Differential regulation of interleukin 12 and interleukin 23 production in human dendritic cells.

We analyzed interleukin (IL) 12 and IL-23 production by monocyte-derived dendritic cells (mono-DCs). Mycobacterium tuberculosis H37Rv and zymosan preferentially induced IL-23. IL-23 but not IL-12 was efficiently induced by the combination of nucleotide-binding oligodimerization domain and Toll-like receptor (TLR) 2 ligands, which mimics activation by M.

IFN-gamma and R-848 dependent activation of human monocyte-derived dendritic cells by Neisseria meningitidis adhesin A.

A soluble recombinant form of Neisseria meningitidis adhesin A (NadADelta351-405), proposed as a constituent of anti-meningococcal B vaccines, is here shown to specifically interact with and immune-modulate human monocyte-derived dendritic cells (mo-DCs). After priming with IFN-gamma and stimulation with NadADelta351-405, mo-DCs strongly up-regulated maturation markers CD83, CD86, CD80, and HLA-DR, secreted moderate quantities of TNF-alpha, IL-6, and IL-8, and produced a slight, although significant, amount of IL-12p70. Costimulation of mo-DCs with NadADelta351-405 and the imidoazoquinoline drug R-848, believed to mimic bacterial RNA, increased CD86 in an additive way, but strongly synergized the secretion of IL-12p70, IL-1, IL-6, TNF-alpha, and MIP-1alpha, especially after IFN-gamma priming.

Nitrogen substitution modifies the activity of cytisine on neuronal nicotinic receptor subtypes.

Cytisine very potently binds and activates the alpha 3 beta 4 and alpha 7 nicotinic subtypes, but only partially agonises the alpha 4 beta 2 subtype. Although with a lower affinity than cytisine, new cytisine derivatives with different substituents on the basic nitrogen (CC1-CC8) bind to both the heteromeric and homomeric subtypes, with higher affinity for brain [3H]epibatidine receptors. The cytisine derivatives were tested on the Ca(2+) flux of native or transfected cell lines expressing the rat alpha 7, or human alpha 3 beta 4 or alpha 4 beta 2 subtypes using Ca(2+) dynamics in conjunction with a fluorescent image plate reader.

Reciprocal activating interaction between natural killer cells and dendritic cells.

We analyzed the interaction between human peripheral blood natural killer (NK) cells and monocyte-derived immature dendritic cells (DC). Fresh NK cells were activated, as indicated by the induced expression of the CD69 antigen, and their cytolytic activity was strongly augmented by contact with lipopolysaccharide (LPS)-treated mature DC, or with immature DC in the presence of the maturation stimuli LPS, Mycobacterium tuberculosis or interferon (IFN)-alpha. Reciprocally, fresh NK cells cultured with immature DC in the presence of the maturation stimuli strongly enhanced DC maturation and interleukin (IL)-12 production.