Cilia Ultrastructure Associated with Primary Ciliary Dyskinesia in Omani Patients

Objectives

Primary ciliary dyskinesia (PCD) is a disorder affecting the structure and function of the motile cilia of the respiratory system. Transmission electron microscopy is one method that can be used to examine ciliary ultrastructure in airway biopsies. Although the role of ultrastructural findings in PCD has been described in the literature, this role has not been well-studied in the Middle East or, specifically, Oman. This study aimed to describe ultrastructural features in Omani patients with high suspicion of PCD.

Methods

This retrospective cross-sectional study included 129 adequate airway biopsies obtained from Omani patients attending pulmonary clinics at Sultan Qaboos University Hospital and the Royal Hospital, Muscat, Oman, from 2010 to 2020 who were suspected of having PCD.

Results

Ciliary ultrastructural abnormalities in the current study population were outer dynein arm (ODA) associated with inner dynein arm (IDA) defects (8%), microtubular disorganisation associated with IDA defect (5%) and isolated ODA defect (2%). Most of the biopsies showed normal ultrastructure (82%).

Conclusion

In Omani patients suspected to have PCD, normal ultrastructure was the most common feature.

The Association of Human Leukocyte Antigens Complex with Type 1 Diabetes in the Omani Population

Objectives

Identification of the high risk alleles, genotypes and haplotypes of the human leukocyte antigens (HLA) in different populations is beneficial for understanding their roles in type 1 diabetes (T1D) pathogenesis and intervention practices. This study aimed to identify T1D-associated HLA gene alleles in the Omani population.

Methods

The present case-control study included 73 diabetic seropositive children (mean age 9.08 ± 3.27 years) attending the paediatric clinic at Sultan Qaboos University Hospital in Muscat, Oman, and 110 healthy controls. HLA-A, -B, -C, -DRB1 and -DQB1 genes were genotyped using a sequence-specific primer polymerase chain reaction (SSP-PCR).

Results

Two HLA class I alleles (B*08, B*58) and three class II alleles (DQB1*02, DRB1*03 and DRB1*04) were associated with T1D susceptibility, while one class I (B*51) and three class II (DQB1*05, DQB1*06 and DRB1*16) alleles were associated with T1D protection. HLA-DRB1*03 and DQB1*02 alleles showed the strongest risk association among all alleles. Six DRB1 residues (E⁹, S¹¹, S¹³, Y³⁰, V⁷⁰ and K⁷¹) were significantly associated with T1D susceptibility. Heterozygous genotypes, HLA-DRB1*03/*04 and DQB1*02/*03 were significantly associated with T1D susceptibility (P <0.0001, odds ratio [OR] = 63.21 and P = 0.02, OR = 3.63, respectively). Furthermore, a significant combined action of DRB1*03-DQB1*02 haplotype in T1D risk (P = 0.000176, OR = 15) and DRB1*16-DQB1*05 haplotype in protection (P = 0.0312, OR = 0.48) was detected.

Conclusion

Known HLA class II gene alleles are associated with T1D in Omani children.

Immunological Responses to Injury and Grafting in the Central Nervous System of Nonhuman Primates

Allogeneic transplantation for the therapy of human Parkinson's disease is being considered as a viable approach at several clinical centers worldwide. As an attempt to understand the basic biology of central nervous system (CNS) transplantation, our laboratory has developed an experimental nonhuman primate model for human Parkinson's disease and carried out preliminary studies directed at evaluating the potential pathology at the graft site. In addition, studies have been conducted to examine whether such transplantation procedures lead to specific and/or nonspecific immunologic sensitization of the host or results in generalized immunosuppression. Groups of rhesus macaques (Macaca mulatta) were either controls operated (n = 6), autografted with adrenal medullary and peripheral nerve tissue (n = 3), or allografted with fetal mesencephalic tissue (n = 6). Immunohistological studies demonstrated the presence of mononuclear cell infiltrates as early as 1 wk and up to 1 yr postoperatively, although the frequency of the infiltrating cells declined with time. The infiltrates consisted of variable numbers of cells which express CD2+, CD3+, CD4+, CD8+, CD19+, CD22+, CD25+, and CD68+. There appeared to be no difference in the frequency, kinetics, or phenotype of the infiltrating cells in operative controls compared with recipients of auto- or allografts. Tissue sections obtained postoperatively showed low levels of major histocompatibility complex (MHC) Class I antigens and no detectable level of MHC-Class II antigens in neural tissue. A small aliquot of tissue from the operative site was placed in vitro with media containing interleukin-2 (IL-2), which led to the exudation and growth of mononuclear cells that were predominantly CD4+ cells. Phenotypic studies of peripheral blood mononuclear cells (PBMC) from operative controls, auto- and allograft recipient monkeys performed at varying time periods postoperatively failed to show differences in the frequencies of subsets of T-cells, B-cells, NK-cells, or monocytes. Studies on aliquots of the same PBMC failed to show major functional differences in NK-cells, LAK cells, or response to polyclonal mitogens. Finally, recipients of allogeneic mesencephalic grafts failed to show evidence of donor-specific humoral or cellular sensitization. These data indicate that transplantation of autograft adrenal or allograft fetal mesencephalic tissues in the CNS of nonhuman primate did not induce detectable donor-specific sensitization nor nonspecific immunosuppression.

Endogenous interleukin-22 protects against inflammatory bowel disease but not autoimmune cholangitis in dominant negative form of transforming growth factor beta receptor type II mice

During chronic inflammation, interleukin (IL)-22 expression is up-regulated in both CD4 and CD8 T cells, exerting a protective role in infections. However, in autoimmunity, IL-22 appears to have either a protective or a pathogenic role in a variety of murine models of autoimmunity and, by extrapolation, in humans. It is not clear whether IL-22 itself mediates inflammation or is a by-product of inflammation. We have taken advantage of the dominant negative form of transforming growth factor beta receptor type II (dnTGF-βRII) mice that develop both inflammatory bowel disease and autoimmune cholangitis and studied the role and the biological function of IL-22 by generating IL-22(-/-) dnTGF-βRII mice. Our data suggest that the influence of IL-22 on autoimmunity is determined in part by the local microenvironment. In particular, IL-22 deficiency exacerbates tissue injury in inflammatory bowel disease, but has no influence on either the hepatocytes or cholangiocytes in the same model. These data take on particular significance in the previously defined effects of IL-17A, IL-12p40 and IL-23p19 deficiency and emphasize that, in colitis, there is a dominant role of IL-23/T helper type 17 (Th17) signalling. Furthermore, the levels of IL-22 are IL-23-dependent. The use of cytokine therapy in patients with autoimmune disease has significant potential, but must take into account the overlapping and often promiscuous effects that can theoretically exacerbate inflammation.

Immunological potential of cytotoxic T lymphocyte antigen 4 immunoglobulin in murine autoimmune cholangitis

Cytotoxic T lymphocyte antigen 4 (CTLA-4) immunoglobulin (Ig) is an important regulator of T cell activation and a fusion protein directed at CD80 and CD86; it blocks co-stimulatory signalling and T cell activation. We have taken advantage of a murine model of human primary biliary cirrhosis (PBC), mice expressing a transforming growth factor (TGF)-β receptor II dominant negative (dnTGF-βRII) transgene to address the potential therapeutic efficacy of CTLA-4 Ig. To mimic patients with PBC at different stages or duration of disease, we treated mice with either CTLA-4 Ig or control IgG three times weekly from 3 to 12 or 24 weeks of age, or from 12 to 24 weeks of age. CTLA-4 Ig treatment from 3 weeks of age significantly reduced liver inflammation to 12 weeks of age. Treatment initiated at 12 weeks of age also ameliorated the autoimmune cholangitis at 24 weeks of age. However, in mice treated at 3 weeks of age, suppression of liver inflammation was not sustained and colitis was aggravated when treatment was extended to 24 weeks of age. Our data indicate that, in dnTGF-βRII mice, CTLA-4 Ig treatment has short-term beneficial effects on autoimmune cholangitis, but the effect varies according to duration of treatment and the time in which therapy was initiated. Further dissection of the events that lead to the reduction in therapeutic effectiveness of CTLA-4 Ig will be critical to determining whether such efforts can be applied to human PBC.

Successful immunotherapy of autoimmune cholangitis by adoptive transfer of forkhead box protein 3(+) regulatory T cells

Treatment of primary biliary cirrhosis (PBC) has lagged behind that of other autoimmune diseases. In this study we have addressed the potential utility of immunotherapy using regulatory T cells (Treg ) to treat murine autoimmune cholangitis. In particular, we have taken advantage of our ability to produce portal inflammation and bile duct cell loss by transfer of CD8(+) T cells from the dominant negative form of transforming growth factor beta receptor type II (dnTGF-βRII) mice to recombination-activating gene (Rag)1(-/-) recipients. We then used this robust established adoptive transfer system and co-transferred CD8(+) T cells from dnTGF-βRII mice with either C57BL/6 or dnTGF-βRII forkhead box protein 3 (FoxP3(+) ) T cells. Recipient mice were monitored for histology, including portal inflammation and intralobular biliary cell damage, and also included a study of the phenotypical changes in recipient lymphoid populations and local and systemic cytokine production. Importantly, we report herein that adoptive transfer of Treg from C57BL/6 but not dnTGF-βRII mice significantly reduced the pathology of autoimmune cholangitis, including decreased portal inflammation and bile duct damage as well as down-regulation of the secondary inflammatory response. Further, to define the mechanism of action that explains the differential ability of C57BL/6 Treg versus dnTGF-βRII Treg on the ability to down-regulate autoimmune cholangitis, we noted significant differential expression of glycoprotein A repetitions predominant (GARP), CD73, CD101 and CD103 and a functionally significant increase in interleukin (IL)-10 in Treg from C57BL/6 compared to dnTGF-βRII mice. Our data reflect the therapeutic potential of wild-type CD4(+) FoxP3(+) Treg in reducing the excessive T cell responses of autoimmune cholangitis, which has significance for the potential immunotherapy of PBC.

Influence of Gd3+ co-doping on structural property of CaMoO4:Eu nanoparticles

A facile auto-combustion route is used for the synthesis of Gd(3+) (2, 5, 7 and 10 at%) co-doped CaMoO4:Eu nanoparticles. X-ray diffraction study suggests that as-prepared samples have extra impurity phases in addition to main tetragonal phase of CaMoO4, and such extra phases decrease as the annealing temperature increases from 600 to 900 °C. The crystal structure has been analysed using Rietveld program. It has space group I4₁/a (88) and Z = 4 (number of CaMoO4 formula units per unit cell). Average crystallite sizes of as-prepared, 600 and 900 °C annealed samples for 2 at% Gd(3+) are found to be ~33, 48 and 61 nm, respectively. The lattice strains of 5 at% Gd(3+) co-doped CaMoO4:Eu for as-prepared and 900 °C are 0.001 and 0.002, respectively. Fourier transform infrared spectroscopy gives the absorption bands at ~815 and 427 cm(-1), which are related to asymmetric stretching and bending vibrations of MoO4(2-) tetrahedron. Particle morphology is studied using scanning and transmission electron microscopy (SEM and TEM), and aggregation of particles is found. X-ray photoelectron spectroscopy (XPS) is utilized to examine the oxidation states of metal ions/oxygen and oxygen ion vacancies in Gd(3+) co-doped CaMoO4:Eu. With an increase in Gd(3+) concentration, peaks corresponding to the Gd(3+) (2p(3/2) and 2p(5/2)) binding energy could be detected.

Enhanced photoluminescence in CaMoO4:Eu3+ by Gd3+ co-doping

We have studied the luminescence property of CaMoO4:Eu(3+). The emission peaks at 590 ((5)D0→(7)F1) and 613 nm ((5)D0→(7)F2) for Eu(3+) are observed after excitation at 266 nm (i.e. Mo-O charge transfer band). The peak intensity of the latter dominates over the former indicating an asymmetric environment of Eu(3+) in EuO8 polyhedron or parity mixing. Luminescence intensity increases significantly with co-doping of Gd(3+). This is ascribed to energy transfer from Mo-O/Gd(3+) to Eu(3+). Luminescence intensity increases with annealing up to 900 °C due to the extent of decrease of non-radiative rates. Very high asymmetric values (A21) of 12-16 are found indicating a red emitter. As-prepared samples are dispersible in polar solvents like water, ethanol, methanol, dimethyl sulfoxide (DMSO) and ethylene glycol (EG); and among them, optimum luminescence is found in methanol. Polymer film shows red emission. The quantum yields of as-prepared 2 and 10 at% Gd(3+) co-doped CaMoO4:Eu(3+) under 277 nm (UV excitation) are 21 and 80%, respectively.

Innate immunity drives xenobiotic-induced murine autoimmune cholangitis

Although primary biliary cirrhosis (PBC) is considered a model autoimmune disease, it has not responded therapeutically to traditional immunosuppressive agents. In addition, PBC may recur following liver transplantation, despite the absence of major histocompatibility complex (MHC) matching, in sharp contrast to the well-known paradigm of MHC restriction. We have suggested previously that invariant natural killer T (iNK T) cells are critical to the initiation of PBC. In this study we have taken advantage of our ability to induce autoimmune cholangitis with 2-octynoic acid, a common component of cosmetics, conjugated to bovine serum albumin (2-OA-BSA), and studied the natural history of pathology in mice genetically deleted for CD4 or CD8 following immunization with 2-OA-BSA in the presence or absence of α-galactosylceramide (α-GalCer). In particular, we address whether autoimmune cholangitis can be induced in the absence of traditional CD4 and CD8 responses. We report herein that CD4 and CD8 knock-out mice immunized with 2-OA-BSA/PBS or 2-OA-BSA/α-GalCer develop anti-mitochondrial antibodies (AMAs), portal infiltrates and fibrosis. Indeed, our data suggest that the innate immunity is critical for immunopathology and that the pathology is exacerbated in the presence of α-GalCer. In conclusion, these data provide not only an explanation for the recurrence of PBC following liver transplantation in the absence of MHC compatibility, but also suggest that effective therapies for PBC must include blocking of both innate and adaptive pathways.

Enhanced luminescence of CaMoO₄:Eu by core@shell formation and its hyperthermia study after hybrid formation with Fe₃O₄: cytotoxicity assessment on human liver cancer cells and mesenchymal stem cells

Highly water dispersible Eu³⁺ doped CaMoO₄ nanoparticles (core) covered by CaMoO₄ (shell) have been prepared using the polyol method. Significant enhancement in luminescence intensity by core@shell formation is observed due to the decrease of non-radiative rate arising from surface/defect of particles. Effect of 266 nm laser excitation (Mo-O charge transfer band) on the asymmetric ratio (A₂₁ = intensity ratio of electric to magnetic dipole transitions) has been studied and compared with a xenon lamp source. Luminescence intensity increases with the increase of power at 532 nm laser excitation. In order to explore materials, which can show dual functionalities such as luminescence as well as magnetic properties (magnetization of ∼14.2 emu g⁻¹), water dispersible Fe₃O₄-CaMoO₄:Eu hybrid magnetic nanoparticles (MN) have been prepared. This shows good heating ability up to ∼42 °C (hyperthermia) and luminescence in the red region (∼612 nm), which is in a biological window (optical imaging). Biocompatibility of the synthesized Fe₃O₄-CaMoO₄:Eu hybrid magnetic nanoparticles has been evaluated in vitro by assessing their cytotoxicity on human liver cancer cells (HepG2 cells) and hTERT cells using the MTT assay and fluorescent microscopy studies.

Anti-CD40 ligand monoclonal antibody delays the progression of murine autoimmune cholangitis

While there have been significant advances in our understanding of the autoimmune responses and the molecular nature of the target autoantigens in primary biliary cirrhosis (PBC), unfortunately these data have yet to be translated into new therapeutic agents. We have taken advantage of a unique murine model of autoimmune cholangitis in which mice expressing a dominant negative form of transforming growth factor β receptor II (dnTGFβRII), under the control of the CD4 promoter, develop an intense autoimmune cholangitis associated with serological features similar to human PBC. CD40-CD40 ligand (CD40L) is a major receptor-ligand pair that provides key signals between cells of the adaptive immune system, prompting us to determine the therapeutic potential of treating autoimmune cholangitis with anti-CD40L antibody (anti-CD40L; MR-1). Four-week-old dnTGFβRII mice were injected intraperitoneally with either anti-CD40L or control immunoglobulin (Ig)G at days 0, 2, 4 and 7 and then weekly until 12 or 24 weeks of age and monitored for the progress of serological and histological features of PBC, including rigorous definition of liver cellular infiltrates and cytokine production. Administration of anti-CD40L reduced liver inflammation significantly to 12 weeks of age. In addition, anti-CD40L initially lowered the levels of anti-mitochondrial autoantibodies (AMA), but these reductions were not sustained. These data indicate that anti-CD40L delays autoimmune cholangitis, but the effect wanes over time. Further dissection of the mechanisms involved, and defining the events that lead to the reduction in therapeutic effectiveness will be critical to determining whether such efforts can be applied to PBC.

Human intrahepatic biliary epithelial cells engulf blebs from their apoptotic peers

The phagocytic clearance of apoptotic cells is critical for tissue homeostasis; a number of non-professional phagocytic cells, including epithelial cells, can both take up and process apoptotic bodies, including the release of anti-inflammatory mediators. These observations are particularly important in the case of human intrahepatic biliary cells (HiBEC), because such cells are themselves a target of destruction in primary biliary cirrhosis, the human autoimmune disease. To address the apoptotic ability of HiBECs, we have focused on their ability to phagocytize apoptotic blebs from autologous HiBECs. In this study we report that HiBEC cells demonstrate phagocytic function from autologous HiBEC peers accompanied by up-regulation of the chemokines CCL2 [monocyte chemotactic protein-1 (MCP-1)] and CXCL8 [interleukin (IL)-8]. In particular, HiBEC cells express the phagocytosis-related receptor phosphatidylserine receptors (PSR), implying that HiBECs function through the 'eat-me' signal phosphatidylserine expressed by apoptotic cells. Indeed, although HiBEC cells acquire antigen-presenting cell (APC) function, they do not change the expression of classic APC function surface markers after engulfment of blebs, both with and without the presence of Toll-like receptor (TLR) stimulation. These results are important not only for understanding of the normal physiological function of HiBECs, but also explain the inflammatory potential and reduced clearance of HiBEC cells following the inflammatory cascade in primary biliary cirrhosis.

Mycotoxin production by some IndianAlternaria species

A total of seven species ofAlternaria: A. alternata (Fr.) Keissler;A. capsici-annui Savul & Sandu;A. citri Ellis & Pierce;A. porri (Ellis) Clfferi;A. radicina Meler, Drechsler & Eddy;A. tenuissima (Kunze: Pers) Wiltshire andA. tomato (Cooke) Jones were screened on rice culture medium for their ability to elaborate five majorAlternaria mycotoxins viz. tenuazonlc acid (TA), alternariol (AOH), alternariol methyl ether (AME), altenuene (ALT) and altertoxin-l (ATX-I). All the species produced mycotoxins in varying concentrations. A.capsici-annul was recorded as the mycotoxin producer for the first time. ALT byA. citri andA. tomato; ALT, and ATX-I byA. tenuissima; ALT, TA and AME byA. porri and TA byA. radicina are the new additions to the list of mycotoxins produced by the respective species ofAlternaria.

The role of natural killer (NK) and NK T cells in the loss of tolerance in murine primary biliary cirrhosis

One of the major obstacles in dissecting the mechanism of pathology in human primary biliary cirrhosis (PBC) has been the absence of animal models. Our laboratory has focused on a model in which mice, following immunization with a xenobiotic chemical mimic of the immunodominant autoepitope of the E2 component of pyruvate dehydrogenase complex (PDC-E2), develop autoimmune cholangitis. In particular, following immunization with 2-octynoic acid (a synthetic chemical mimic of lipoic acid-lysine located within the inner domain of PDC-E2) coupled to bovine serum albumin (BSA), several strains of mice develop typical anti-mitochondrial autoantibodies and portal inflammation. The role of innate immune effector cells, such as natural killer (NK) cells and that NK T cells, was studied in this model based on the hypothesis that early events during immunization play an important role in the breakdown of tolerance. We report herein that, following in-vivo depletion of NK and NK T cells, there is a marked suppression of anti-mitochondrial autoantibodies and cytokine production from autoreactive T cells. However, there was no change in the clinical pathology of portal inflammation compared to controls. These data support the hypothesis that there are probably multiple steps in the natural history of PBC, including a role of NK and NK T cells in initiating the breakdown of tolerance. However, the data suggest that adaptive autoimmune effector mechanisms are required for the progression of clinical disease.

The role of natural killer (NK) and NK T cells in the loss of tolerance in murine primary biliary cirrhosis

One of the major obstacles in dissecting the mechanism of pathology in human primary biliary cirrhosis (PBC) has been the absence of animal models. Our laboratory has focused on a model in which mice, following immunization with a xenobiotic chemical mimic of the immunodominant autoepitope of the E2 component of pyruvate dehydrogenase complex (PDC-E2), develop autoimmune cholangitis. In particular, following immunization with 2-octynoic acid (a synthetic chemical mimic of lipoic acid-lysine located within the inner domain of PDC-E2) coupled to bovine serum albumin (BSA), several strains of mice develop typical anti-mitochondrial autoantibodies and portal inflammation. The role of innate immune effector cells, such as natural killer (NK) cells and that NK T cells, was studied in this model based on the hypothesis that early events during immunization play an important role in the breakdown of tolerance. We report herein that, following in-vivo depletion of NK and NK T cells, there is a marked suppression of anti-mitochondrial autoantibodies and cytokine production from autoreactive T cells. However, there was no change in the clinical pathology of portal inflammation compared to controls. These data support the hypothesis that there are probably multiple steps in the natural history of PBC, including a role of NK and NK T cells in initiating the breakdown of tolerance. However, the data suggest that adaptive autoimmune effector mechanisms are required for the progression of clinical disease.

Epitope-specific anti-nuclear antibodies are expressed in a mouse model of primary biliary cirrhosis and are cytokine-dependent

Although the hallmark of primary biliary cirrhosis (PBC) is the presence of anti-mitochondrial antibodies (AMA), a significant number of patients have anti-nuclear antibodies (ANA) directed primarily against two nuclear proteins, gp210 and sp100. In PBC, there are considerable data on the specificity of these anti-nuclear antibodies as well as suggestive evidence that antibodies to gp210 predict a poor outcome. However, a further understanding of the significance of these autoantibodies has been hampered by limitations in accessing human subjects in a preclinical or early asymptomatic stage. To overcome this limitation, we have taken advantage of transgenic mice with abrogated transforming growth factor-β signalling in T cells (dnTGF-βRII) that develop histological features of PBC as well as the same AMA specificity. We studied these mice for serum ANA, including specific autoantibodies against gp210 and sp100. We further examined sera from dnTGF-βRII mice with concurrent deletions of the genes encoding interleukin (IL)-12p35, IL-12p40, IL-23p19, IL-17, IL-6, interferon (IFN)-γ or tumour necrosis factor (TNF)-α. Sera from all the dnTGF-βRII mouse lines contained antibodies against gp210 and sp100. Of significance, mice with germline deletions of the genes encoding IL-12p40, IL-23p19, IL-17, IL-6 and TNF-α had significantly lower titres of anti-gp210 antibodies. These results provide a platform to dissect the mechanisms of gp210 and sp100 autoantibody production in dnTGF-βRII mice as well as to study the possible role of ANA in the pathophysiology of PBC.

Increased inherent intestinal granzyme B expression may be associated with SIV pathogenesis in Asian non-human primates

BACKGROUND

Unlike Asian non-human primates, chronically SIV-infected African non-human primates (NHP) display a non-pathogenic disease course. The different outcomes may be related to the development of an SIV-mediated breach of the intestinal mucosa in the Asian species that is absent in the African animals.

METHODS

To examine possible mechanisms that could lead to the gut breach, we determined whether the colonic lamina propria (LP) of SIV-naïve Asian monkeys contained more granzyme B (GrB) producing CD4 T cells than did that of the African species. GrB is a serine protease that may disrupt mucosal integrity by damaging tight junction proteins.

RESULTS

We found that the colonic LP of Asian NHP contain more CD4(+) /GrB(+) cells than African NHP. We also observed reduced CD4 expression on LP T cells in African green monkeys.

CONCLUSION

Both phenotypic differences could protect against SIV-mediated damage to the intestinal mucosa and could lead to future therapies in HIV(+) humans.

The multi-hit hypothesis of primary biliary cirrhosis: polyinosinic-polycytidylic acid (poly I:C) and murine autoimmune cholangitis

A void in understanding primary biliary cirrhosis (PBC) is the absence of appropriate animal models. Our laboratory has studied a murine model of autoimmune cholangitis induced following immunization with 2-octynoic acid (2OA), an antigen identified following extensive quantitative structural activity relationship (QSAR) analysis, using human autoantibodies and three-dimensional analysis of the mitochondrial autoantigen, the E2 subunit of the pyruvate dehydrogenase complex (PDC-E2). Mice immunized with 2OA coupled to bovine serum albumin (BSA) develop anti-mitochondrial antibodies (AMAs) of the identical specificity as humans with PBC, and in addition develop inflammatory portal cell infiltrates in liver. However, the natural history of disease is less severe than in humans and does not include fibrosis. Data from human and autoimmune murine models suggest that environmental and/or infectious agents can exacerbate autoimmune reactions, and a model of PBC has been described in which polyinosinic-polycytidylic acid (poly I:C), a viral RNA mimetic and Toll-like receptor 3 (TLR-3) agonist induces low-titre AMAs and in mild portal infiltrates. We took advantage of our established model to determine whether immunization with 2OA-BSA coupled with poly I:C alters the disease process. Indeed, the addition of poly I:C produces a profound exacerbation of autoimmune cholangitis, including a significant increase in CD8(+) infiltrating T cells, as well as a marked increase of proinflammatory cytokines. In addition, mice have evidence of fibrosis. These findings lend support to the concept that besides breakdown of self-tolerance, there is a requirement of a second 'hit' during the breakdown process that leads to disease which more faithfully mimics human PBC.

Modulation of CD4⁺ T cell responses following splenectomy in hepatitis C virus-related liver cirrhosis

Dysfunction of T cells is a common feature in chronic persistent viral infections, including hepatitis C virus (HCV), and although hepatic and peripheral T cells have been studied extensively in chronic HCV hepatitis, the role of splenic T cell responses in such patients is poorly defined. This is an important issue, as thrombocytopenia is a complication of HCV-related liver cirrhosis (LC), due to splenic platelet sequestration and bone marrow suppression; splenectomy has been proposed to treat such patients. Herein, we studied peripheral blood mononuclear cells (PBMC) and splenic lymphoid subpopulations from a total of 22 patients, including 15 with HCV-related LC with marked thrombocytopenia treated with splenectomy, and seven controls. CD4(+) T cells from peripheral blood and spleen were isolated and phenotype and function evaluated. Splenic CD4(+) T cells in patients with LC expressed molecules associated with inhibitory signalling, including increased frequency of negative markers such as cytotoxic T lymphocyte associated antigen-4 (CTLA-4) and programmed death 1 (PD-1) and decreased production of cytokines. Patients with LC manifest higher levels of splenic CD4(+) regulatory T cells and PD-L1- and PD-L2-expressing cells than controls. Blocking of PD-1/PD-1 ligand interaction reconstituted proliferative and cytokine responses of splenic mononuclear cells (SMC) from patients with LC. Splenectomy was followed by an increase in the ratio of interferon (IFN)-γ to interleukin (IL)-10 and a reduction of PD-1-expressing CD4(+) T cells in peripheral blood. Our data suggest that peripheral tolerance is promoted by the spleen in LC via the up-regulated expression of PD-1 ligands.

Induction of autoimmune cholangitis in non-obese diabetic (NOD).1101 mice following a chemical xenobiotic immunization

Our laboratory has suggested that loss of tolerance to pyruvate dehydrogenase (PDC-E2) leads to an anti-mitochondrial antibody response and autoimmune cholangitis, similar to human primary biliary cirrhosis (PBC). We have suggested that this loss of tolerance can be induced either via chemical xenobiotic immunization or exposure to select bacteria. Our work has also highlighted the importance of genetic susceptibility. Using the non-obese diabetic (NOD) congenic strain 1101 (hereafter referred to as NOD.1101 mice), which has chromosome 3 regions from B6 introgressed onto a NOD background, we exposed animals to 2-octynoic acid (2OA) coupled to bovine serum albumin (BSA). 2OA has been demonstrated previously by a quantitative structural activity relationship to react as well as or better than lipoic acid to anti-mitochondrial antibodies. We demonstrate herein that NOD.1101 mice immunized with 2OA-BSA, but not with BSA alone, develop high titre anti-mitochondrial antibodies and histological features, including portal infiltrates enriched in CD8(+) cells and liver granulomas, similar to human PBC. We believe this model will allow the rigorous dissection of early immunogenetic cause of biliary damage.

Optical absorption spectroscopic studies on holmium(III) complexes with beta-diketone and heterocyclic amines: the environment effect on 4f-4f hypersensitive transitions

The optical absorption spectra of [Ho(acac)(3)(H(2)O)(2)].H(2)O, [Ho(acac)(3)phen] and [Ho(acac)(3)bpy] (where acac is the anion of acetylacetone; phen is 1,10-phenanthroline and bpy is 2,2'-bipyridyl) complexes in the visible region, in a series of non-aqueous solvents (methanol, ethanol, isopropanol, chloroform, acetonitrile and pyridine.) have been analyzed. The largest intensity variation was observed in the (5)G(6)<--(5)I(8) (centered at 450 nm), and (5)G(5), (3)H(5), (3)H(6)<--(5)I(8) (centered at 360 nm) transition regions. The band shape and oscillator strength of the hypersensitive transitions display pronounced changes as compared to Ho(3+) aqua-ion. The band shapes of the hypersensitive transitions show remarkable changes on passing from aqueous solution to various non-aqueous solutions which is the result of change in the environment about the Ho(III) ion in the various solutions and suggests coordination of solvent molecule(s), in some cases. The results clearly show that among the solvents studied pyridine is the most effective in promoting the 4f-4f spectral intensity. It has been inferred from this study that 2,2'-bipyridyl is a stronger ligand for heavier lanthanides. A comparative account of hypersensitivity in the present complexes with those of other adducts of Ho(beta-diketoenolate)(3) with heterocyclic amines is discussed. The TGA analyses showed that the phen complex is thermally more stable over its bpy analogue.

Molecular genetics of human immune responsiveness to allergens

Specific immune responsiveness to certain highly purified allergens is significantly associated with particular HLA-D types. In one striking example, IgE and IgG responsiveness to the ragweed Amb V (Ra5) allergens is strongly associated with HLA-DR2/Dw2. We studied the HLA-D gene sequences of 67 Caucasoid subjects. All Dw2+ (Dw2 +/- in one case) high responders to Amb a V, before or after high-dose ragweed immunotherapy, possessed typical DRB1*2.2 and DRB3*2.2 (Dw2-associated DR beta) gene sequences. Their DQB1 genes all had typical Dw2-associated DQB1*1.2 sequences, with two exceptions (DQB1*1.21 and DQB1*1.18, that are usually associated with Dw21 and Dw18, respectively). The finding of these unusual sequence combinations in these Amb a V responders implicates a DR alpha beta I2.2 or a DR alpha beta III2.2 molecule as the major Amb a V Ir gene product. This conclusion is supported by our finding of one non-responder (after prolonged immunotherapy) who possessed the DQ1.2, but not the DR2.2, sequences. In ragweed-allergic subjects further data suggest that a DR2.2 molecule is generally a necessary and almost always a sufficient requirement for high Amb a V responsiveness. An Amb a V-specific T cell clone obtained from a Dw2+ subject was DR-restricted according to inhibition studies using anti-HLA-D monoclonal antibodies. Also, antigen-presenting cells that were DR2.2+ or DR2.12+, but not DR2.21+ or DR2.22+, were able to present antigen to the cloned T cells, implicating certain DR2 molecules as restriction elements. In similar studies using the rye grass allergen Lol p III we obtained preliminary data implicating the DR beta I sequence E9 YSTS13 (found in DR3, DR5 and DRw6 genotypes) in the recognition of a major Lol p III agretope. Since Lol p I and II are homologous to Lol p III in one region of their amino acid sequences the EYSTS sequence may also be involved in the recognition of similar agretopes of these molecules. These and other studies demonstrate the power of the allergy model for genetic and molecular studies of the human immune response.

Generation of functionally distinct B lymphocytes from common myeloid progenitors

Current models of adult haematopoiesis propose that haematopoietic stem cells (HSCs) differentiate into common lymphoid (CLP) and common myeloid (CMP) progenitors and establish an early separation between myeloid and lymphoid lineages. Nevertheless, the developmental potential of CMP-associated B cells suggests the existence of alternate pathways for B lymphopoesis. The aim of this study was to compare the developmental and functional properties of CMP- and CLP-derived B cells. While both populations matured through pro-B cell and transitional B cell intermediates in the bone marrow and spleen, respectively, following transfer into irradiated mice, mature CMP- and CLP-derived B cells exhibit distinct functional responses. Specifically, CMP-derived B cells did not respond to mitogenic stimulation to the same degree as their CLP-derived counterparts and secrete lower levels of IgM and the inflammatory cytokines such as interleukin (IL)-6 and IL-10. Together, these data suggest the existence of multiple pathways for generating functionally distinct B cells from bone marrow precursors.

Nuclear magnetic resonance and optical absorption spectroscopic studies on paramagnetic praseodymium(III) complexes with beta-diketone and heterocyclic amines

The optical absorption spectra of [Pr(acac)(3)(H(2)O)(2)].H(2)O, [Pr(acac)(3)phen.H(2)O] and [Pr(acac)(3)bpy] (where acac is the anion of acetylacetone, phen is 1,10-phenanthroline and bpy is 2,2'-bipyridyl) have been analyzed in the visible region in a series of non-aqueous solvents (methanol, ethanol, isopropanol, chloroform, acetonitrile and pyridine). The complexes display four non-hypersensitive 4f-4f transitions ((3)P(2), (3)P(1)+(1)I(6), (3)P(0) and (1)D(2)) from the (3)H(4) ground state. The band shape of the transitions shows remarkable changes upon dissolving in different solvents. Distinctively different band shapes have been observed for phen and bpy complexes. The phen is more effective in producing changes and the splitting of the bands is more pronounced in phen complex since it is a stronger ligand and leads to stronger Pr-N(phen) bond. The splitting of the bands is indicative of partaking of f-orbitals in bonding. The NMR signals of heterocyclic amines have been shifted to high fields while the resonances due to acetylacetone moiety have moved to low fields which is the consequence of change in geometry of the complexes upon coordination of the heterocyclic amines and reflects the importance of geometric factor (3cos(2)theta-1) in changing sign of the shift and to a good approximation the shifts arise predominantly from the dipolar mechanism. The phen complexes have narrower line width than bpy complexes. The line broadening in the case of bpy complexes is suggestive of exchange between inter-converting forms. The bpy possesses some degree of rotational freedom about C(6)-C(6') bond and the two pyridine rings undergo scissoring motion with respect to each other.

Optical absorption and NMR spectroscopic studies on paramagnetic neodymium(III) complexes with beta-diketone and heterocyclic amines. The environment effect on 4f-4f hypersensitive transitions

The optical absorption spectra of [Nd(acac)3(H2O)2].H2O, [Nd(acac)3bpy] and [Nd(acac)3phen(H2O)2] (where acac=acetylacetone, bpy=2,2'-bipyridyl and phen=1,10-phenanthroline) complexes in the visible region, in a series of non-aqueous solvents (methanol, ethanol, isopropanol, chloroform, acetonitrile, pyridine, nitrobenzene and dimethylsulphoxide) have been analyzed. The transition 4G(5/2)<--4I(9/2) (Nd-VI) located near the middle of the visible region (17,500 cm(-1)) is hypersensitive. Its behavior is in sharp contrast to many other typically weak and consistently unvaried, normal 4f-4f transitions. The oscillator strength of this transition for the chelate as well as its adducts with phen and bpy in any of the solvent employed is larger than the oscillator strength of Nd3+ aqua-ion. It is most intense in pyridine for all the complexes studied and, therefore, pyridine is the most effective in promoting f-f spectral intensity. The band shape and oscillator strength of the hypersensitive transitions display pronounced changes as compared to Nd3+ aqua-ion. The band shapes of the hypersensitive transitions show remarkable changes on passing from aqueous solution to various non-aqueous solutions, which is the result of change in the environment about the Nd(III) ion in the various solutions and suggests change in the environment about the Nd(III) ion in the various solutions and suggests coordination of solvent molecule(s), in some cases. A comparative account of hypersensitivity in the present complexes with those of other adducts of Nd(beta-diketoenolate)3 with heterocyclic amines is discussed. The NMR signals of heterocyclic amines have been shifted to high fields while the resonances due to acetylacetone moiety have moved to low fields. The paramagnetic shift in the complexes is dipolar in nature.

The role of CD11c(+) hepatic dendritic cells in the induction of innate immune responses

The role of the liver in the initiation and maintenance of tolerance is a critical immune function that involves multiple lineages of immune cells. Included within these populations are liver dendritic cells (DCs). Although there has been significant work on the phenotypic and functional roles of splenic and bone marrow dendritic cells, as well as their subsets, comparable studies in liver have often been difficult. To address this issue we have isolated, from C57BL/6 mice, relatively pure populations of DCs and compared phenotype and function to the data from spleen using flow cytometry, cell sorter assisted purification and culture, morphology by cytospin and May-Giemsa staining, cell cycle progression, antigen uptake, cytokine production and allo-activation potential. natural killer (NK)1.1(-)CD11c(+) liver DC subsets (conventional DCs, T cell receptor (TcR)beta(-)NK1.1(-)CD11c(+)B220(-) and plasmacytoid DCs, TcRbeta(-)NK1.1(-)CD11c(+)B220(+)) efficiently endocytose dextran and produce significant levels of tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-12 p40 in response to Toll-like receptor (TLR) ligands, with responses higher than splenic DCs. There is also a differential capability of hepatic DCs to respond to innate signals. Indeed, CD11c(+) hepatic DCs have a greater capacity to respond to innate stimulation but are less capable of inducing CpG activated-allogeneic T cells. These data suggest that hepatic dendritic cells function as a critical bridge between innate and adaptive immunity and are capable of inducing stronger innate responses with a lower capacity for allo-stimulation than splenic dendritic cells. These properties of liver dendritic cells contribute to their unique role in the induction of tolerance.

The role of CD11c(+) hepatic dendritic cells in the induction of innate immune responses

The role of the liver in the initiation and maintenance of tolerance is a critical immune function that involves multiple lineages of immune cells. Included within these populations are liver dendritic cells (DCs). Although there has been significant work on the phenotypic and functional roles of splenic and bone marrow dendritic cells, as well as their subsets, comparable studies in liver have often been difficult. To address this issue we have isolated, from C57BL/6 mice, relatively pure populations of DCs and compared phenotype and function to the data from spleen using flow cytometry, cell sorter assisted purification and culture, morphology by cytospin and May-Giemsa staining, cell cycle progression, antigen uptake, cytokine production and allo-activation potential. natural killer (NK)1.1(-)CD11c(+) liver DC subsets (conventional DCs, T cell receptor (TcR)beta(-)NK1.1(-)CD11c(+)B220(-) and plasmacytoid DCs, TcRbeta(-)NK1.1(-)CD11c(+)B220(+)) efficiently endocytose dextran and produce significant levels of tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-12 p40 in response to Toll-like receptor (TLR) ligands, with responses higher than splenic DCs. There is also a differential capability of hepatic DCs to respond to innate signals. Indeed, CD11c(+) hepatic DCs have a greater capacity to respond to innate stimulation but are less capable of inducing CpG activated-allogeneic T cells. These data suggest that hepatic dendritic cells function as a critical bridge between innate and adaptive immunity and are capable of inducing stronger innate responses with a lower capacity for allo-stimulation than splenic dendritic cells. These properties of liver dendritic cells contribute to their unique role in the induction of tolerance.

Simian immunodeficiency virus (SIV) infection influences the level and function of regulatory T cells in SIV-infected rhesus macaques but not SIV-infected sooty mangabeys

Differences in clinical outcome of simian immunodeficiency virus (SIV) infection in disease-resistant African sooty mangabeys (SM) and disease-susceptible Asian rhesus macaques (RM) prompted us to examine the role of regulatory T cells (Tregs) in these two animal models. Results from a cross-sectional study revealed maintenance of the frequency and absolute number of peripheral Tregs in chronically SIV-infected SM while a significant loss occurred in chronically SIV-infected RM compared to uninfected animals. A longitudinal study of experimentally SIV-infected animals revealed a transient increase in the frequency of Tregs from baseline values following acute infection in RM, but no change in the frequency of Tregs occurred in SM during this period. Further examination revealed a strong correlation between plasma viral load (VL) and the level of Tregs in SIV-infected RM but not SM. A correlation was also noted in SIV-infected RM that control VL spontaneously or in response to antiretroviral chemotherapy. In addition, immunofluorescent cell count assays showed that while Treg-depleted peripheral blood mononuclear cells from RM led to a significant enhancement of CD4+ and CD8+ T-cell responses to select pools of SIV peptides, there was no detectable T-cell response to the same pool of SIV peptides in Treg-depleted cells from SIV-infected SM. Our data collectively suggest that while Tregs do appear to play a role in the control of viremia and the magnitude of the SIV-specific immune response in RM, their role in disease resistance in SM remains unclear.

Expression of PD1 Differs on T Cells from a Pathogenic Versus Nonpathogenic Primate Models of AIDS (43.50)

In most chronic infections antigen specific memory T cells experience a progressive immune exhaustion. Recent reports of HIV infection demonstrate increased expression of PD1 on exhausted T cells correlating with viral loads, and in vitro restoration of function by blockade of PD1 interactions with its ligands. We characterized PD1 in a rhesus macaque model of SIV infection where AIDS develops versus an asymptomatic natural host, sooty mangabeys. Infected animals of both species showed an increase in frequency of total PD1+ CD4+ cells, but not CD8+, which correlated with viral loads in macaques, but not in mangabeys. Furthermore this increase was noted in naïve mangabey CD4+ cells, but central memory macaque CD4+ cells. In macaques, antigen specific CD8+ T cells had increased PD1 expression (MFI) that was reduced with antiviral therapy. While the blockade of PD1-PDL1 interactions in vitro enhanced overall SIV antigen specific responses, individual responses to specific peptides were found enhanced, unchanged or even diminished. These data support a potential for role PD1 in the phenomena of “immune exhaustion” and a rationale for its study using monkey models of AIDS.

Unrecognized peripartum cardiomyopathy in Haitian women

OBJECTIVE

Haitian women have a high relative incidence of clinical presentation with peripartum cardiomyopathy (PPCM): an incidence estimated at one case per three hundred live births, a ten-fold occurrence compared to American women. Our objective has been to test the hypothesis that some Haitian women may have a forme fruste of PPCM while still without clinical symptoms.

METHOD

A preliminary case-control study was conducted at the Hospital Albert Schweitzer (HAS), Deschapelles, Haiti, in which 25 apparently healthy postpartum women, without cardiovascular symptoms and with a normal cardiovascular clinical examination, were selected from a consecutive list of obstetrical deliveries and screened by echocardiography for left ventricular dysfunction.

RESULT

Four out of 25 patients (16%) had asymptomatic left ventricular dysfunction that subsequently evolved towards either improvement or deterioration. Supporting evidence for the existence of asymptomatic left ventricular dysfunction or forme fruste PPCM is presented. A hypothetical schema of the pathophysiology of PPCM explains how a latent phase of variable duration may exist prior to onset of detectable clinical heart failure.

CONCLUSION

Screening Haitian women during the last month of pregnancy or in the early postpartum period may help to detect asymptomatic left ventricular dysfunction. Early detection and treatment of PPCM in a known high risk population could lead to improvements in maternal and fetal mortality and morbidity.

IL-15 is superior to IL-2 in the generation of long-lived antigen specific memory CD4 and CD8 T cells in rhesus macaques

Using tetanus toxoid (TT) and influenza (Flu) immunization of rhesus macaques as a model, the effect of IL-2 and IL-15 on the generation and maintenance of antigen specific memory T cells was evaluated following primary and secondary immunization. Daily cytokine administration expanded primarily effector but not memory cells, while spacing cytokine administration to q3-7 days markedly enhanced TT and Flu specific memory responses. Following primary immunization, TT specific CD4 and influenza matrix protein (Flu-MP) specific CD8 effector responses were enhanced by IL-2 administration but CD8 specific memory responses were no different from cytokine non-treated monkeys. In contrast, expansion of Flu specific CD8 cells with IL-15 was only modest but resulted in significantly elevated levels of memory cells at 6 months. IL-15 also significantly enhanced early and late TT specific CD4 responses. The highest levels of primary effector and memory T cells were observed following alternate administration of both IL-2 and IL-15. Following booster immunization, however, only IL-15 appeared able to enhance CD8 T cell responses while IL-2 or IL2/IL-15 administration were less effective.

An evaluation of strength of composite resin restorations using different bonding agents--an in-vitro study

In the recent years, the scope of conservative dentistry with emphasis on esthetics has increased by leaps and bounds in enhancing individual personality. Composite resins are important for aesthetic restorations in dentistry, specifically in operative dentistry. But without bonding agents the success of composite restorations is minimized. Researchers are constantly endeavoring to improve the quality of bonding agents. The advent of new bonding systems which are capable of bonding both enamel & dentin has opened new avenues in the field of restorative dentistry. With the market floating with new bonding agents claiming superior bonding properties, this study was undertaken to investigate the degree of bond strength produced by three commercially available bonding agents (Syntac, Scotchbond 1, & Clearfil SE) with composite resin (Esthet-X) taken for the experimental procedure.

Optical absorption and NMR spectroscopic studies on paramagnetic trivalent lanthanide complexes with 2,2'-bipyridine.; The solvent effect on 4f-4f hypersensitive transitions

The optical absorption and NMR studies of trivalent lanthanide chloride complexes with 2,2'-bipyridine (bpy) are presented and discussed. The NMR spectra of paramagnetic complexes exhibit lower as well as higher field shifts of bpy resonances that reflect change in geometry and reveals importance of the factor (3 cos2 theta - 1 ) in changing sign of the shift. The paramagnetic shifts recorded have been analyzed and the intramolecular shift ratios suggest that the paramagnetic shift is predominantly dipolar in origin. Electronic spectral studies of the Pr, Nd, Ho, Er and Dy complexes in different solvents (viz. methanol, pyridine, DMSO and DMF), which differ with respect to donor atoms, reveal that the chemical environment around the lanthanide ion has great impact on f-f transitions and any change in the environment results in modifications of the spectra. The oscillator strength for the hypersensitive and non-hypersensitive transitions have been determined and changes in the oscillator strength and band shape with respect to solvent type is rationalized in terms of ligand (solvent) structure and coordination properties.

Norepinephrine enhances adhesion of HIV-1-infected leukocytes to cardiac microvascular endothelial cells

Recent reports have indicated that norepinephrine (NE) enhances HIV replication in infected monocytes and promotes increased expression of select matrix metalloproteinases associated with dilated cardiomyopathy (DCM) in vitro in co-cultures of HIV-infected leukocytes and human cardiac microvascular endothelial cells (HMVEC-C). The influence of NE on HIV infection and leukocyte-endothelial interactions suggests a pathogenic role in AIDS-related cardiovascular disease. This study examined the effects of norepinephrine (NE) and HIV-1 infection on leukocyte adhesion to HMVEC-C. Both flow and static conditions were examined and the expression of selected adhesion molecules and cytokines were monitored in parallel. NE pretreatment resulted in a detectable, dose-dependent increase of leukocyte-endothelial adhesion (LEA) with both HIV-1-infected and -uninfected peripheral blood mononuclear cells (PBMCs) relative to media controls after 48 hr in co-culture with HMVEC-C in vitro. However, the combination of NE plus HIV infection resulted in a significant (P < 0.0001) 18-fold increase in LEA over uninfected media controls. Increased levels in both cell-associated and -soluble ICAM-1 and E-Selectin but not VCAM-1 correlated with increased LEA and with HIV-1 infection or NE pretreatment. Blocking antibodies specific for ICAM-1 or E-Selectin inhibited HIV-NE-induced LEA. These data suggest a model in which NE primes HIV-1-infected leukocytes for enhanced adhesion and localization in HMVEC-C where they can initiate and participate in vascular injury associated with AIDS-related cardiomyopathy.

Protection by SIV VLP DNA prime/protein boost following mucosal SIV challenge is markedly enhanced by IL-12/GM-CSF co-administration

The ever increasing number of people infected by human immunodeficiency virus (HIV) throughout the world renders the development of effective vaccines an urgent priority. Herein, we report on an attempt to induce and enhance antiviral responses using a deoxyribonucleic acid (DNA) prime/virus-like particles (VLP) protein boost strategy adjuvanted with interleukin (IL)-12/GM-CSF in rhesus macaques challenged with simian immunodeficiency virus (SIV). Thus, groups of monkeys were administered three consecutive doses of pVecB7 a plasmid expressing VLP with or without plasmids expressing IL-12 and GM-CSF at weeks 0, 13 and 26. The VLP boost was administered at week 39 with or without IL-12. All monkeys were challenged intrarectally with SIVsmE660 2 months following the protein boost. All except one immunized monkey became infected. While all immunized monkeys showed a marked reduction of acute viral peaks, reduction of viral load set points was only achieved in groups whose prime-boost immunizations were supplemented with IL-12/GM-CSF (prime) and/or with IL-12 (boost). Control of viremia correlated with lack of disease progression and survival. Detection of virus in rectal washes at 1 year post-challenge was only successful in monkeys whose immunizations did not include cytokine adjuvant, but these loads did not correlate with plasma viral loads. In summary, use of IL-12 and/or GM-CSF was shown to provide significant differences in the outcome of SIV challenge of prime/boost immunized monkeys.

Effects of morphine on T-cell recirculation in rhesus monkeys

A 2-yr study on effects of morphine on lymphocyte circulation in rhesus monkeys (Macaca mulatta) showed that, over time, a well-maintained morphine-dependency caused biphasic depressive effects on circulating lymphocyte levels. Depression of T cell circulation by opiates actually was a relative effect. Morphine exposure basically stabilized T cell circulation in the context of concurrent increases in controls. Biphasic effects of morphine were attributable to distinctions in circulation kinetics of CD4+/CD62L (+ & -) T cells. That is, levels of CD4+/CD62L+ T cells were selectively depressed by opiates through the first 32wk after initiation of drug, and levels of CD4+/CD62L- T cells were selectively depressed thereafter. Regression analyses also showed that morphine stabilized lymphocyte recirculation. Circulating levels of resting and activated-memory types of T cells were positively correlated in opiate-exposed monkeys during the first 32wk after opiate exposure--an effect not seen with control monkeys. Considerations of changes in the types of experimental stressors extant during the study suggested that temporally differential effects of opiates on T cell recirculation were connected with changes in the stress environment and the ability of morphine to modulate these changes. Thus, morphine, and by inference the endogenous opioid system, are involved in homeostasis of lymphocyte recirculation, probably through effects on central mediation of the stress axis.

Experimental infection of Macaca nemestrina with a Toronto Norwalk-like virus of epidemic viral gastroenteritis

Norwalk virus (NV) and Norwalk-like viruses (NLVs) are common etiologic agents of viral gastroenteritis. Viral gastroenteritis is a common disease that is highly transmissible, spreading rapidly through families, institutions, and communities. Because methods for in vitro cultivation of Norwalk etiologic agents are not available, information regarding this syndrome has come largely from studies in human volunteers. Sequential passaging of an NLV through an immunoincompetent newborn pigtail macaque (Macaca nemestrina) may allow for the adaptation of a human NLV to a primate host, thus providing an animal model for investigating this disease. A fecal filtrate of human origin containing NLV, Toronto virus P2-A, was obtained from a patient during an epidemic of viral gastroenteritis. The filtrate was administered via nasogastric tube to three newborn pigtailed macaques. Clinical illness, which was characterized by diarrhea, dehydration, and vomiting, occurred in three monkeys. Reverse transcription-polymerase chain reaction (RT-PCR) and oligonucleotide probe analysis of RNA extracted from the stool samples following infection revealed viral RNA in all inoculated monkeys. Infection was also transmitted experimentally by feeding two additional newborn macaques a fecal filtrate prepared from the three previously infected animals. Detection of viral RNA in the stools of animals that received the fecal filtrate indicates that viral replication occurred in association with clinical illness. The susceptibility of Macaca nemestrina to infection with a Norwalk-like agent will facilitate the study of the mechanisms of the pathogenesis of NLV. This system may also have the potential to serve as a vaccine test model for human epidemic viral gastroenteritis.

Administration of recombinant rhesus interleukin-12 during acute simian immunodeficiency virus (SIV) infection leads to decreased viral loads associated with prolonged survival in SIVmac251-infected rhesus macaques

The ability of recombinant rhesus interleukin-12 (rMamu-IL-12) administration during acute simian immunodeficiency virus SIVmac251 infection to influence the quality of the antiviral immune responses was assessed in rhesus macaques. Group I (n = 4) was the virus-only control group. Group II and III received a conditioning regimen of rMamu-IL-12 (10 and 20 microg/kg, respectively, subcutaneously [s.c.]) on days -2 and 0. Thereafter, group II received 2 microg of IL-12 per kg and group III received 10 microg/kg s.c. twice a week for 8 weeks. On day 0 all animals were infected with SIVmac251 intravenously. While all four group I animals and three of four group II animals died by 8 and 10 months post infection (p.i.), all four group III animals remained alive for >20 months p.i. The higher IL-12 dose led to lower plasma viral loads and markedly lower peripheral blood mononuclear cell and lymph node proviral DNA loads. During the acute viremia phase, the high-IL-12-dose monkeys showed an increase in CD3(-) CD8 alpha/alpha(+) and CD3(+) CD8 alpha/alpha(+) cells and, unlike the control and low-IL-12-dose animals, did not demonstrate an increase in CD4(+) CD45RA(+) CD62L(+) naive cells. The high-IL-12-dose animals also demonstrated that both CD8 alpha/alpha(+) and CD8 alpha/beta(+) cells produced antiviral factors early p.i., whereas only CD8 alpha/beta(+) cells retained this function late p.i. Long-term survival correlated with sustained high levels of SIV gag/pol and SIV env cytotoxic T lymphocytes and retention of high memory responses against nominal antigens. This is the first study to demonstrate the capacity of IL-12 to significantly protect macaques from SIV-induced disease, and it provides a useful model to more precisely identify correlates of virus-specific disease-protective responses.

Identification of protein kinases dysregulated in CD4(+) T cells in pathogenic versus apathogenic simian immunodeficiency virus infection

Human immunodeficiency virus infection in humans and simian immunodeficiency virus (SIV) infection in rhesus macaques (RM) leads to a generalized loss of immune responses involving perturbations in T-cell receptor (TCR) signaling. In contrast, naturally SIV-infected sooty mangabeys (SM) remain asymptomatic and retain immune responses despite relatively high viral loads. However, SIV infection in both RM and SM led to similar decreases in TCR-induced Lck phosphorylation. In this study, a protein tyrosine kinase (PTK) differential display method was utilized to characterize the effects of in vivo SIV infection on key signaling molecules of the CD4(+) T-cell signaling pathways. The CD4(+) T cells from SIV-infected RM, but not SIV-infected SM, showed chronic downregulation of baseline expression of MLK3, PRK, and GSK3, and symptomatically SIV-infected RM showed similar downregulation of MKK3. In vitro TCR stimulation with or without CD28 costimulation of CD4(+) T cells did not lead to the enhancement of gene transcription of these PTKs. While the CD4(+) T cells from SIV-infected RM showed a significant increase of the baseline and anti-TCR-mediated ROR2 transcription, SIV infection in SM led to substantially decreased anti-TCR-stimulated ROR2 transcription. TCR stimulation of CD4(+) T cells from SIV-infected RM (but not SIV-infected SM) led to the repression of CaMKKbeta and the induction of gene transcription of MLK2. Studies of the function of these molecules in T-cell signaling may lead to the identification of potential targets for specific intervention, leading to the restoration of T-cell responses.

Effects of norepinephrine, HIV type 1 infection, and leukocyte interactions with endothelial cells on the expression of matrix metalloproteinases

The expression of matrix metalloproteinases (MMPs) associated with AIDS-related cardiomypathies and cocaine abuse was examined in an in vitro coculture model. Human peripheral blood mononuclear cells (PBMCs), HIV infected or uninfected, were placed in coculture with primary human cardiac microvascular endothelial cells (HMVEC-C) in the presence or absence of the cocaine-inducible catecholamine norepinephrine (NE). Culture supernatants were assayed for MMP-1, -2, -3, -7, -9, and -13, and for tissue inhibitor of metalloproteinase 1 (TIMP-1) and TIMP-2, by enzyme-linked immunosorbent assay. Low levels of constitutively expressed MMP-1 and -2 were detected in individual cultures of HMVEC-C and PBMCs. NE did not induce MMP or TIMP expression by HMVEC-C and caused modest increases (3- to 4-fold) in MMP-1 and -2 by uninfected PBMCs. Increased levels of NE-induced MMP-1 (5-fold) and MMP -2 (15-fold) were detected in cocultures of HMVEC-C and uninfected PBMCs. HIV infection enhanced MMP-1 (46-fold) and MMP-2 (48-fold) and active MMP-7 (33-fold) and MMP-9 (50-fold) by PBMCs. Coculture of HIV-infected PBMCs with HMVEC-C increased MMP-1 (110-fold) and MMP-2 (307-fold) but not active MMP-7 and -9. The combination of NE, HIV infection, and coculture increased MMP-1 (126-fold) and MMP-2 (467-fold), and active MMP-7 (65-fold) and MMP-9 (75-fold). MMP-3 or-13 was not detected in any of the treatment groups and TIMP-1 and -2 appeared inversely proportional to the observed levels of MMPs. These results suggest that HIV infection, NE, and leukocyte endothelial interactions demonstrate separate and overlapping cooperative effects on the regulation of expression of TIMPs and MMPs associated with AIDS-related cardiomyopathies.

Immunoglobulin gene usage and immunohistochemical characteristics of human monoclonal antibodies to the mitochondrial autoantigens of primary biliary cirrhosis induced in the XenoMouse

The immunodominant antimitochondrial antibody (AMA) response in primary biliary cirrhosis (PBC) is directed against the E2 component of pyruvate dehydrogenase (PDC-E2). The nature of the clonal selection process is unclear, and to address this issue, we took advantage of a transgenic technology, XenoMouse, that contains 80% of the human immunoglobulin (Ig) variable gene repertoire and can produce high-affinity human antibodies to virtually any immunogen without evidence of clonal bias. We immunized mice with PDC-E2 to obtain 13 HmAbs, including 4 IgG(2) and 9 IgM isotypes. Immunoglobulin gene analysis was unique and demonstrated a clonal bias; the immunoglobulin gene usage was considerably different from other antibody responses analyzed in XenoMouse systems. Four of the 13 mAbs recognized the inner lipoyl domain of PDC-E2, 2 of 13 recognized the entire PDC-E2 molecule, 4 of 13 recognized PDC-E2 and OGDC-E2, 1 of 13 recognized OGDC only, 1 recognized BCOADC-E2 only, and 1 recognized an unidentified 100-kd mitochondrial protein. Immunohistochemical staining using these HmAbs produced mitochondrial staining of septal bile ducts in both PBC and control livers. Ig gene analysis showed that 7 of 13 HmAbs used the V(H)3 and 4 of 13 used VH4 gene repertoire, respectively. Three of 7 V(H)3 antibodies used the same Ig VH3-21 gene family found in human AMA from patients with PBC. The CDRs of these autoantibodies were slightly mutated when compared with the sequences present within the Ig germline genes. In conclusion, the XenoMouse not only recapitulates the unique specificity and restriction of PBC patients, but indicates that the autoantibodies are derived from a restricted clonal selection process. Such data suggest that the original immunogen leads to somatic mutation without subsequent development of determinant spreading.

Chronic immune stimulation accelerates SIV-induced disease progression

The contribution of chronic immune stimulation on the progression of lentivirus-induced disease was evaluated in the SIVmac251 macaque model of AIDS. Following SIV inoculation, seroconversion and control of the acute viral replication phase, repeated immune stimulations with tetanus toxoid (TT), keyhole limpet hemocyanin (KLH) and allogeneic peripheral blood mononuclear cells (PBMC) were initiated in four monkeys. These animals showed a significant shortening of survival when compared with eight non-immune-stimulated control animals inoculated with the same route, dose and stock of SIVmac251 (median survival 9.5 months versus 17 months, P = 0.010). In addition, when the comparison was extended to another 22 control animals of different origin but inoculated by the same route with similar doses and stocks of SIVmac251, the difference in survival was still significant (9.5 versus 18 months, P = 0.003). This accelerated progression of symptomatic disease was not accompanied with significant increases in plasma viral loads, but suboptimal antibody responses to the immunizing antigens were noted, correlating with the length of survival. These findings may have implications for HIV-infected humans suffering from chronic infectious diseases.

Risk of arsenic transfer to a semi-confined aquifer and the effect of water level fluctuation in North Mortagne, France at a former industrial site

Groundwater contamination by arsenic was studied in the area of a former larger zinc refinery in France. Maximum contamination was observed under the former sulfuric acid factory, while the overall waste storage area was less contaminated. Arsenic concentrations there were controlled by the solubility of 3:2 calcium arsenate mineral Ca3(AsO4)2 (s) and probably a gypsum/calcium arsenate CaSO4 (s)/Ca3(AsO4)2 (s) solid solution. The speciation of As below the former sulfuric acid factory indicates an overall predominance of As(III) species. The sorption by the clay aquitard was complete for As(V), but limited to approximately 30% for As(III) under our experimental conditions. A potential risk exists, although very limited in area, of contamination of the underlying sandy aquifer and drinking water wells.

Genomic analysis of differentially expressed genes in liver and biliary epithelial cells of patients with primary biliary cirrhosis

The characterization of differentially expressed genes provides a powerful tool for identifying molecules that may be involved in the pathogenesis of disease. We have used two independent techniques to identify overexpressed transcripts in bile duct cells and in liver from patients with primary biliary cirrhosis (PBC). In the first method, we used suppressive subtractive hybridization to compare mRNA from isolated PBC bile duct epithelial cells (BECs) to normal BECs and identified 71 clones as transcribed at higher levels in PBC-BECs. Amongst these clones, 62/71 had matches in a non-redundant nucleotide database and 9/71 had matches in an EST database. Of the 62 clones, 51/62 include a complexity of genes involved in cell proliferation, signal transduction, transcription regulation, RNA processing, carbohydrate metabolism and hypothetical/unknown proteins; 4/62 were identified as interstitial collagenase and collagenase precursors, 4/62 as ribosomal proteins, 3/62 as mitochondrial DNA. The mitochondrial cDNA sequences included cytochrome c oxidase, Wnt-13, and the pHL gene, a c-myc oncogene containing coxIII sequence. In the second method, we constructed cDNA libraries from three different PBC livers and sequenced a total of 12,324 independent clones. These 12,324 clones underwent virtual subtraction with 2,814,148 independent clones from Incyte LifeSeq libraries. Twenty one sequences were identified as unique to PBC liver. Collectively, these approaches identified a number of genes involved in signalling, RNA processing, mitochondrial function, inflammation, and fibrosis. Interestingly, both Wnt-13 and Notch transcripts are overexpressed in PBC liver. Further studies are needed to focus on the significance of these genes during the natural history of disease.

Xenobiotic considerations for the development of autoimmune liver diseases: bad genes and bad luck

The etiologic origins of autoimmune disease remain an enigma. Although considerable information on the mechanisms of immunopathology has been acquired, in part from murine models, such mechanisms have yet to be substantiated in human autoimmune disease. This absence of validation is especially true for organ-specific diseases like those affecting the liver. In this review we focus on the putative role of xenobiotics as inducing agents for autoimmune liver pathology. In particular, we discuss the autoantibody immune response, the humoral hallmark of autoimmune disease, as well as cellular immune responses. We believe that exposure to environmental factors, namely xenobiotics, is the initiating straw that breaks the camel's back, leading to the loss of tolerance to self proteins in genetically susceptible hosts. The end result is a perpetuating process that is determined by the governing features of the genetics of the host and by exposure to the inciting environmental agent. Interestingly, the liver, an organ that plays a major role in immune tolerance, can itself become the target of autoreactivity and immune destruction.

Hantavirus infection induces the expression of RANTES and IP-10 without causing increased permeability in human lung microvascular endothelial cells

Sin Nombre virus (SNV) and Hantaan virus (HTN) infect endothelial cells and are associated with different patterns of increased vascular permeability during human disease. It is thought that such patterns of increased vascular permeability are a consequence of endothelial activation and subsequent dysfunction mediated by differential immune responses to hantavirus infection. In this study, the ability of hantavirus to directly induce activation of human lung microvascular endothelial cells (HMVEC-Ls) was examined. No virus-specific modulation in the constitutive or cytokine-induced expression of cellular adhesion molecules (CD40, CD54, CD61, CD62E, CD62P, CD106, and major histocompatibility complex classes I and II) or in cytokines and chemokines (eotaxin, tumor necrosis factor alpha, interleukin 1beta [IL-1beta], IL-6, IL-8, MCP-1, MIP-1alpha, and MIP-1beta) was detected at either the protein or message level in hantavirus-infected HMVEC-Ls. Furthermore, no virus-specific enhancement of paracellular or transcellular permeability or changes in the organization and distribution of endothelial intercellular junctional proteins was observed. However, infection with either HTN or SNV resulted in detectable levels of the chemokines RANTES and IP-10 (the 10-kDa interferon-inducible protein) in HMVEC-Ls within 72 h and was associated with nuclear translocation of interferon regulatory factor 3 (IRF-3) and IRF-7. Gamma interferon (IFN-gamma)-induced expression of RANTES and IP-10 could also be detected in uninfected HMVEC-Ls and was associated with nuclear translocation of IRF-1 and IRF-3. Treatment of hantavirus-infected HMVEC-Ls with IFN-gamma for 24 h resulted in a synergistic enhancement in the expression of both RANTES and IP-10 and was associated with nuclear translocation of IRF-1, IRF-3, IRF-7, and NF-kappaB p65. These results reveal a possible mechanism by which hantavirus infection and a TH1 immune response can cooperate to synergistically enhance chemokine expression by HMVEC-Ls and trigger immune-mediated increases in vascular permeability.

Failure to expand influenza and tetanus toxoid memory T cells in vitro correlates with disease course in SIV infected rhesus macaques

Marked decreases in influenza (flu) and tetanus toxoid (T.T.) antigen specific CD8(+) and CD4(+) T cell memory responses were noted shortly after SIV infection in monkeys that go on to develop clinical disease within 18 months (normal progressor, NP) following SIV infection but not in monkeys that remain asymptomatic >3 years post SIV infection (long-term nonprogressor, LTNP). While PBMCs from NP and LTNP monkeys demonstrate both low and high avidity flu and T.T. specific CD8(+) and CD4(+)T cell immune responses prior to SIV infection, the PBMCs from NP but not LTNP fail to generate high avidity T cell responses post SIV infection. This failure to generate high avidity T cell responses in vitro correlated with increased apoptotic cell death in PBMC cultures from NP animals. Since high avidity antigen specific CTLs have been shown to be most efficient in eliminating viral infections, the present finding has important implications for the evaluation of the level of immune reconstitution following various modalities of therapy in HIV-1 infected patients.

B cells are selectively associated with thymic cortical but not medullary pathology in NZB mice

Abnormal expansion of autoantibody-synthesizing B cells and self-reactive T cells, which most likely escape negative selection within the thymus, have both been characterized and reasoned to play a role in the pathogenesis of autoimmunity in NZB mice. Support for this thesis has been our observation that NZB mice have severe cortical and medullary thymic microarchitectural defects. As a means to dissect the roles of T and B cells in the induction of such abnormalities, B cell-deficient NZB mice were bred by backcrossing the Igh6(null)allele on to the NZB background (NZB-muMT mice). Such mice showed undetectable levels of autoantibodies. NZB-muMT mice, as compared to wild-type NZB mice, had lower absolute numbers of CD4(+)T cells. Furthermore, thymic abnormalities in NZB-muMT mice were restricted to the medulla. These data suggest that, while B cells may play a role in thymic cortical abnormalities, the medullary abnormalities are induced by other mechanisms.

Cloning, sequencing, and homology analysis of nonhuman primate Fas/Fas-ligand and co-stimulatory molecules

The finding that a single administration of select recombinant human cytokines to nonhuman primates leads to potent cytokine-neutralizing antibody responses in the heterologous host despite >95% homology at the nucleotide and protein level prompted our laboratory to clone, sequence, and prepare recombinant nonhuman primate cytokines, chemokines, growth factors, and other immunoregulatory molecules. In the present report, we present findings on the gene sequences encoding the nonhuman primate homologues of human CD80, CD86, their ligands CD28 and CD152, CD154, CD95, and CD95-L from rhesus macaques and for phylogenetic analysis from pig-tailed macaques, African sooty mangabey monkeys, baboons, and vervets as well as select molecules from the New World aotus and marmoset monkeys. With the exception of CD95, the homology between nonhuman primate and human co-stimulatory molecules was above 95%. In contrast, CD95 was only 89.2% homologous to human CD95, but the differences were essentially found in the transmembrane and intracellular (death) domains. The extracellular portion of CD95 was more homologous which was in accordance with approximately 98% homology between Old World monkey and human CD95-L. In general, sequences from the New World monkey species appeared equidistant to sequences from Old World species and humans in terms of homology suggesting distinct evolutionary patterns. Of interest was the isolation of various splice variants of monkey CD86, CD152 (CTLA-4), CD154, and CD95 transcripts. This is also the first report documenting the occurrence of natural CD86 variants with deleted transmembrane domains, found both in sooty mangabeys and baboon RNA samples. Monkey CD95 showed various deletions and addition of residues in the transmembrane and intracytoplasmic domains compared with human CD95 and between Old and New World species. Subcloning of rhesus CD154 into an expression vector demonstrated expression of a functional protein in cell culture. The other genes are being cloned into expression vectors for the preparation and biological characterization of the nonhuman primate molecules. These investigations will provide novel reagents for in vivo use as immunomodulatory reagents in nonhuman primates in studies which may provide a rationale for their use in humans.