We have studied the immuno-physiology of rat and mouse intestinal dendritic cells. We have used a known adjuvant, E. coli heat-labile toxin (Etx) and a potential adjuvant R-848, a small TLR7/8 ligand.

For a transcriptional profiling of dendritic cells, DC were stimulated with PolyI:C, pretreated or not with PP2, and microarray analysis was performed.

We examined whether plasmacytoid pDC are infected and/or activated by MTb, and whether they play a role in regulating bacterial clearance during acute MTb infection and if so how. We have compared these DC with myeloid DC and macrophages with respect to MTb infection.

These DC pulsed with MAGE-A3, gp100, NA17 and tyrosinase were used for vaccination of melanoma patients.

PBMC were isolated from buffy coat. Subsequently, monocytes were isolated and differentiated into dendritic cells.

PBMC are Leukapheresis derived and are loaded with peptide pools, each consisting of 10 15-mers, which overlap with 11 aminoacids.

We have analyzed the uptake, conservation and cross-presentation of the model antigen OVA after Fc receptor-mediated uptake by DC. We found that MHC class I presentation is relatively short-lived in contrast to MHC class II. However, CD8 cross-priming capacity of OVA-loaded DC was functionally retained for many days, while peptide-pulsed DC had lost their priming capacity after 24 hours.

Perforine expressing T cells were observed in human Hemato-Lymphoid System Rag2-/-gc-/- mice after being infected with EBV and mounting an immune response. They infiltrated in B cell infected areas in lymphoid organs in situ.

We have demonstrated that the NADPH oxidase NOX2 is recruited to DC early phagosomes mediating a sustained production of low levels of reactive oxygen species and causing a maintained alkalynization of the phagosomal lumen. DCs lacking NOX2 show increased antigen degradation due to an enhanced phagosome acidification. As a result, the efficiency of in vitro and in vivo antigen cross presentation is significantly reduced in NOX2-deficient DCs.

We have analyzed the uptake, conservation and cross-presentation of the model antigen OVA after Fc receptor-mediated uptake by DC. We found that MHC class I presentation is relatively short-lived in contrast to MHC class II. However, CD8 cross-priming capacity of OVA-loaded DC was functionally retained for many days, while peptide-pulsed DC had lost their priming capacity after 24 hours.

We have studied the immuno-physiology of rat and mouse intestinal dendritic cells. We have used a known adjuvant, E. coli heat-labile toxin (Etx) and a potential adjuvant R-848, a small TLR7/8 ligand.

When we tested in therapeutic tumor experiments with OVA+ melanoma cells, direct administration of lentiviral vectors slowed down tumor growth to a comparable extent with the highest dose of ex vivo transduced DC.

The group completed the measurements of murine dendritic cell subsets and established an in-depth proteomic map of them. These preliminary results show more than 4500 identified proteins in each subset. All of the known markers like CD11c, CD11b, DEC-205, Langerin, etc. were found according to their differential expression pattern.

These multipeptide loaded cytokine matured moDC +/- CD40L activation were used for the DERMA-ER-DC 04 trial.

The moDCs are used in the DERMA-ER-DC 05 trial. They are multipeptide loaded cytokine matured moDC + prior Treg elimination by 3x ONTAK treatment [5µg/kg]. 8 patients are enrolled and receive this substance.

We found that CD8alpha- DC produced undetectable levels of IL-12p70 upon stimulation with CpG.

We found that BM-myeloid and splenic CD8alpha+ DC produced at least fivefold less IL-12p70 than plasmacytoid pDC responding to both CpG and the TLR-7 ligand R848.

These cells were primed in vitro by engineered antigen-presenting cells and used to investigate the effect of environmental factors on development of high affinity cytotoxic T lymphocytes (CTL).

Injection of lentiviral vectors activated OVA-specific CD4+ T cells and this CD4 help was shown to be necessary for an adequate primary and memory CTL response.

Stimulation of Mycobacterium tuberculosis (MTb)-antigen specific T cells ex-vivo in the presence of anti-IL-10 antibodies results in their increased proliferation and IFN- production.