bluuebunny/crossref_metadata_2025 huggingface dataset:
Human granulocytic ehrlichiosis in pancreas transplant recipients
Authors: Trofe J. , Reddy K.S. , Stratta R.J. , Flax S.D. , Somerville K.T. , Alloway R.R. , Egidi M.F. , Shokouh‐Amiri M.H. , Gaber A.O.
Published: March 2003

Abstract: Human ehrlichioses are tick‐borne infections caused by bacteria in the genus Ehrlichia of the family Rickettsiaceae. To date there have been three cases of ehrlichiosis reported in the transplant population, a human monocytic ehrlichiosis (HME) infection in a liver transplant recipient and two cases of human granulocytic ehrlichiosis (HGE) in kidney transplant recipients. We report three pancreas transplant patients who developed HGE in the last two years at a single southeastern center in the United States. All three patients had clinical, laboratory, and pathophysiologic findings on bone marrow biopsy and peripheral blood smears consistent with HGE, and responded to doxycycline therapy.

In the setting of potent immunosuppression, ehrlichiosis should be considered in the differential diagnosis of transplant patients presenting with persistent fever, pancytopenia, and abnormal liver function. Patients with ehrlichiosis infection may be at risk for developing other opportunistic infections or lymphoproliferative disease.
Immunomodulation of fetal pig islet‐like cell clusters by gamma‐irradiation
Authors: Deol Harjit S. , Tuch Bernard E.
Published: March 2003

Pretreatment of tissues to reduce their immunogenicity is an attractive option, and exposure of donor islets to gamma‐irradiation has previously been shown to result in their prolonged survival when transplanted into rodents. Fetal pig islet‐like cell clusters (ICCs) are currently under trial as a potential xenogeneic tissue for the treatment of type 1 diabetes. The purpose of this study was to examine in vivo and in vitro the immunomodulatory effects of gamma‐irradiation on ICCs in a xenogeneic situation. The immunogenicity of gamma‐irradiated ICCs was determined in a mixed islet lymphocyte culture (MILC), in which fetal pigs ICCs were able to stimulate human peripheral blood mononuclear cells (PBMCs). Exposure of the ICCs to gamma‐irradiation significantly reduced their ability to stimulate PBMCs in a MILC when 10 Gy but not lower doses of irradiation were applied. However, this effect of gamma‐irradiation was variable and was present only in those experiments in which the stimulation index was relatively low. Gamma‐irradiation was toxic to ICCs in vitro, causing a reduction in the [3H]‐thymidine incorporation of 82–94% at 5–20 Gy. This toxic effect of gamma‐irradiation was also demonstrated in vivo: the insulin content of ICCs beneath the renal capsule in SCID mice treated with 5–20 Gy significantly was reduced (P < 0.05) 6 weeks after transplantation. Exposure of ICCs to gamma‐irradiation (2.5 Gy) alone in vitro or in combination with injection of cyclosporine (12.5 mg/kg per day) did not prevent the rejection of ICCs transplanted beneath the renal capsule of BALB/c mice. We conclude that gamma‐irradiation is toxic to fetal pig ICCs at a higher dose and at a lower dose, alone or in combination with cyclosporine, and was unable to prolong discordant islet xenograft survival in mice.
Human–porcine receptor–ligand compatibility within the immune system: relevance for xenotransplantation
Authors: Warrens Anthony N. , Simon Andre R. , Theodore Pierre R. , Sykes Megan
Published: March 2003

Immune responses to xenografts are likely to be highly dependent on the efficiency of molecular interactions between the donor and the recipient species. This brief review summarizes what is currently known about the compatibilities across the human–porcine species barrier of the molecular interactions that are important in the immune response.
Pig xenogeneic antigen modification with green coffee bean α‐galactosidase
Authors: Luo Y. , Wen J. , Luo C. , Cummings R. D. , Cooper D. K. C.
Published: March 2003

Green coffee bean a‐galactosidase can cleave the terminal a‐galactose (αGal) on oligosaccharides that form the major antigen on pig endothelial cells recognized by primate‐specific antibodies. Studies have been made of the conditions under which it is functional (e.g. temperature, pH) and of its biochemical and immunologic effects. Pig‐to‐rhesus monkey vein transplants were studied to identify the efficiency of the enzyme in delaying hyperacute rejection. When a graft became occluded, biopsies were taken for light microscopy (hematoxylin and eosin), scanning electron microscopy (SEM) and immunostaining with Griffonia simplicifolia IB4 lectin (GSIB4), and for IgM, IgG and C3. a‐Galactosidase was stable for 72–96 h and was effective at 4°C and pH 6.9 (conditions of human liver graft storage), although better function was obtained at 20°C and pH 6.5. Using the porcine PK15 cell assay, the cytotoxicity of human serum was reduced after treatment of the pig cells with the enzyme. In vitro studies demonstrated that porcine veins treated with a‐galactosidase lost endothelial expression of the Gal epitope within 30 min. SEM, however, demonstrated endothelial damage beginning within 2 h, probably caused by the a‐galactosidase, as no damage was found in phosphate‐buffered saline‐treated veins, where the Gal epitope was preserved for > 3 h. No change was found in either group on light microscopy. In vivo studies demonstrated that patency of the a‐galactosidase‐treated veins (mean 2.5 h) was longer than that of untreated veins (0.23 h) (P < 0.01). Biopsies showed no GSIB4 lectin staining for a‐Gal epitopes and much less IgM and C3 deposition in the treated group. Light microscopy and SEM demonstrated more severe endothelial damage, hemorrhage, and fibrin formation in the untreated group. Galactosidase is effective in removing the terminal αGal and delays the onset of hyperacute rejection of pig veins transplanted into monkeys. However, its effect is temporary and, on its own, its use is unlikely to prolong survival of pig organs transplanted into primates sufficiently to be of clinical value.
Development and analysis of transgenic mice expressing porcine hematopoietic cytokines: a model for achieving durable porcine hematopoietic chimerism across an extensive xenogeneic barrier
Authors: Yang Yong‐guang , Chen Ann M. , Garrett Lisa J. , Sergio Justin J. , Theodore Pierre , Awwad Michel , VerHalen Jon , Bodine David M. , Sachs David H. , Sykes Megan
Published: March 2003

Abstract: The capacity of mixed hematopoietic chimerism to induce tolerance has not been demonstrated in discordant xenogeneic species combinations because of the difficulty in achieving lasting hematopoietic engraftment. In an effort to create a model of long‐lasting disparate xenogeneic hematopoietic chimerism, we have developed transgenic (Tg) mice carrying porcine cytokines. Three lines of Tg mice were generated: one carrying porcine IL‐3 and GM‐CSF genes only (termed IL/GM) and the remaining two lines carrying in addition, the soluble SCF gene (termed IL/GM/sS) or membrane‐bound SCF gene (termed IL/GM/mS). Sera from mice with IL/GM and IL/GM/sS transgenes markedly stimulated the proliferation of swine marrow cells in vitro. However, proliferation of swine marrow cells was not induced in cultures containing IL/GM/mS sera. Consistent with these observations, ELISA assays revealed detectable levels of porcine cytokines in the sera of IL/GM and IL/GM/sS, but not in sera of IL/GM/mS Tg mice. Marrow stromal cells prepared from all three kinds of Tg mice, but not those from non‐Tg littermates, were capable of supporting the growth of porcine hematopoietic cells in vitro. Immunodeficient Tg mice were generated by crossing Tg founders with C.B‐17 SCID mice for five generations. All Tg immunodeficient mice showed improved porcine hematopoietic engraftment compared with non‐Tg controls. These Tg mice provide a useful model system for studying porcine hematopoietic stem cells, and for evaluating the feasibility of donor‐specific tolerance induction by mixed chimerism across highly disparate xenogeneic barriers.
Different mechanisms mediate the rejection of porcine neurons and endothelial cells transplanted into the rat brain
Authors: Rémy Séverine , Canova Cécile , Daguin‐Nerrière Véronique , Martin Caroline , Melchior Benoît , Neveu Isabelle , Charreau Béatrice , Soulillou Jean‐Paul , Brachet Philippe
Published: March 2003

Abstract: In order to investigate the early cellular responses mediating xenograft rejection in the brain, porcine aortic endothelial cells (PAEC) or porcine fetal mesencephalic neurons (PNEU) were transplanted into the striatum of LEW.1A rats. PAEC were detected with a specific anti‐β1 integrin antibody, and PNEU with an anti‐porcine neurofilament antibody, or an antibody recognizing the NeuN antigen. PAEC grafts were massively infiltrated within 24 h by OX42‐positive cells, which may correspond to polymorphonuclear (PMN) cells or macrophages. At that moment, the graft contained numerous cells expressing the inducible isoform of NO‐synthase (iNOS). Infiltration by ED1‐positive macrophages was effective after three days. The β1‐integrin labeling decreased from that time‐point to day 7 post‐implantation, and vanished after 11 days. Although some OX8‐positive cells were present around the graft as soon as 3 days after transplantation, cells expressing the T‐cell receptor (TCR)‐β chain infiltrated the graft after 7 days and their number remained low. A strong, diffuse OX8‐and ED1‐positive immunoreactive material remained in the scar up to the third week. In striking contrast, PNEU grafts remained poorly infiltrated by OX42‐ or ED1‐positive cells during the first two weeks. A massive infiltration by macrophages and TCRβ‐positive lymphocytes occurred after 3 weeks. Natural killer (NK) cells were more scarce. The inflammation territory enlarged, and blood vessels were overloaded with macrophages or lymphocytes. Nevertheless, the graft contained NeuN‐positive nuclei and neurites harbouring the porcine neurofilament protein. Hence, rejection was not completed at this time‐point. These results suggest that the rapid rejection of PAEC is mainly driven by macrophages and possibly PMN cells, unlike PNEU, whose rejection is delayed and also involves lymphocytes. Differences in immunogenicity of grafted cells and/or patterns of production of pro‐inflammatory cytokines may account for these contrasted rejection kinetics.
Hamster cardiac xenografts are protected against antibody mediated damage, early after transplantation to Lewis rats
Authors: Vriens Patrick W. , Pollard Jeffrey D. , Hoyt Grant , Morris Randall E. , Scheringa Marcel , Bouwman Eelco , Robbins Robert C.
Published: March 2003

Abstract: Antibodies play a crucial role in the rejection of xenografts. We tested the hypothesis that xenografts are protected against antibody‐mediated attack early after transplantation in a concordant model. We investigated the role of xenoreactive antibodies as a stimulus for protection and the effects of a total blockade of the antibody response by the leflunomide analog malononitrilamide 279. Hamster cardiac xenografts were transplanted to Lewis rat recipients. Second transplants and retransplants of xenografts were performed to untreated rats that had a xenograft in place for 3 d. Untreated rats rejected hamster cardiac xenografts after 4.0 ± 0.0 d. Significant levels of anti‐donor IgM, as measured by flowcytometry, were present on day 3 after transplantation (11.2% ± 2.8 vs. 1.2% ± 0.0 on day 0, P < 0.001). ‘Fresh’ second xenografts transplanted to rats that had a first xenograft in place for 3 d and had anti‐hamster antibodies, underwent hyperacute rejection. The first xenografts remained functioning. Xenografts that were removed on day 3 from untreated rats and then retransplanted remained functioning. Xenografts that were removed on d 3 from rats that had been treated with malononitrilamide 279, 15 mg/kg/d and were retransplanted underwent hyperacute rejection. IgM levels at the time of removal were 1.1% ± 0.5 in these rats and not different from baseline (P = 0.96). We conclude that xenografts are protected against antibody‐mediated damage early after transplantation. The presence of anti‐donor antibodies might be an essential stimulus for the induction of protection. There seems to be a delicate balance between the injurious and protective effects of antibodies. Treatment strategies that are designed to block antibody formation completely might prevent the induction of protection.
Production and characterization of a pig line transgenic for human membrane cofactor protein
Authors: Zhou Chun‐Yan , McInnes Elizabeth , Parsons Nicola , Langford Gillian , Lancaster Richard , Richards Andrew , Pino‐Chavez Gilda , Santos Cruz Gabriela Dos , Copeman Laura , Carrington Christine , Thompson Simon
Published: March 2003

A pig line transgenic for human membrane cofactor protein (hMCP) has been established. Offspring from the founder were produced by crossing the founder with pigs heterozygous for the human decay accelerating factor (hDAF) transgene. As a result, pigs transgenic for both hMCP and hDAF have been produced. Ribonuclease protection assay (RPA) indicated that hMCP was expressed in all the tissues analysed. In addition, immunohistochemical results indicated a high level of expression of hMCP on neural tissues and islets where hDAF was absent or weakly expressed. C3 fragment deposition and cytotoxicity assays indicated that hMCP expression alone on pig endothelial cells and peripheral blood lymphocytes (PBLs) provided protection against human complement mediated damage. However, we did not find that porcine endothelial cells expressing both hDAF and hMCP were better protected than those expressing hDAF alone. The expression of hMCP on tissues where hDAF is not expressed could provide these tissues with protection against human complement mediated lysis.
Upper molar distalization: a critical analysis
Authors: Sfondrini MF , Cacciafesta V , Sfondrini G
Published: March 2003

Traditional upper molar distalization techniques require patient co‐operation with the headgear or elastics. Recently, several different intraoral procedures have been introduced to minimize the need for patient co‐operation. This article reviews the appliances currently available for maxillary molar distalization and critically analyses their dentoalveolar and skeletal effects.
Analysis of facial growth in subjects with syndromic ectodermal dysplasia: a longitudinal analysis
Authors: Bondarets N , Jones RM , McDonald F
Published: March 2003

Structured Abstract

Authors– Bondarets N, Jones RM, McDonald F.

Objective– To examine the craniofacial growth pattern of patients diagnosed with syndromic ectodermal dysplasia.

>Design– Mixed longitudinal analysis of lateral cephalograms.

Setting– The data were analysed using a multilevel modelling technique with the MLwiN application software and the results presented numerically and graphically.

Sample Population– All 61 subjects had severe hypodontia with the number of absent teeth (excluding third molars) ranging from 6 to 28 (mean=15.4). At presentation the subjects had a mean age of 133 months and were followed longitudinally for between one and five subsequent occasions (mean 2.66 occasions; mean age at completion of observation 207 months).

Outcome Measures– Lateral cephalograms taken at each visit.

Experimental Variables– Analysis of four angular measurements and four linear measurements, together with one calculated ratio.

Results– Growth curves are presented showing the trends of craniofacial growth.

Conclusions– The most significant findings were for a universal tendency for the individuals to undergo a change in sagittal relationship of the jaws, becoming markedly more Class III with time. We have also demonstrated a significant difference in growth between the anterior and posterior face heights indicating that the subjects have a tendency to an anterior growth rotation.
Upper removable appliance or Jones Jig for distalizing first molars? A randomized clinical trial
Authors: Paul LD , O'Brien KD , Mandall NA
Published: March 2003

Aim –
To compare the effectiveness of two intra‐oral methods of distalizing upper first permanent molars: an upper removable appliance (URA) and a Jones Jig.

Sample –
Twelve patients were randomly allocated to URA treatment and 11 patients to a Jones Jig.

Methods –
Upper study models were collected at the start of treatment and after 6 months of appliance wear. The amount of distal movement, tipping and rotation of the upper first permanent molars and mesial movement of the upper first permanent premolars was measured using a reflex metrograph.

Results – There were no statistically significant differences between the two treatment methods for any of the outcome measures (P < 0.05). Distal movement obtained by both appliances was approximately 1 mm.

Conclusions –
The amount of distal movement obtained with both appliances was small and no differences were shown in the amount of molar tooth movement. It is suggested that there is no advantage in using the Jones Jig as a non‐compliance appliance.
Melatonin disrupts circadian rhythms of glutamate and GABA in the neostriatum of the awake rat: a microdialysis study
Authors: Marquez de Prado B. , Castañeda T.R. , Galindo A. , Del Arco A. , Segovia G. , Reiter R.J. , Mora F.
Published: March 2003

The purpose of this study was to investigate possible circadian changes in extracellular concentrations of glutamate (GLU) and γ‐aminobutyric acid (GABA), and the influence of melatonin on the levels of these neurotransmitters in the neostriatum of awake rats using in vivo microdialysis. At the same time, the concentrations of the amino acids taurine (TAU), glutamine (GLN) and arginine (ARG), as well as dopamine (DA) and its metabolites 3, 4‐dihydroxyphenyl acetic acid (DOPAC) and homovanillic acid (HVA), were measured in the extracellular fluid. When dialysates were collected over a 24‐hr period (6 hr dark, 12 hr light, 6 hr dark), both GLU and GABA, without the infusion of melatonin, exhibited statistically significant rhythms, with higher levels of these constituents during the dark and lower levels during the day. Perfusion with melatonin (for 19 consecutive hours) prevented the daytime reductions in both GLU and GABA. Of the amino acids measured in the dialysates collected from the neostriatum of non‐perfused rats, only ARG exhibited a significant change during the light:dark cycle; again, lowest concentrations were measured during the day. While melatonin perfusion did not statistically significantly influence neostriatal levels of TAU and ARG, GLN levels continued to drop during the infusion of the indoleamine. Dialysate concentrations of DA, DOPAC and HVA exhibited circadian rhythms which were not influenced by melatonin perfusion. The findings indicate there are differential effects of melatonin on extracellular neurotransmitter concentrations in the neostriatum of the awake rat. The results also suggest that the day:night variations in GLU and GABA may relate to daily changes in endogenous melatonin production, while DA and its metabolites are minimally influenced by this secretory product.
Physiologic functions of activating natural killer (NK) complex‐encoded receptors on NK cells
Authors: Ryan James C. , Naper Christian , Hayashi Shigenari , Daws Michael R.
Published: March 2003

Summary: Natural killer (NK) cells express a superfamily of surface proteins that share common structural features: dimeric type II integral membrane proteins with extracellular domains resembling C‐type lectins. These receptors are encoded by a single genetic region called the NK complex (NKC). The NKC encompasses several families of genes including NKR‐P1, Ly‐49, CD94/NKG2, and NKG2D. Different NKC‐encoded receptors have been shown to activate or to inhibit NK‐cell function, and different receptors within the same family can have opposing functions. Within an individual NK cell, inhibitory receptors typically predominate over stimulatory receptors, calling into question the teleologic requirement or physiologic significance of lectin‐like activating receptors in NK cells. Despite the widespread expression of inhibitory receptors, however, subtle features of activating receptor biology enable them to stimulate effector functions in vivo and in vitro. Activating receptors and inhibitory receptors differ in their subset expression, in their structural constraints for binding to common ligands, in their ligand repertoires, and in that divergent families of activating receptors utilize different signaling pathways. These subset, binding, repertoire, and signaling diversities may allow activating receptors to manifest their effects in spite of inhibitory receptor functions during pathologic conditions in vivo. In this review, we will present a detailed analysis of the data supporting this hypothesis with particular relevance toward physiologic NK‐cell functions.

This work was supported by the United States Veterans Administration, by grants from the National Institutes of Health RO1 AI44126 (J.C.R) and from the Norwegian Cancer Society (C.N).
Biology of T memory type 1 cells
Authors: Anfossi Nicolas , Pascal Véronique , Vivier Eric , Ugolini Sophie
Published: March 2003

Summary: Engagement of inhibitory natural killer (NK) cell receptors for MHC class I molecules (NKR) can impair NK‐cell activation programs. Inhibitory NKR thus confer to NK cells the capacity to discriminate between MHC class I+ and MHC class I− target cells, and are therefore involved in the control of NK‐cell tolerance to self, as well as in the elimination of MHC class I− distressed cells by NK cells. In human and mouse, a subset of αβ T cells also express inhibitory NKR at their surface, but the biological function of inhibitory NKR on T cells remains to be precisely elucidated. We refer to these cells as T memory type 1 (Tm1) cells, and review here the phenotypic and functional features of this subset of memory‐phenotype CD8+αβ T cells. In vitro studies suggest that inhibitory NKR are involved in the peripheral control of T‐cell self‐tolerance. In vitro and in vivo analysis have revealed a novel biological function for inhibitory NKR when expressed on T cells. Indeed, engagement of inhibitory NKR on T cells provides them with survival signals against activation‐induced cell death. Thus, sensing of self‐MHC class I molecules by inhibitory NKR displayed on αβ T cells leads to the in vivo accumulation of Tm1 cells.

The authors thank C. Arpin, J. Marvel (INSERM 503, CERVI, Lyon), C. Melief, R. Toes (Leiden University Medical Center, The Netherlands), D. Raulet (Berkeley, USA) and N. Glaichenhaus (IPMC, Nice) for helpful discussions and help, as well as F. Romagné (Immunotech) for the generous gift of MHC class I tetramers. This work was supported by institutional grants from INSERM, CNRS, Ministère de l’Enseignement Supérieur et de la Recherche, and specific grants from Ligue Nationale contre le Cancer (E. V., Equipe labellisée La Ligue; S. U.), from Association pour la Recherche contre le Cancer (E.V.), and from SIDACTION (S.U.).
Notch signalling in the regulation of peripheral immunity
Authors: Hoyne Gerard F. , Dallman Margaret J. , Champion Brian R. , Lamb Jonathan R.
Published: March 2003

Summary: Notch signalling plays a critical role in embryogenesis, influencing the differentiation and growth of a variety of cell types across the species. In the mammalian immune system, Notch signalling operates at various levels; it controls the differentiation of haematopoietic stem cells and directs the early development of the T and B‐cell lineages. It is also involved in the maturation of both CD4+ and CD8+ T cells in the thymus. The biological activities of this pathway extend beyond lymphocyte ontogeny; recent evidence has shown that it also contributes to the regulation of the peripheral immune system through its ability to influence cell survival and growth. In fulfilling this function, Notch signalling appears to act in conjunction with defined immunological signals such as cytokines, T‐cell antigen receptor and co‐stimulatory receptor‐mediated signalling. In this review we discuss the potential of the Notch signalling pathway in the maintenance of homeostasis within the immune system affecting both peripheral tolerance and the negative feedback controlling productive immunity. The therapeutic manipulation of this pathway is likely to have broad application in a range of immunologically based diseases.
Mast cell modulation of immune responses to bacteria
Authors: Malaviya Ravi , Abraham Soman N.
Published: March 2003

Summary: Mast cells are key elements of the immune system. These cells release a wide variety of pro‐inflammatory mediators which are responsible for the pathophysiology of many allergic diseases. Recent studies, however, have shown that mast cells have the capacity to modulate the host's innate immune response to gram negative bacteria by their ability to phagocytose bacteria, process and present bacterial antigens to T cells and recruit phagocytic help through the release of physiological amounts of pro‐inflammatory mediators. Here, current knowledge of mast cell responses to gram negative bacteria and molecular mechanisms associated with mast cell bacteria interaction is reviewed.

This work was supported in part by NIH research grant AI45013. We are grateful to Ms. Tamara Paul for critical review of the manuscript.
Regulation of human intestinal mast cells by stem cell factor and IL‐4
Authors: Lorentz Axel , Bischoff Stephan C.
Published: March 2003

Summary: Mature human mast cells are tissue‐residing, key effector cells of immediate allergic reactions. Moreover, mast cells have been recognized as a potent cellular source of multiple cytokines, suggesting an important role in immunoregulation and host defense. Here, we report on the regulation of mature human mast cells isolated from intestinal tissues by stem cell factor (SCF) and interleukin (IL)‐4. SCF is substantially necessary for mast cell survival and induces marginal mast cell proliferation in vitro, whereas IL‐4 by itself has no effects on mast cell survival or proliferation. Most interestingly, in synergy with SCF, IL‐4 strongly enhances mast cell proliferation. In the presence of SCF, mast cells predominantly produce pro‐inflammatory cytokines including tumor necrosis factor (TNF)‐α, IL‐1β, IL‐6, IL‐8, IL‐16, and IL‐18. Addition of IL‐4 to the culture medium induces the expression of Th2‐type cytokines (IL‐3, IL‐5 and IL‐13), and a downregulation of pro‐inflammatory cytokines, namely IL‐6. Furthermore, SCF by itself supports the predominance of the tryptase/chymase double‐positive mast cell subtype MCTC, whereas the addition of IL‐4 supports the chymase negative MCT subtype. In conclusion, SCF may primarily regulate resident mast cell survival, whereas IL‐4 may promote local proliferation of mast cells and their expression of Th2‐type cytokines.

This research was supported by the Deutsche Forschungsgesellschaft (SFB280‐C8).
DNA‐based immunotherapeutics for the treatment of allergic disease
Authors: Horner Anthony A. , Van Uden John H. , Zubeldia Jose M. , Broide David , Raz Eyal
Published: March 2003

Summary: Allergic diseases are a growing health concern in industrialized countries. Despite a number of effective therapeutic options for the prevention and treatment of the pathophysiologic responses which characterize allergic diseases, the induction of true allergen desensitization remains an elusive therapeutic goal. Only immunotherapy (IT) has been shown to have any effect on the underlying hypersensitivities which mediate allergic reactions, and traditional protein‐based allergen IT has a limited scope of efficacy. However, a number of reagents collectively termed DNA‐based immunotherapeutics have proven highly effective in both the prevention and reversal of Th2‐mediated hypersensitivity states in mouse models of allergic disease. Four basic DNA‐based immunotherapeutic modalities have been used for these studies. These include immunization with gene vaccines, allergen mixed with immunostimulatory oligodeoxynucleotide (ISS‐ODN), and physical allergen–ISS‐ODN conjugates (AIC), as well as immunomodulation with ISS‐ODN alone. Results from many laboratories have generated guarded optimism that DNA‐based immunotherapeutics may be effective for the reversal of allergic hypersensitivity states in humans, and several clinical trials have already been initiated. This review will focus on our present understanding of the biological activities of DNA‐based immunotherapeutics and their application to the treatment of allergic diseases.

This work was supported by grants AI40682 and AI01490 from the NIH and by a grant from Dynavax Technologies Corporation. J.H.V. is also a Medical Scientist Training Program Trainee.
Instructive selection and immunological theory
Authors: Lederberg Joshua
Published: March 2003

Summary: The turning point of modern immunological theory was the advent of the clonal selection theory (Burnet, Talmage − 1957). A useful heuristic in the classification of theoretical models was the contrast of ‘instructive’ with ‘selective’ models of the acquisition of information by biological systems. The neo‐Darwinian synthesis of the 1940s had consolidated biologists' model of evolution based on prior random variation and natural selection, viz. differential fecundity. While evolution in the large was by then pretty well settled, controversy remained about examples of cellular adaptation to chemical challenges, like induced drug‐resistance, enzyme formation and the antibody response. While instructive theories have been on the decline, some clear cut examples can be found of molecular imprinting in the abiotic world, leading, e.g. to the production of specific sorbents. Template‐driven assembly, as in DNA synthesis, has remained a paradigm of instructive specification. Nevertheless, the classification may break down with more microscopic scrutiny of the processes of molecular fit of substrates with enzymes, of monomers to an elongating polymer chain, as the reactants often traverse a state space from with activated components are appropriately selected. The same process may be ‘instructive’ from a holistic, ‘selective’ from an atomic perspective.
The role of endothelial cell lateral junctions during leukocyte trafficking
Authors: Luscinskas Francis W. , Ma Shuo , Nusrat Asma , Parkos Charles A. , Shaw Sunil K.
Published: March 2003

Summary: An essential function of the inflammatory response is selective targeting of appropriate leukocyte types to a site of infection or injury. The past decade has witnessed an explosion in the level of detail concerning the identification and deciphering of the molecular mechanisms that capture leukocytes from flowing blood and promote leukocyte arrest on the vessel wall. In contrast, less information is known about the migration of adherent blood leukocytes through endothelial cell‐to‐cell borders (transendothelial migration, TEM) and into the underlying tissues. This article reviews the endothelial‐dependent mechanisms that coordinate TEM in peripheral vasculature and highlights the role of certain lateral junctional proteins and protein complexes.
The regulation of actin remodeling during T‐cell–APC conjugate formation
Authors: Cannon Judy L. , Burkhardt Janis K.
Published: March 2003

Summary: The T‐cell cytoskeleton is intimately involved in determining the efficiency and fidelity of the immune response. During T‐cell interactions with antigen‐presenting cells (APCs), dynamic remodeling of the actin cytoskeleton is particularly important for stabilizing long‐lived integrin‐dependent adhesive interactions. In addition, actin remodeling is important for facilitating the sustained signaling required for full T‐cell activation. Although the relationship between T‐cell signaling and cytoskeletal remodeling is complex, new molecular genetic tools are making it possible to investigate individual molecular interactions in the context of bona fide conjugate formation. We describe here the progress from our laboratory toward defining the pathways required for actin remodeling during conjugate formation. Our studies show that engagement of T‐cell receptor (TCR) and leukocyte functional antigen‐1 (LFA‐1) leads to distinct effects on the remodeling of individual cytoskeletal elements. Downstream of TCR, we find that p56Lck (Lck) plays a critical role in integrin‐dependent adhesion independent of its ability to activate zeta‐associated protein of 70 kDa (ZAP‐70). TCR engagement also results in the assembly of a signaling complex that facilitates the activation of Wiskott–Aldrich syndrome protein (WASP) by colocalization with Cdc42‐GTP. These events, together with other parallel actin regulatory pathways, induce localized actin polymerization at the site of APC binding.
Genetic analysis of integrin activation in T lymphocytes
Authors: Kellermann Sirid‐Aimée , Dell Cheryl L. , Hunt Stephen W. , Shimizu Yoji
Published: March 2003

Summary: Among the myriad receptors expressed by T cells, the sine qua non is the CD3/T cell receptor (CD3/TCR) complex, because it is uniquely capable of translating the presence of a specific antigen into intracellular signals necessary to trigger an immune response against a pathogen or tumor. Much work over the past 2 decades has attempted to define the signaling pathways leading from the CD3/TCR complex that culminate ultimately in the functions necessary for effective T cell immune responses, such as cytokine production. Here, we summarize recent advances in our understanding of the mechanisms by which the CD3/TCR complex controls integrin‐mediated T cell adhesion, and discuss new information that suggests that there may be unexpected facets to this pathway that distinguish it from those previously defined.
Sequence variation in the human T‐cell receptor loci
Authors: Mackelprang Rachel , Carlson Christopher S. , Subrahmanyan Lakshman , Livingston Robert J. , Eberle Michael A. , Nickerson Deborah A.
Published: March 2003

Summary: Identifying common sequence variations known as single nucleotide polymorphisms (SNPs) in human populations is one of the current objectives of the human genome project. Nearly 3 million SNPs have been identified. Analysis of the relative allele frequency of these markers in human populations and the genetic associations between these markers, known as linkage disequilibrium, is now underway to generate a high‐density genetic map. Because of the central role T cells play in immune reactivity, the T‐cell receptor (TCR) loci have long been considered important candidates for common disease susceptibility within the immune system (e.g., asthma, atopy and autoimmunity). Over the past two decades, hundreds of SNPs in the TCR loci have been identified. Most studies have focused on defining SNPs in the variable gene segments which are involved in antigenic recognition. On average, the coding sequence of each TCR variable gene segment contains two SNPs, with many more found in the 5′, 3′ and intronic sequences of these segments. Therefore, a potentially large repertoire of functional variants exists in these loci. Association between SNPs (linkage disequilibrium) extends approximately 30 kb in the TCR loci, although a few larger regions of disequilibrium have been identified. Therefore, the SNPs found in one variable gene segment may or may not be associated with SNPs in other surrounding variable gene segments. This suggests that meaningful association studies in the TCR loci will require the analysis and typing of large marker sets to fully evaluate the role of TCR loci in common disease susceptibility in human populations.
Transmembrane adapters: attractants for cytoplasmic effectors
Authors: Lindquist Jonathan A. , Simeoni Luca , Schraven Burkhart
Published: March 2003

Transmembrane adapter proteins (TRAPs) are a relatively new and growing family of proteins that include linker for activation of T cells (LAT), phosphoprotein associated with glycosphingolipid‐enriched micro domains (PAG)/C‐terminal Src kinase (Csk) binding protein (Cbp), SHP2‐interacting transmembrane adapter protein (SIT), T cell receptor interacting molecule (TRIM), and the recently identified non‐T cell activation linker (NTAL) and pp30. TRAPs share several common structural features, but more importantly they possess multiple sites of tyrosine phosphorylation, by which they act as scaffolds for recruiting cytosolic adapter and/or effector proteins. The membrane association of TRAPs places them near to the immunoreceptors, a position from which they coordinate and modulate the signals they receive to produce an appropriate cellular response.
Liver transplantation for primary sclerosing cholangitis
Authors: Gow Paul J. , Chapman Roger W.
Published: March 2003

Abstract: Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown aetiology that is progressive in most symptomatic patients, advancing toward cirrhosis and liver failure. Liver transplantation is the only therapeutic option for patients with end stage liver disease resulting from this disorder. The results of transplantation for PSC are excellent with one‐year survival rates of 90–97% and five‐year survival rates of 80–85%, but are closely related to pre‐transplant Child‐Pugh stage. Recurrence of PSC after liver transplantation is common, occurring in up to 20% of patients, but it appears to have little effect on patient survival, as survival of patients with recurrent PSC is similar to that of those without evidence of recurrence. Cholangiocarcinoma is a catastrophic complication of PSC and as yet no reliable screening method exists. The results of liver transplantation for patients with clinically apparent cholangiocarcinoma are extremely poor, however in patients in whom a microscopic tumour is detected in the explanted liver, survival is similar to those transplanted with PSC without cholangiocarcinoma. Activity of inflammatory bowel disease (IBD) appears to be more severe after transplantation, especially in units where steroid immunosuppression is withdrawn early. Colon cancer appears within the first few years after transplantation in approximately 7% of patients with IBD who are transplanted for PSC. Annual colonoscopy in this population seems prudent.
Role of serum soluble Fas/soluble Fas ligand and TNF‐α on response to interferon‐α therapy in chronic hepatitis C
Authors: Toyoda Mitsuo , Kakizaki Satoru , Horiguchi Norio , Sato Ken , Takayama Hisashi , Takagi Hitoshi , Nagamine Takeaki , Mori Masatomo
Published: March 2003

Abstract: Aims/Background: To determine the relationship between host factors and host response to interferon (IFN) therapy, serum soluble Fas (sFas), soluble Fas ligand (sFas ligand), and tumor necrosis factor‐α (TNF‐α) were analyzed in 41 patients with chronic hepatitis C (CH‐C) treated with IFN‐α. Methods: Serum levels of sFas, sFas ligand, and TNF‐α were measured at 0, 4, and 24 weeks of IFN therapy. Results: Eighteen patients were complete responders (CR) and 23 patients were non‐responders (NR). Serum levels of sFas and TNF‐α in patients with CH‐C were significantly higher than those in healthy controls (p<0.01 and p<0.01, respectively). Serum sFas ligand levels were significantly lower in CH‐C patients than in healthy controls (p<0.01). Before IFN therapy, serum levels of sFas in NR were significantly higher than those in CR (p<0.05). At 4 weeks of IFN therapy, serum levels of sFas of CR were significantly elevated compared with levels before IFN therapy (p<0.05). Serum levels of sFas correlated with the histological activity of the liver (p<0.05) and alanine aminotransferase (p<0.05). None of the three parameters, serum sFas, sFas ligand, or TNF‐α levels, correlated with each other, with HCV‐RNA genotype or with serum HCV‐RNA load. Multiple logistic regression analysis showed that serum sFas levels before IFN therapy were a contributive factor to predict efficacy of IFN therapy. Conclusions: Serum sFas/sFas ligand and TNF‐α play a possible role in pathogenesis of CH‐C and also in IFN therapy. Serum sFas levels before IFN therapy may be one of the host‐related factors used for evaluating the response of CH‐C patients to IFN therapy.
Experimental autoimmune cholangitis: a mouse model of immune‐mediated cholangiopathy
Authors: Jones David E. J. , Palmer Jeremy M. , Kirby John A. , De Cruz Dawn J. , McCaughan Geoffrey W. , Sedgwick Jonathon D. , Yeaman Stephen J. , Burt Alastair D. , Bassendine Margaret F.
Published: March 2003

Abstract: Background: Primary biliary cirrhosis (PBC) is characterised by intra‐hepatic immune‐mediated cholangiopathy (non‐suppurative destructive cholangitis (NSDC)). Although auto‐reactive immune responses against pyruvate dehydrogenase complex (PDC) have been characterised in PBC, the lack of an animal model of the disease has limited study of the mechanisms of disease induction and the development of novel approaches to therapy. Aims: To develop and validate a mouse model of immune‐mediated cholangiopathy relevant for future use in the study of the aetio‐pathogenesis and therapy of PBC. Methods: Female SJL/J, C57BL/6, NOD and BALB/c mice were sensitised with PDC, its purified E2/E3BP component, and a PDC‐E2 derived peptide p163 (a dominant T‐cell epitope in humans) in complete Freund's adjuvant (CFA). Morphological changes were assessed under light microscopy by a hepatic histopathologist blinded to the experimental details. Antibody responses to PDC were studied by ELISA and PDC inhibition assay. Results: An initial series of experiments was performed to survey the susceptibility of female mice of a range of strains to the induction of NSDC by i.p. sensitisation with PDC, PDC‐E2/E3BP or p163 in CFA. Although each animal showed a specific antibody response following sensitisation, it was found that NSDC development (assessed at 30 weeks post‐sensitisation) was restricted to SJL/J mice following sensitisation with any of the mitochondrial antigen preparations. A subsequent series of experiments was performed to examine the specificity and aetiology of this disease. Significant bile duct lesions were only seen in SJL/J animals following sensitisation with CFA containing PDC, and were absent from CFA only and un‐sensitised controls. Kinetic analysis revealed that this pathology developed slowly, but a high incidence of animals with severe lesions was observed after 30 weeks. Conclusions: We have described a model of experimental autoimmune cholangitis (EAC) with immunological (anti‐PDC antibodies) and histological (immune‐mediated cholangiopathy) features suggestive of PBC. This model may be useful in further defining the role of self‐tolerance breakdown in the development of this condition.
Expression of isoforms and splice variants of the latent transforming growth factor β binding protein (LTBP) in cultured human liver myofibroblasts
Authors: Mangasser‐Stephan Kerstin , Gartung Carsten , Lahme Birgit , Gressner Axel M.
Published: March 2003

Abstract: Background/Aims: The activation of hepatic stellate cells (HSC) to extracellular matrix (ECM) producing myofibroblasts (MFB) is the key pathogenetic event in human liver fibrogenesis. Latent transforming growth factor β binding protein (LTBP), a component of the profibrogenic large latent transforming growth factor (TGF)‐β complex, is suggested to be important for secretion, latency, storage and activation of TGF‐β in the ECM. This study was performed to identify the expression profile of all hitherto known LTBP isoforms and LTBP splice variants in conjunction with that of TGF‐β isoforms in cultured human liver MFB. Methods: Cultured human MFB were analyzed for TGF‐β and LTBP using reverse‐transcription polymerase chain reaction (RT‐PCR), sequence analysis, immunofluorescence staining, metabolic labeling, immunoprecipitation, and enzyme‐linked immunosorbent assay (ELISA). Results: Transcripts of all three TGF‐β isoforms, of all four LTBP isoforms and of nearly all splice variants of LTBP‐1 and LTBP‐4 so far known were detected. Metabolic labeling followed by immunoprecipitation with anti‐LTBP‐1 antibody revealed the synthesis of LTBP proteins. Secretion of free LTBP and LTBP integrated into the large latent TGF‐β complex was demonstrated by size‐exclusion chromatography. Co‐localization of LTBP‐1 and ‐2 with fibronectin and collagen type I was observed by double immunofluorescence staining. Conclusion: The expression of a complete profile of hitherto known LTBP proteins by cultured human MFB suggests a role in modulating the bioactivity of TGF‐β in the diseased liver.
Circulating levels of insulin‐like growth factors and their binding proteins in patients with chronic liver disease: lack of correlation with bone mineral density
Authors: Ormarsdóttir Sif , Ljunggren Östen , Mallmin Hans , Olofsson Helena , Blum Werner F. , Lööf Lars
Published: March 2003

Abstract: Background/Aims: Insulin‐like growth factor‐I (IGF‐I) levels are low in patients with chronic liver disease (CLD) and have been found to correlate with measurements of bone mineral density (BMD) in men with viral cirrhosis. The aim of this study was to investigate the relationship between circulating IGF‐I levels and BMD in patients with CLD of other causes. Methods: Fifty‐eight patients with CLD were included. Age‐ and sex‐matched normal individuals served as controls. Serum levels of IGF‐I and IGF‐II and their binding proteins (IGFBP‐1–3) were measured by radioimmunoassay. BMD was measured by dual energy X‐ray absorptiometry. Results: IGF‐I levels were 57±33 and 136±48 ng/ml; p<0.0001 in patients and controls, respectively. IGF‐II and IGFBP‐3 levels were lower (p<0.0001) and IGFBP‐1 and IGFBP‐2 levels were higher in patients compared with controls (p<0.0005 and p<0.0001, respectively). All growth factors, except for IGFBP‐2, correlated with parameters of liver function. In a multiple regression analysis, adjusting for age, no correlation was found between IGF‐I, IGF‐II, IGFBP‐1–3 and BMD in either patients or controls. Conclusion: Patients with CLD have low levels of IGF‐I, IGF‐II and IGFBP‐3 that correlate with liver function. No relationship was found between low levels of growth factors and BMD.
HLA class II alleles in Chinese patients with hepatocellular carcinoma
Authors: Donaldson P. T. , Ho S. , Williams R. , Johnson P. J.
Published: March 2003

Abstract: Background/Aims: Recent reports of an association between human leucocyte antigens (HLA) and persistence of hepatitis B virus infection, and the familial clustering of hepatocellular carcinoma raise the question of genetic susceptibility. Previous studies have been limited to serological phenotyping of HLA B and DR antigens. The aim of this study was to use molecular genotyping to investigate HLA class II as a risk factor for the development of hepatocellular carcinoma in Hong Kong Chinese. Methods: We determined HLA DRB1, DQA1, DQB1 and DPB1 alleles in 123 hepatitis B surface antigen positive patients (84 with hepatocellular carcinoma and 39 without) and 124 matched controls. Results: The alleles DRB1*1501 (36% of HCC patients versus 19% of controls, odds ratio=2.44), DQA1*0102 (42% versus 26%, odds ratio=2.07), and DPB1*0501 (80% versus 63%, odds ratio=2.35) were significantly more common in patients with hepatocellular carcinoma, and DQA1*03 (36% versus 56%, odds ratio=0.53), DQB1*0302 (4.% versus 13%, odds ratio=0.25) and DPB1*0201 (14% versus 29%, odds ratio=0.4) were found at significantly lower frequencies. Conclusions: Although none of these associations was significant after correction for multiple testing, this report suggests that further investigations are warranted.