Besides their role in destruction of altered self-cells, NK cells have been shown to potentiate T-cell responses by interacting with DC. To take advantage of NK-DC crosstalk in therapeutic DC-based vaccination for infectious diseases and cancer, it is essential to understand the biology of this crosstalk. We aimed to elucidate the in vitro mechanisms responsible for NK-cell recruitment and activation by DC during infection. To mimic bacterial infection, DC were exposed to a membrane fraction of Klebsiella pneumoniae, which triggers TLR2/4. DC matured with these bacterial fragments can actively recruit NK cells in a CCR5-dependent manner. An additional mechanism of DC-induced NK-cell recruitment is characterized by the induction of CCR7 expression on CD56 dim CD16 1 NK cells after physical contact with membrane fraction of K. pneumoniae-matured DC, resulting in an enhanced migratory responsiveness to the lymph node-associated chemokine CCL19. Bacterial fragment-matured DC do not only mediate NK-cell migration but also meet the prerequisites needed for augmentation of NK-cell cytotoxicity and IFN-c production, the latter of which contributes to Th1 polarization.Key words: CCR5 . CCR7 . NK-DC interaction . Th1 polarization Supporting Information available online Introduction NK cells are important effector cells in the innate immune response against virally infected or malignantly transformed cells and their cytotoxicity is regulated by a delicate balance of inhibitory and activating signals [1]. Recent studies suggest that the interplay between NK cells and DC, the specialized antigenpresenting cell of the innate immune system [2], is critical in shaping the adaptive immune response [3]. This concept originates from several lines of evidence including: the discovery of NK cells colocalizing with DC in the T-cell areas of lymph nodes [4,5], the coupling of NK-cell recruitment to lymph nodes à These authors contributed equally to this work. 3138with the induction of more potent Th1 skewing [3], and the identification of NK-cell subpopulations with helper properties [6]. Although the exact mechanisms of NK-DC interaction remain to be elucidated, increasing evidence supports the importance of bidirectional NK-DC crosstalk [7,8].On the one hand, NK-DC crosstalk is characterized by the capacity of activated NK cells to induce DC maturation with elevated IL-12p70 production and subsequently an increased capacity to induce Th1 and CTL responses [9]. This NK-induced DC maturation depends at least in part on soluble factors such as and as well as on engagement of the natural cytotoxicity triggering receptor 30 [12]. Moreover, NK cells control the quality of the adaptive immune response by natural cytotoxicity triggering receptor 30-mediated lysis of immature or inadequately matured DC [13], enabling only fully mature DC to migrate into lymph nodes and subsequently prime T cells. On the other hand, DC are able to induce NK-cell proliferation, augmentation of cytotoxicity and cytokine secretion [8]. The DC-induced modulati...

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Klebsiella pneumoniae OmpA, the 40-kDa major protein of the outer membrane, was cloned and expressed in Escherichia coli. The recombinant protein was produced intracellularly in E. coli as inclusion bodies. Fusion of a short peptide to the N-terminus of native P40 facilitated high-level expression of the recombinant protein. Purified recombinant P40 was analyzed to verify purity and structural integrity. The molecular mass of purified recombinant P40 determined by electrospray mass spectrometry was 37 061 Da, in agreement with the theoretical mass deduced from the DNA sequence. Specific proliferation of recombinant-P40-primed murine lymph node cells in response to recombinant P40 stimulation in vitro indicated the presence of a T-cell epitope on recombinant P40. The induction of high serum antibody titers to a synthetic peptide derived from the attachment protein G of the respiratory syncytial virus when chemically coupled to recombinant P40 indicated that the protein had potent carrier properties. OmpA [20, 21] have been demonstrated to mediate expression of gram-negative bacteria, present at about 10 5 copies/cell. It is believed to occur in a monomeric form in its native state. A of peptides on the surface of live enterobacterial vectors. OmpC, the outer-membrane protein complex of Neisseria meningitidis, typical feature of OmpA is that it can be modified by heat: the mobility of Escherichia coli OmpA on SDS/PAGE decreases has been shown to be effective in humans as a conjugate vaccine with Haemophilus influenzae, pneumococcal and meningococcal when it is heated in the presence of SDS [1]. OmpA is highly conserved among gram-negative bacteria and is thought to con-capsular polysaccharides [22Ϫ25]. Other clinically useful carrier proteins have been derived from bacteria: diphteria and tetanus sist of two domains. The N terminus, including amino acid residues 1Ϫ170, forms a membrane-spanning domain and crosses toxoids are both successfully used in conjugated H. influenzae vaccines to transform the capsular polysaccharide, which is a Tthe outer membrane eight times in antiparallel β-strands, leading to a typical amphiphilic β-barrel [2Ϫ4]. The C-terminal moiety independent antigen, into a T-dependent antigen [26]. KeywordsIn this paper we describe the expression and production in of the protein is thought to be periplasmic [5]. The protein seems to be multifunctional. In addition to non-physiological functions, E. coli and purification of Klebsiella pneumoniae OmpA [27].Using various analytical criteria, the purity and structural integsuch as serving as a receptor for phages and colicins [6], it serves as a mediator in F-factor-dependent conjugation [7]. It is rity of the protein were evaluated. We demonstrate the presence of at least one T-cell epitope on the molecule and its potential also required for the structural integrity of the outer membrane and the generation of normal cell shape [8]. The capacity to use as a carrier protein for conjugated peptides. The immunological carrier properties of the recombin...

What ' s known on the subject? and What does the study add? Pervasive infl ammatory infi ltrates, mainly composed of chronically activated T cells and monocytes/macrophages, have been observed in benign prostatic hyperplasia (BPH). Permixon ® , a hexanic lipidosterolic extract of Serenoa repens (hexanic LSESr) used to treat urinary dysfunction in BPH patients, has anti-infl ammatory activities. This paper provides new insights into the anti-infl ammatory properties of Permixon ® . We report that hexanic LSESr inhibits early steps of leukocyte infi ltration in vitro by downregulating MCP-1/CCL2 and VCAM-1 expression.

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