppress immunity by including vitamin D3, NF-κB inhibitors or retinoic acid to create tolerogenic DCs. As harvesting DCs from patients and differentiating these cells in vitro is a costly and cumbersome process, in vivo targeting of DCs has huge potential as nanoparticulate platforms equipped with activating or tolerogenic adjuvants can modulate DCs in their natural environment. There is a rapid expansion of the choices of nanoparticles and activation- or tolerance-promoting adjuvants for a therapeutic vaccine platform. In this review we highlight the most recent nanomedical approaches aimed at inducing immune activation or tolerance via targeting DCs, together with novel fundamental insights into the mechanisms inherent to fostering anti-tumor or tolerogenic immunity.

Herbal medicine IMOD suppresses LPS-induced production of proinflammatory cytokines in human dendritic cells.

Traditional medicines that stimulate or modulate the immune system can be used as innovative approaches to treat immunological diseases. The herbal medicine IMOD has been shown to strongly modulate immune responses in several animal studies as well as in clinical trials. However, little is known about the mechanisms of IMOD to modulate immunity. Here we have investigated whether IMOD modulates the immunological function of human dendritic cells (DCs). IMOD alone did not induce DC maturation nor production of cytokines. Notably, IMOD decreased the production of pro-inflammatory cytokines IL-6, IL-12 p70, and TNFα by LPS-activated DCs at both mRNA and protein levels in a dose dependent manner. In contrast, treatment with IMOD did not affect LPS induced-production of the anti-inflammatory cytokine IL-10. Furthermore, IMOD inhibited T cell activation/proliferation by LPS-treated DCs and skewed T-cells responses toward the T helper type 2 polarization. These data strongly indicate that IMOD has a potent immunomodulatory ability that affects TLR signaling and thereby modulates DC function. Insight into the immunomodulatory effect of herbal medicine IMOD may provide innovative strategies to affect the immune system and to help combat various diseases.

Mutz-3-derived Langerhans cells are a model to study HIV-1 transmission and potential inhibitors.

Sexual transmission is the primary route of HIV-1 infection, and DC subsets are thought to be involved in viral dissemination to T cells. In the genital mucosa, two main subsets of DCs are present: epithelial LCs capture and degrade HIV-1 through C-type lectin Langerin, whereas subepithelial DCs express DC-SIGN, which facilitates HIV-1 transmission to T cells. As there is currently no HIV-1 vaccine available, microbicides provide an alternative strategy to limit HIV-1 spread. However, research into the function of LCs is hampered by the low availability and donor differences. Here, we set out to investigate whether LCs derived from the Mutz-3 cell line (Mu-LCs) provide a valuable tool to investigate the role of LCs in HIV-1 transmission and identify suitable potential microbicides. We demonstrate that Mu-LCs phenotypically resemble human primary LCs; Mu-LCs do not transmit HIV-1 efficiently, and inhibition of Langerin enhances HIV-1 transmission to T cells. We show that carbohydrate structures blocking DC-SIGN but not Langerin are potential microbicides, as they prevent HIV-1 transmission by DCs but do not affect the antiviral function of LCs. Therefore, Mu-LCs are a suitable model to investigate the role of LCs in HIV-1 transmission and to screen potential microbicides.