Role of CCR8 and Other Chemokine Pathways in the Migration of Monocyte-derived Dendritic Cells to Lymph Nodes

Studying the influence of chemokine receptors (CCRs) on monocyte fate may reveal information about which subpopulations of monocytes convert to dendritic cells (DCs) and the migration pathways that they use. First, we examined whether prominent CCRs on different monocyte subsets, CCR2 or CX3CR1, mediated migration events upstream of the accumulation of monocyte-derived DCs in lymph nodes (LNs). Monocytes were labeled and traced by uptake of latex microspheres in skin. Unexpectedly, neither CCR2 nor CX3CR1 were required. However, absence of CCR2 led to an increased labeling of the minor Gr-1int monocyte population, and the number of latex+ DCs that emigrated to LNs was correspondingly increased. Characterization of Gr-1int monocytes revealed that they selectively expressed CCR7 and CCR8 mRNA in blood. CCR7 and CCR8 pathways were used by monocyte-derived DCs during mobilization from skin to LNs. The role of CCR8 in emigration from tissues also applied to human monocyte-derived cells in a model of transendothelial trafficking. Collectively, the data suggest that Gr-1int monocytes may be most disposed to become a lymphatic-migrating DCs. When these monocyte-derived DCs exit skin to emigrate to LNs, they use not only CCR7 but also CCR8, which was not previously recognized to participate in migration to LNs

Halted Lymphocyte Egress via Efferent Lymph Contributes to Lymph Node Hypertrophy During Hypercholesterolemia

Dyslipidemia is a central component of atherosclerosis and metabolic syndrome linked to chronic inflammation and immune dysfunction. Previously, we showed that hypercholesterolemic apolipoprotein E knock out (apoE−/−) mice exhibit systemic effects including skin inflammation and hypertrophic lymph nodes (LNs). However, the mechanisms accounting for LN hypertrophy in these mice remain unknown. Here, we show that hypercholesterolemia led to the accumulation of lymphocytes in LNs. We excluded that the increased number of lymphocytes in expanded LNs resulted from increased lymphocyte proliferation or entry into those LNs. Instead, we demonstrated that the egress of lymphocytes from the enlarged LN of apoE−/− mice was markedly decreased. Impairment in efferent lymphatic emigration of lymphocytes from LNs resulted from an aberrant expansion of cortical and medullary sinuses that became hyperplastic. Moreover, CCL21 was more abundant on these enlarged sinuses whereas lymph levels of sphingosine 1 phosphate (S1P) were decreased in apoE−/− mice. Normal LN size, lymphatic density and S1P levels were restored by reversing hypercholesterolemia. Thus, systemic changes in cholesterol can sequester lymphocytes in tissue draining LNs through the extensive remodeling of lymphatic sinuses and alteration of the balance between retention/egress signals leading to LN hypertrophy which subsequently may contribute to poor immunity. This study further illustrates the role of lymphatic vessels in immunity through the regulation of immune cell trafficking

Подбор оборудования для эксплуатации нефтяной скважины

Результат исследования: Был подобран погружной электроцентробежный насос, для данной нефтяной скважины, достоинствами которого является простота конструкции, так же унифицированная база запасных частей и комплектующих изделий отечественного производства.Result of the research: A submersible electric centrifugal pump was selected, for this oil well, whose advantages are simplicity of designs, as well as a unified base of spare parts and components of domestic production

Relation hôte-parasite au cours de la schistosomiase murine (contrôle de la réponse immune par le schistosome)

LILLE2-BU Santé-Recherche (593502101) / SudocSudocFranceF

Rapid MALDI-TOF mass spectrometry identification of <em>Leptospira</em> organisms: A reply

International audienc

Mapping of Hückel zigzag carbon nanotubes onto independent polyene chains: Application to periodic nanotubes

The electric polarizability and the spread of the total position tensors are used to characterize the metallic vs insulator nature of large (finite) systems. Finite clusters are usually treated within the open boundary condition formalism. This introduces border effects, which prevent a fast convergence to the thermodynamic limit and can be eliminated within the formalism of periodic boundary conditions. Recently, we introduced an original approach to periodic boundary conditions, named Clifford boundary conditions. It considers a finite fragment extracted from a periodic system and the modification of its topology into that of a Clifford torus. The quantity representing the position is modified in order to fulfill the system periodicity. In this work, we apply the formalism of Clifford boundary conditions to the case of carbon nanotubes, whose treatment results in a particularly simple zigzag geometry. Indeed, we demonstrate that at the Hückel level, these nanotubes, either finite or periodic, are formally equivalent to a collection of non-interacting dimerized linear chains, thus simplifying their treatment. This equivalence is used to describe some nanotube properties as the sum of the contributions of the independent chains and to identify the origin of peculiar behaviors (such as conductivity). Indeed, if the number of hexagons along the circumference is a multiple of three, a metallic behavior is found, namely a divergence of both the (per electron) polarizability and total position spread of at least one linear chain. These results are in agreement with those in the literature from tight-binding calculations