Hepatocellular expression of lymphocyte function—associated antigen 3 in chronic hepatitis

T lymphocyte-mediated cytolytic immune reactions are considered a major cause of hepatocyte injury in chronic viral and autoimmune hepatitis. To further investigate local immune responses, we studied the expression of lymphocyte antigens and cell-cell interaction molecules known to be involved in effector-target cell interactions by light and electron microscopy in liver biopsy specimens from patients with chronic viral and autoimmune hepatitis. CD8+ lymphocytes were found to be the predominant population of cells in the inflammatory infiltrate in chronic hepatitis B and non-A, non-B hepatitis. In contrast, CD4+ cells constituted a comparably higher proportion of cells and were more numerou…

The Anaphylatoxic Peptide C3a of Guinea Pig Complement

Abstract Highly purified guinea pig C3a was obtained after specific cleavage of isolated C3 by the alternative pathway enzyme VF-B in a one step procedure. It turned out to be a low molecular weight peptide with basic character (M.W. 9500; isoelectric point above 9.4). C3a represents an antigenetic determinant of its own in the native C3 molecule, different from the B determinant. Guinea pig C3a is resistant to 100°C for 10 minutes. Its smooth muscle contracting activity can be destroyed by trypsin and carboxypeptidase B. These findings indicate that guinea pig C3a is quite similar to human C3a.

The extent of HLA-DR expression on HLA-DR+Tregs allows the identification of patients with clinically relevant borderline rejection

Regulatory T cells (Tregs) were shown to be involved into the pathogenesis of acute rejection after transplantation. The suppressive activity of the total regulatory T cell pool depends on its percentage of highly suppressive HLA-DR(+) -Treg cells. Therefore, both the suppressive activity of the total Treg pool and the extent of HLA-DR expression of HLA-DR(+) -Tregs (MFI HLA-DR) were estimated in non transplanted volunteers, patients with end-stage renal failure (ESRF), healthy renal transplant patients with suspicion on rejection, due to sole histological Bord-R or sole acute renal failure (ARF), and patients with clinically relevant borderline rejection (Bord-R and ARF). Compared to patie…

A distinct subset of HLA-DR+-regulatory T cells is involved in the induction of preterm labor during pregnancy and in the induction of organ rejection after transplantation.

Regulatory T cells (Tregs) are known to suppress alloimmune responses during pregnancy and post organ transplantation. We demonstrate that a distinct subset of FoxP3(+)DR(+)-Tregs among the total CD4(+)CD127(low+/-)CD25(+)-Treg cell pool is critically involved in preterm labor induction and kidney transplant rejection as well. Compared to healthy pregnancies and non-rejecting kidney recipients, we found that the percentage of the FoxP3(+)DR(+)-Treg subset was not reduced, but that the level of HLA-DR expression of such Tregs was strongly diminished in preterm laboring women and in patients with acute renal allograft rejection. In addition, both patient collectives showed a significantly red…

The role of recent thymic emigrant-regulatory T-cell (RTE-Treg) differentiation during pregnancy.

During pregnancy, regulatory T cells (Tregs) have a key role in maternal immune tolerance to the semi-allogeneic fetus. Our previous results showed that the naive CD45RA(+)-Treg pool is functionally improved in pregnant women compared with non-pregnant women. Therefore, we examined the thymic output and differentiation of CD45RA(+)CD31(+) recent thymic emigrant (RTE)-Tregs during normal pregnancy and in the presence of preeclampsia. With the onset of pregnancy, the composition of the total CD4(+)CD127(low+/-)FoxP3(+)-Treg pool changed in the way that its percentage of RTE- and CD45RA(-)CD31(+)-memory Tregs decreased strongly, whereas that of the CD45RA(+)CD31(-)-mature naive (MN)-Tregs did …

Influence of Thymopentin on Antibody Response, and Monocyte and T Cell Function in Hemodialysis Patients Who Fail to Respond to Hepatitis B Vaccination

We investigated the influence of thymopentin as an adjuvant for hepatitis B vaccination on in vitro monocyte and T cell function and in vivo antibody response in a prospective, placebo-controlled double-blind trial in 20 low- and nonresponders to hepatitis B vaccination on chronic hemodialysis. 50 mg thymopentin was given subcutaneously twice per week for 3 weeks, followed by 1 intramuscular injection of 40 micrograms HB-Vax and 3 subsequent injections of thymopentin. After 1 month, the patients were boostered with 40 micrograms HB-Vax. There was no significant difference in T cell and monocyte function after administration of thymopentin, as determined in vitro. After 3 months, 3 patients …

Synthesis, characterization, and hierarchical organization of tungsten oxide nanorods: spreading driven by Marangoni flow.

Tungsten oxide nanorods were synthesized by a soft chemistry approach using tungsten alkoxide and trioctyl amine and oleic acid as the surfactants. The optical properties of the nanorods were studied. The nanorods were found to be soluble in a wide range of solvents like chloroform, cyclohexane, and so on. Upon solvent evaporation, the nanorods formed hierarchically organized solid state structures. Depending on the solvent used, the nanorods organized in different mesostructures. Moreover, the organization of the nanorods from mixtures of polar and nonpolar solvents was studied. Here, the Marangoni effect resulting from differences in the surface tensions of the two solvents was found to p…

Small for gestational age (SGA) neonates show reduced suppressive activity of their regulatory T cells

Little information exists concerning the role of fetal regulatory T cells (Tregs) during intrauterine development. We examined whether complications such as reduced birth weight or the occurrence of preterm labor were associated with deficiencies in the number or in the immunosuppressive activity of Tregs in the fetal circulation. Their total number did not change during normal or complicated pregnancy. In contrast, their level of FoxP3 expression decreased continuously with gestational age and was significantly reduced in the presence of spontaneous term, but not preterm labor. In small for gestational age (SGA) neonates, FoxP3 expression was constantly decreased when compared to age match…

Liquid Crystals from Polymer-Functionalized TiO2 Nanorod Mesogens

In this work, we functionalized TiO2 nanorods with dopamine-functionalized diblock copolymers. After functionalization, they are well dispersible in organic solvents. Light scattering proves that t...

Liquid Crystalline Phases from Polymer-Functionalized TiO2 Nanorods

Solubilisation of multi walled carbon nanotubes by alpha-pyrene functionalised PMMA and their liquid crystalline self-organisation.

alpha-Pyrene functionalised poly(methyl methacrylate) (PMMA) chains were synthesised by RAFT polymerisation and found to be highly efficient to solubilise and disentangle multi walled carbon nanotubes that can now self-organise as liquid crystalline phases in PMMA and PEG 400 matrices.

Clonal analysis of human T lymphocytes infiltrating the liver in chronic active hepatitis B and primary biliary cirrhosis

Human T lymphocytes infiltrating the liver in chronic active hepatitis B (CAH-B) and primary biliary cirrhosis were isolated from liver biopsy cores, cloned by limiting dilution technique and expanded in vitro. Phenotypic and functional analysis demonstrates that this tissue infiltrate represents a heterogeneous cell population. However, when compared to peripheral blood lymphocytes of the same patients, a marked enrichment for T8+ cytotoxic T cells was found to exist at a local site in both types of chronic liver disease. These data provide support for the notion that liver cell injury in CAH-B and PBC may be mediated by a common immunologic mechanism likely executed by cells of the T line…

Definition of discrete signals mediating human T cell activation via differential pathways: Biological and clinical relevance

Distinct subsets of regulatory T cells during pregnancy: is the imbalance of these subsets involved in the pathogenesis of preeclampsia?

Abstract Regulatory T cells (CD4 + CD25 + FoxP3 + -Treg cells) are important regulators of tolerance induction during pregnancy. We now found that the number of CD4 + CD25 + FoxP3 + -Treg cells decreases during normal course of pregnancy and even more so in women affected by preeclampsia. The functional activity of these CD4 + CD25 + -Treg cells was significantly reduced in comparison to those of healthy pregnants. Further analysis revealed two Treg subsets that differed with regard to the FoxP3 and CD25 expression. The percentage of both, CD4 + CD25 + FoxP3 high+ -Treg and CD4 + CD25 high+ FoxP3 + , was maximal in the first and second trimenon, but declined severely in the third trimenon. …

Functional Diblock Copolymers for the Integration of Triboluminescent Materials into Polymer Matrices

This work describes the synthesis and use of new diblock copolymers to integrate functional inorganic particles into a polymer matrix. These diblock copolymers were synthesized by nitroxide-mediated polymerization (NMP) from styrene and two styrene-like monomers with protected functional groups for the later connection to the functional inorganic material. It was possible to keep the polydispersity of the block copolymers around or below 1.2 and to preset the length of the functional block to about 20 monomers or 10 mol-% of monomers. The groups for the surface functionalization (amino groups or chelating ligands) were obtained in their free form by polymer analogous reactions. As an exampl…

Orientation of Polymer Functionalized Nanorods in Thin Films

A directed self assembly of anisotropic nanostructures offers a possibility to provide unique functional materials, which are e.g., important in optoelectronic devices. We use the liquid crystalline behavior of polymer functionalized TiO2 and ZnO nanorods to apply methods well known for low molecular liquid crystals to achieve oriented thin films. Convective forces in the meniscus on a structured substrate obtain thin layers of oriented nanoparticles with a ordering parameter of S = 0.7. As another method we present the orientation of polystyrene covered ZnO nanorods under an applied electric field. The method offers a perpendicular alignment of the rods to the surface.

Suppressive effects of C3b on monocyte-dependent T cell proliferation.

The effect of C3b treatment of human monocytes on secondary antigen-dependent T cell response was studied. When antigen-specific T cell blasts were cultivated together with C3b-treated monocytes the proliferative response was inhibited in a dose-dependent fashion. This suppressive effect was specific for C3b because heat-inactivated C3b or buffer alone had no influence on T cell proliferation. In part, this suppressive effect is mediated through a C3b-induced decreased expression of class II antigens on the surface of treated monocytes, but another suppressive mechanism exists because the C3b pretreatment of monocytes also led to an inhibition of the proliferative response in a class II ant…

Pyrene Containing Polymers for the Non-Covalent Functionalization of Carbon Nanotubes

Pyrene containing diblock copolymers based on poly(methyl methacrylate) were synthesized and investigated regarding their adsorption on carbon nanotubes (CNT). The pyrene units were introduced using a reactive ester monomer for the build up of the second block which later on was reacted polymer-analogously with amine functionalized pyrene derivatives. As we started from the same reactive ester intermediate, full block length identity is given. We varied the length of the anchor block to find an optimal block length and used pyren-1-yl-methylamine as well as 4-pyren-1-yl-butylamine as anchor units. For both anchor units a maximal adsorption was found for 13 and 20 anchor units, respectively.…

Comparative study on biological activities of various anaphylatoxins (C4a, C3a, C5a)

Several anaphylatoxic substances (human C3a, guinea pig C3a, human C4a, guinea pig C5a, and a synthetic C3a-related hexapeptide) were compared with regard to their ability to induce secretion of [3H] serotonin from guinea pig platelets. Functional identity of the C3a preparations, C4a, and the hexapeptide was demonstrated by the phenomenon of crossed desensitization. Whereas C3a of human and guinea pig origin proved to be qualitatively and quantitatively identical, C4a expressed only 3% of the activity of the C3 fragments on a molar basis. Investigations with goat anti-guinea pig C3a demonstrate that human and guinea pig C3a possess one antigenic determinant in common; however, this determi…

Interleukin 1 stimulates T lymphocytes to produce granulocyte-monocyte colony-stimulating factor.

T lymphocytes are thought to cooperatively interact with monocytes to produce colony-stimulating factors (CSF). However, little is known about monocyte-mediated signals leading to CSF-secretion by T lymphocytes, although soluble monocyte products have been implicated. We have employed monoclonal antibody anti-T3B covalently coupled to CnBr-activated Sepharose 4B beads, to show that multimeric ligation of T cell antigen receptor leads to T cell receptiveness to interleukin 1 (IL-1), as indicated by T cell production of CSF, which induces growth of myeloid progenitor cells into neutrophil, eosinophil, and monocyte colonies. To investigate the molecular basis of these findings, total RNA was e…

Chronic T cell leukemia with unusual cellular characteristics in ataxia telangiectasia

Abstract A 27-year-old male patient with ataxia telangiectasia (AT) developed atypical chronic lymphocytic leukemia with increasing bone marrow infiltration in the absence of organomegaly. One-third of the leukemia cells expressed a mature suppressor/cytotoxic T cell phenotype (T3+ T4- T6- T8+ T10-), two-thirds demonstrated additional helper/inducer T cell- associated antigens (T3+ T4+ T6- T8+ T10-), and a small fraction reacted with a natural killer (NK) cell-specific monoclonal antibody (Leu 11+). The proliferative response to stimulation in vitro with lectins and various monoclonal antibodies resembled the proliferation pattern of mature thymocytes: The cells responded to phytohemaggluti…

Uremic serum inhibits monocyte-dependent, but not interleukin-2-dependent steps of T cell proliferation.

We examined the influence of uremic serum on antigen receptor triggered T cell proliferation in dialysis patients with impaired immune function, i.e., 12 nonresponders to hepatitis B vaccination. The dialysis patients showed a monocyte dysfunction and an increased responsiveness to interleukin 2 (IL-2) according to our previous findings. In vitro the addition of IL-2 completely reconstituted the defect. Uremic serum inhibited monocyte-dependent T cell proliferation of patients and of healthy controls. Contrary, monocyte-independent steps of T cell proliferation were not impaired by uremic serum. When IL-2 was added to cultures, the T cell proliferation in the presence of uremic serum was ev…

Immunoelectron microscopic observations on the inflammatory infiltrates and HLA antigens in hepatitis B and non-A, non-B.

The present knowledge of the inflammatory reaction occurring in situ during hepatitis B favors a T cell-dependent MHC-restricted immune response. However, the reports in the literature are primarily based on the application of monoclonal antibodies directed at different lymphocyte subsets which discern only lymphocytic phenotypes and do not reflect the actual situation adequately. Therefore, we investigated the liver biopsies of patients with hepatitis B (28 patients) and non-A, non-B (21 patients) by immunoelectron microscopy with monoclonal antibodies directed at lymphocyte subtypes (pan-B, pan-T, T8, T4 and NKH1) and at activation epitopes (IL-2 receptor, TA1 and T11/3) as well, in order…

Lymphocyte mediated cell lysis.

Lymphocyte-mediated cell lysis represents an important immunologic effector mechanism involved in defense against viral infections, allograft rejection, and tumor surveillance. Moreover, regulatory T cell interactions within the immune system are based, at least in part, on molecular events related to this function. The multiplicity of effector cell populations that can mediate cytotoxicity, the cell/cell interaction determinants which they require for execution of their activities, and molecular events underlying the lytic process itself, as elucidated recently, are the subjects of the present review article.

Comparative study on biological effects of the guinea pig complement-peptide C3a and C3a-related synthetic oligopeptides

Dose-response experiments with guinea pig C3a and a synthetic hexapeptide (amino acid residues 72–77), representing the COOH-terminal sequence of human C3a, were performed in two recently described bioassay systems for C3a, i.e. cytotoxicity against tumor cells measured as LDH and 51Cr-release and non cytolytic serotonin release from guinea pig platelets. Compared to the classical anaphylatoxic assay (guinea pig ileum contraction), nearly identical reactivities were observed in all three test systems with C3a and, although quantitatively different, with hexapeptide.

Platelet Activation: a New Biological Activity of Guinea-pig C3a Anaphylatoxin

3H-serotonin-release from labelled gp-platelets is established as a sensitive method for testing a new biological activity of gp-C3a anaphylatoxin in an autologous situation. Time-, dose- and temperature-dependent release reactions as well as specific inhibition by carboxypeptidase B and anti-C3a antibodies show that C3a is a potent and specific inducer of platelet activation. Inactive C3a does not induce 3H-serotonin-release but specifically inhibits the action of C3a on platelets.

Pathways and Mechanisms of Human T Cell Activation

The antigen receptor of T lymphocytes was recently identified as a complex consisting of a 90 KD disulfide linked heterodimer, termed Ti which is functionally and structurally associated with three additional molecular components, termed T3 (1). Whereas the former contains clonally unique epitopes and displays peptide variability among T cell clones of distinct specificities, no variability could be detected within any of the known three subunits of T3 (2,3). Monoclonal antibodies to T3 and Ti, respectively, in soluble form were capable of blocking antigen specific clonal T cell responses (4,5). Perhaps more importantly, when coupled to the surface of a solid support these antibodies produc…

Liquid crystalline phases from polymer functionalised semiconducting nanorods

The orientation of semiconducting nanomaterials is a hot topic in optoelectronic applications. Liquid crystallinity offers the potential to orient inorganic anisotropic nanorods, if they can be solubilised sufficiently as realised by polymer functionalisation. In this work we functionalised TiO2, SnO2, ZnO and CdTe nanorods with PMMA, PS and PDEGMEMA (poly(diethylene glycol monomethyl ether) methacrylate) diblock copolymers containing anchor groupsvia grafting-to. The block copolymers were synthesised by RAFT polymerisation (PDI ≈ 1.2) via reactive ester diblock copolymers, which were functionalised later with anchor units polymer-analogously. The surface coverage of the nanorods (determine…

Hepatitis B vaccination and interleukin 2 receptor expression in chronic renal failure

Hepatitis B vaccination and interleukin-2 receptor expression in chronic renal failure. Only 50 to 60% of dialysis patients develop anti-HBs antibodies following hepatitis b vaccination. The nonre-sponder state correlates with impaired monocyte function, decreased interleukin-2 (IL-2) production of T cells, and an upregulation of the IL-2 receptor system. In the present study we examined anti-HBs production after hepatitis B vaccination and the in vitro expression of IL-2 receptors in nondialyzed patients with various degrees of chronic renal failure. Forty-four patients with impaired renal function were immunized with 20 µg recombinant hepatitis B vaccine and boostered after one and six mo…

T lymphocyte control of autoreactivity: analysis with human T cell clones and limiting dilution culture

To investigate cellular mechanisms controlling activated autoreactive T lymphocytes, a limiting dilution system was established employing cloned autoreactive major his-tocompatibility complex class II specific lymphocytes (a2/7) as stimulator cells for autologous peripheral blood mononuclear cells. At low responder/stimulator ratios, cytotoxic effector cells were generated capable of lysing clone a2/7. Importantly, within the population of cells mediating autocytotoxic effector function, differential specificities were found to exist. The generation of such autocytotoxic T lymphocytes appears to be inhibited by an additional population of cells circulating at lower frequency suggesting that…

DR(high+)CD45RA(-)-Tregs potentially affect the suppressive activity of the total Treg pool in renal transplant patients.

Recent studies show that regulatory T cells (Tregs) play an essential role in tolerance induction after organ transplantation. In order to examine whether there are differences in the composition of the total CD4(+)CD127(low+/-)FoxP3(+)- Treg cell pool between stable transplant patients and patients with biopsy proven rejection (BPR), we compared the percentages and the functional activity of the different Treg cell subsets (DR(high+)CD45RA(-)-Tregs, DR(low+)CD45RA(-)-Tregs, DR(-)CD45RA(-)-Tregs, DR(-)CD45RA(+)-Tregs). All parameters were determined during the three different periods of time after transplantation (0-30 days, 31-1,000 days, >1,000 days). Among 156 transplant patients, 37 pat…