1,721,075 research outputs found
In vivo evidence for dendritic cell lysis by NK cells: Hints on improving cancer vaccines by targeting NK cell activation
No full textEMODERIVATO IN FORMA DI GEL COMPRENDENTE FIBRINA, PIASTRINE E LEUCOCITI
No full textLa presente invenzione riguarda la preparazione di un emoderivato in forma di gel, comprendente fibrina, piastrine, leucociti di matrice autologa ed un sostituto osseo, ed utilizzato nelle rigenerazione dei tessuti ossei, in ambito odontoiatrico. Tale emoderivato può essere modellato, compattato suturato e, quindi, applicato nella zona da trattare ottimizzando ed accelerando in forma naturale il processo di riparazione dei tessuti
Interactions between natural killer and dendritic cells during bacterial infections
No full textNatural killer (NK) cells represent a distinct lymphoid population
characterized by unique phenotypic and functional features. NK cells
were originally identified on a functional basis as this denomination was
assigned to lymphoid cells capable of lysing tumor cell lines in the absence
of prior stimulation in vivo or in vitro.1 Both their origin and the
mechanism(s) mediating their function remained mysterious until recently.
Regarding their origin, it has been shown that NK cells derive from
a precursor common to T cells and expressing the CD34þCD7þ phenotype.
In addition, functional NK cells can be obtained in vitro and in vivo
from (CD34þ) haematopoietic precursors isolated from several different
sources.26 The cell maturation in vitro has been shown to require
appropriate feeder cells and/or IL-15. The molecular mechanisms underlying
the ability of NK cells to discriminate between normal and tumor cells,
predicted by the ‘‘missing self hypothesis’’,7 have been clarified only
during the past decade. It has been shown that NK cells recognize MHCclass
I molecules through surface receptors delivering inhibitory, rather
than activating, signals. Accordingly, NK cells lyse target cells that have
lost (or express low amounts of) MHC class I molecules. This event
occurs frequently in tumors or in cells infected by some viruses such
as certain herpesviruses or adenoviruses. In addition to provide a first
line of defence against viruses, NK cells release various cytokines and
chemokines. These released cytokines can control bacterial spreading
but also induce or modulate inflammatory responses, hematopoiesis, and
control the growth and function of monocytes and granulocytes. Finally,
the functional links between NK and dendritic cells (DCs) have been
widely investigated in recent years and different studies have demonstrated
that reciprocal activations ensue upon NK/DC interactions. More
recently, the anatomical sites where these interactions take place have
been identified together with the related cell subsets involved.8 Remarkably,
there is now ‘‘in vivo’’ evidence that this cellular cross-talk occurring during the innate phase of the immune response against bacteria or bacterial
products can deeply affect the magnitude and the quality of the subsequent
adaptive response.
These new experimental evidences emphasize the relevance of the interplay between DCs and NK cells during bacterial infections
Dendritic Cell Interactions with NK Cells from Different Tissues
No full textIntroduction In recent years, it has been realized that innate lymphocytes do not act in isolation but potentiate their efficiency by interacting with each other, resulting even in the regulation of adaptive immune response. One such cross-talk exists between dendritic cells (DCs) and natural killer (NK) cells. Here, we summarize recent studies on which subsets of these two innate immune components
participate in this interaction, how it influences immune
responses, and to which extent similar stimuli are integrated
by DCs and NK cells during innate immunity.
Conclusion We suggest that this cross-talk should be harnessed by activating both of these innate leucocyte populations with new adjuvant formulations for immunotherapie
NK cell compartments and their activation by dendritic cells
No full textIntroduction In recent years, it has been realized that innate lymphocytes do not act in isolation but potentiate their efficiency by interacting with each other, resulting even in the regulation of adaptive immune response. One such cross-talk exists between dendritic cells (DCs) and natural killer (NK) cells. Here, we summarize recent studies on which subsets of these two innate immune components
participate in this interaction, how it influences immune
responses, and to which extent similar stimuli are integrated
by DCs and NK cells during innate immunity.
Conclusion We suggest that this cross-talk should be harnessed by activating both of these innate leucocyte populations with new adjuvant formulations for immunotherapies
Lymphoid progenitor cells generate powerful antigen-presenting dendritic cells along a monocyte-independent pathway
No full textIsolation and Analysis of Human Natural Killer Cell Subsets
No full textNatural killer (NK) cells were originally defined as mediators of spontaneous cytotoxicity
against virus-infected and tumor cells. In human peripheral blood, the majority of NK cells
can mediate cell lysis mainly through perforin and granzymes. It has been recently shown,
however, that the majority of NK cells in human secondary lymphoid organs are primarily
immunoregulatory by secreting cytokines immediately after activation and do not express perforin
and granzymes. Because lymph nodes (LN) harbor 40% and peripheral blood only 2% of all
lymphocytes in humans, this newly characterized NK cell compartment in LN and related tissues
probably outnumbers perforin+cytolytic NK cells in our body. Although human NK cell biology
has so far mainly studied peripheral blood NK cells, we have lately focused on human NK cells
harbored in lymphoid tissues and identified procedures for their optimal isolation as well as their
phenotypic and functional characterization
Biofilm Development and Approaches to Biofilm Inhibition by Exopolysaccharides
No full text: Bacteria biofilm consists of microorganisms, accounting for 5-35% of the biofilm volume, and of the extracellular matrix (65-95%), made of water (97%), proteins (2%), polysaccharides (1-2%) and nucleic acids (DNA/RNA, both <1%). The physiology of bacteria in the biofilms entails adaptive changes with expression of genes which are different from those translated in the planktonic state. While most of our applied knowledge on bacterial biology stems from the study in the planktonic state, an increasing interest is currently paid to bacterial behaviour as biofilm generators, as it is estimated that 65% of all bacterial infections are associated with bacterial biofilms. Infections of both upper and lower airways, bacterial endocarditis, chronic otitis media, urinary tract infections, periodontitis, ocular infections and chronic wound infections (including diabetic foot ulcer) are all associated with biofilm formation. The role of biofilm is also relevant in case of infections taking place on abiotic surfaces, as in the case of infections occurring on prostheses and several other medical devices. Here, we review current knowledge on biofilm formation and its impact on human infections, discussing recent means for its inhibition, with particular emphasis on an interesting anti-biofilm activity exerted by exopolysaccharides derived from marine strains of Bacillus licheniformis
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