Nucleation is a stochastic phenomenon and the probability of observing the critical nuclei formation is very low. Our aim is to enhance nucleation in the metastable zone enabling us to locate and control it.The first step is to determine the nucleation rate, and thus the nucleation behavior of the molecule studied. The two usual methods for determining nucleation rate are measuring induction time by direct counting/observation and direct determination of the steady-state rate of homogeneous nucleation.The second step consists in acting on nucleation, to control, locate and observe it. We develop unusual approaches, adding an external field to the crystallization conditions or using confinement. Ultrasounds reduce induction time and increase the number of crystals. The light irradiation induces nucleation by forming radicals. The electric field tends to localize the nucleation near one electrode depending on the polarity of the molecule studied in acting locally on the density of the solution. Lastly confinement was tested, and results indicate that this approach is very promising for controlling nucleation spatially and generate one single crystal per droplet.

Determining a reliable lattice energy is vital in the attachment energy approach for crystal habit prediction. In this paper, we present all experimental validation of the energies calculated with the soft-ware GENMOL by an indirect determination of the enthalpy of sublimation using the Knudsen effusion method.

The purpose of this work was to investigate (lie kinetic pathways in the phase solubility diagram of a cocrystallization process in solution. A cocrystal model composed of an active pharmaceutical ingredient (carbamazepine, CBZ) and a vitamin (nicotinamide, NCT) was selected. Batch experiments were performed in a stirred vessel. The process monitoring was carried out using ill Situ ATR-FTIR spectroscopy, which provided estimates of the Solute concentrations of both CBZ and NCT at different temperatures. In the working field, it was possible for CBZ/NCT cocrystals and CBZ crystals to develop separately or simultaneously. The concentration profiles plotted in the phase diagram showed the kinetic pathways of the cocrystallization process. Their analysis indicated which solid form was in Suspension and what the proportion of each solid phase was. Several experiments were in particular performed in the working domain leading to the invariant composition solution in equilibrium with both CBZ/NCT and CBZ crystals. Temporal information on the kinetic pathways and supersaturation levels is essential for finding the optimal operating conditions of the cocrystallization process.

Human CD4(+)CD25(+) regulatory T cells (Treg) play an essential role in the prevention of autoimmune diseases. However, the mechanisms of immune suppression and the spectrum of cells they target in vivo remain incompletely defined. In particular, although Treg directly suppress conventional T cells in vitro, they have been shown to inhibit the Ag-presenting functions of macrophage- and monocyte-derived dendritic cells (DC). We have now studied the maturation of human blood-derived myeloid DC and plasmacytoid DC activated with TLR ligands in the presence of Treg. Preactivated Treg suppressed strongly TLR-triggered myeloid DC maturation, as judged by the blocking of costimulatory molecule up-regulation and the inhibition of proinflammatory cytokines secretion that resulted in poor Ag presentation capacity. Although IL-10 played a prominent role in inhibiting cytokines secretion, suppression of phenotypic maturation required cell-cell contact and was independent of TGF-beta and CTLA-4. In contrast, the acquisition of maturation markers and production of cytokines by plasmacytoid DC triggered with TLR ligands were insensitive to regulatory T cells. Therefore, human Treg may enlist myeloid, but not plasmacytoid DC for the initiation and the amplification of tolerance in vivo by restraining their maturation after TLR stimulation.

In this contribution we present two cases of phase transitions, in which the ability to control the reproducible formation of the desired physical form requires a control of crystallization parameters and a deep understanding of the phase diagram.

The DCC (deleted in colon cancer) gene has a brain restricted high expression pattern. It encodes a transmembrane protein of the immunoglobulin superfamily identified as the netrin-1 receptor. It might be a member of the so called “brain-lymphoid” molecules, which control key cell surface events. To test this hypothesis we have assessed the DCC mRNA level in human normal and malignant myeloid and lymphoid cells. A high mRNA content has been observed only in mature B cells at the secreting or presecreting stage. Expression of DCC was also assessed in the anti-CD40 model of immunopoiesis. Activation of purified tonsillar B cells by anti-CD 40 antibody strongly increased the DCC mRNA level and this effect was dramatically enhanced by the association of IL-2 + IL-10, which is a potent and selective in vitro inducer of the B cell memory phenotype. In contrast no effect has been detected after activation of T cells by anti-CD3. These data suggest that the DCC encoded netrin receptor is involved in B cell immunopoiesis.

In this study, we describe human FDF03, a novel member of the Ig superfamily expressed as a monomeric 44-kDa transmembrane glycoprotein and containing a single extracellular V-set Ig-like domain. Two potential secreted isoforms were also identified. The gene encoding FDF03 mapped to chromosome 7q22. FDF03 was mostly detected in hemopoietic tissues and was expressed by monocytes, macrophages, and granulocytes, but not by lymphocytes (B, T, and NK cells), indicating an expression restricted to cells of the myelomonocytic lineage. FDF03 was also strongly expressed by monocyte-derived dendritic cells (DC) and preferentially by CD14+/CD1a− DC derived from CD34+ progenitors. Moreover, flow cytometric analysis showed FDF03 expression by CD11c+ blood and tonsil DC, but not by CD11c− DC precursors. The FDF03 cytoplasmic tail contained two immunoreceptor tyrosine-based inhibitory motif (ITIM)-like sequences. When overexpressed in pervanadate-treated U937 cells, FDF03 was tyrosine-phosphorylated and recruited Src homology-2 (SH2) domain-containing protein tyrosine phosphatase (SHP)-2 and to a lesser extent SHP-1. Like engagement of the ITIM-bearing receptor LAIR-1/p40, cross-linking of FDF03 inhibited calcium mobilization in response to CD32/FcγRII aggregation in transfected U937 cells, thus demonstrating that FDF03 can function as an inhibitory receptor. However, in contrast to LAIR-1/p40, cross-linking of FDF03 did not inhibit GM-CSF-induced monocyte differentiation into DC. Thus, FDF03 is a novel ITIM-bearing receptor selectively expressed by cells of myeloid origin, including DC, that may regulate functions other than that of the broadly distributed LAIR-1/p40 molecule.

We have identified a novel member of the calcium-dependent (C-type) lectin family. This molecule, designated DCIR (for dendritic cell (DC) immunoreceptor), is a type II membrane glycoprotein of 237 aa with a single carbohydrate recognition domain (CRD), closest in homology to those of the macrophage lectin and hepatic asialoglycoprotein receptors. The intracellular domain of DCIR contains a consensus immunoreceptor tyrosine-based inhibitory motif. A mouse cDNA, encoding a homologous protein has been identified. Northern blot analysis showed DCIR mRNA to be predominantly transcribed in hematopoietic tissues. The gene encoding human DCIR was localized to chromosome 12p13, in a region close to the NK gene complex. Unlike members of this complex, DCIR displays a typical lectin CRD rather than an NK cell type extracellular domain, and was expressed on DC, monocytes, macrophages, B lymphocytes, and granulocytes, but not detected on NK and T cells. DCIR was strongly expressed by DC derived from blood monocytes cultured with GM-CSF and IL-4. DCIR was mostly expressed by monocyte-related rather than Langerhans cell related DC obtained from CD34+ progenitor cells. Finally, DCIR expression was down-regulated by signals inducing DC maturation such as CD40 ligand, LPS, or TNF-alpha. Thus, DCIR is differentially expressed on DC depending on their origin and stage of maturation/activation. DCIR represents a novel surface molecule expressed by Ag presenting cells, and of potential importance in regulation of DC function.