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J Seebach

Publications and source records attributed to J Seebach.

18 recordsLinked to original sources
PubMed2001

Overview of the Third International Workshop on Swine Leukocyte Differentiation Antigens.

The aim of the Third International Workshop on Swine Leukocyte Differentiation Antigens (CD workshop), supported by the Veterinary Immunology Committee (VIC) of the International Union of Immunological Societies (IUIS), was to standardize the assignment of monoclonal antibodies (mAb) reactive with porcine leukocyte differentiation antigens and to define new antibody clusters, using nomenclature in accordance with human and ruminant CD nomenclature, as agreed at the summary meeting of the Second International Swine CD Workshop in Davis, 1995: only mAb with proven reactivity for the orthologous porcine gene product or cross-reactivity for the human gene products, were given the full CD nomenclature, all other allocations were prefixed with "w". As in previous workshops, the overall organization was entrusted to the chair and first author, with support by the chair of the previous workshop and second author. In addition to the existing 26 pig leukocyte CD/SWC determinants established in previous workshops, this workshop established/confirmed another 11 CDs for pig leukocytes, identified by a total of 21 mAb: CD11R1 (2 mAb), CD11R2 (1 mAb), CD11R3 (4 mAb), wCD40 (1 mAb), wCD46 (4 mAb), wCD47 (3 mAb), wCD49d (1 mAb), CD61 (1 mAb), wCD92 (1 mAb), wCD93 (1 mAb) and CD163 (2 mAb).

Animals↗
PubMed2001

Summary of the first round analyses of the Third International Workshop on Swine Leukocyte Differentiation Antigens.

The reactivity of 155 monoclonal antibodies submitted to the Third International Workshop on Swine Leukocyte Differentiation Antigens, together with 41 internal standards, was analysed by flow cytometry on 29 different pig cell targets as well as two human cell targets as a means of establishing suitable panels of monoclonal antibodies for more detailed clustering analyses by the various subsections of the workshop. Results were collected either without further gating, with gating based on FS/SS characteristics or with gating based on the co-expression of a reference antibody in two-colour flow cytometry. The CD or SWC reactivity of the internal standards had been established in previous workshops. Data sets were subsequently analysed by statistical clustering using the Leucocyte Typing Database IV software. The resulting 18 cluster groups were allocated to the appropriate second round sections of the workshop, after reviewing the overall cellular reactivity of each cluster as well as the specificity of known standards which clustered in a group.

Animals↗
PubMed2000

Impaired CTL recognition of cells latently infected with Kaposi's sarcoma-associated herpes virus.

Kaposi's sarcoma-associated herpes virus (KSHV) is a recently identified human gamma2-herpesvirus associated with Kaposi's sarcoma, primary effusion lymphoma, and Castleman's disease. We reasoned that CTL responses may provide host defense against this virus, and consequently, KSHV may have evolved strategies to evade the CTL-mediated immune surveillance. In this study six B cell lines latently infected with KSHV were found to express reduced levels of HLA class I surface molecules compared with B cell lines transformed by the related gamma-herpesvirus EBV. KSHV-infected cells also required higher concentrations of soluble peptides to induce efficient CTL-mediated lysis than control cell lines and were unable to process and/or present intracellularly expressed Ag. Incubation of the KSHV-infected cell lines with high concentrations of soluble HLA class I binding peptides did not restore the deficient HLA class I surface expression. To assess the underlying mechanisms of these phenomena, TAP-1 and TAP-2 gene expression was analyzed. While no attenuation in TAP-2 expression was observed, TAP-1 expression was significantly reduced in all KSHV cell lines compared with that in controls. These results indicate that KSHV can modulate HLA class I-restricted Ag presentation to CTL, which may allow latently infected cells to escape CTL recognition and persist in the infected host.

Antigen Presentation↗
PubMed2000

Analysis of the composite response of shear wave resonators to the attachment of mammalian cells.

The suitability of the quartz crystal microbalance (QCM) technique for monitoring the attachment and spreading of mammalian cells has recently been established. Different cell species were shown to generate an individual response of the QCM when they make contact with the resonator surface. Little is known, however, about the underlying mechanisms that determine the QCM signal for a particular cell type. Here we describe our results for different experimental approaches designed to probe the particular contributions of various subcellular compartments to the overall QCM signal. Using AC impedance analysis in a frequency range that closely embraces the resonators' fundamental frequency, we have explored the signal contribution of the extracellular matrix, the actin cytoskeleton, the medium that overlays the cell layer, as well as the liquid compartment that is known to exist between the basal plasma membrane and the culture substrate. Results indicate that the QCM technique is only sensitive to those parts of the cellular body that are involved in cell substrate adhesion and are therefore close to the resonator surface. Because of its noninvasive nature, sensitivity, and time resolution, the QCM is a powerful means of quantitatively studying various aspects of cell-substrate interactions.

3T3 Cells↗
PubMed2000

Endothelial barrier function under laminar fluid shear stress.

It has been suggested that increasing levels of shear stress could modify endothelial permeability. This might be critical in venous grafting and in the pathogenesis of certain vascular diseases. We present a novel setup based on impedance spectroscopy that allows online investigation of the transendothelial electrical resistance (TER) under pure laminar shear stress. Shear stress-induced change in TER was associated with changes in cell motility and cell shape as a function of time (morphodynamics) and accompanied by a reorganization of catenins that regulate endothelial adherens junctions. Confluent cultures of porcine pulmonary trunk endothelial cells typically displayed a TER between 6 and 15 ohms cm2 under both resting conditions and low shear stress levels (0.5 dyn/cm2). Raising shear stress to the range of 2 to 50 dyn/cm2 caused a transient 2% to 15% increase in TER within 15 minutes that was accompanied by a reduction in cell motility. Subsequently, TER slowly decreased to a minimum of 20% below the starting value. During this period, acceleration of shape change occurred. In the ensuing period, TER values recovered, reaching control levels within hours and associated with an entire deceleration of shape change. A heterogeneous distribution of alpha-, beta-, and gamma-catenin, main components of the endothelial adherens type junctions, was also observed, indicating a differentiated regulation of shear stress-induced junction rearrangement. Additionally, catenins were partly colocalized with beta-actin at the plasma membrane, indicating migration activity of these subcellular parts. Shear stress, even at peak levels of 50 dyn/cm2, did not cause intercellular gap formation. These data show that endothelial monolayers exposed to increased levels of laminar shear stress respond with a shear stress-dependent regulation of permeability and a reorganization of junction-associated proteins, whereas monolayer integrity remains unaffected.

Animals↗
PubMed1999

An allelic non-histocompatibility antigen with wide tissue distribution as a marker for chimerism in pigs.

It is frequently useful in studies of transplantation to have available an antibody to a cell surface antigen, which is not itself responsible for transplant rejection. In this paper, we identify and describe such an antibody/antigen system in miniature swine. The monoclonal antibody, 1038H-10-9, was found to react to a pig allelic antigen (called PAA), found on a variety of pig cells and tissues, including peripheral blood mononuclear cells (PBMC), thymocytes, lymph node, bone marrow, and skin. Analysis for recipient sensitization against PAA was performed by in vitro cell-mediated lympholysis (CML) assay, mixed lymphocyte reaction (MLR) assay, antibody binding studies, and skin graft rejection patterns were examined. No evidence was found to indicate detection of PAA by any of these assays of alloreactivity. We therefore conclude that PAA is an allelic swine cell surface antigen, with wide tissue distribution, and that it is not a histocompatibility antigen. It should provide a powerful tool for studies of transplantation biology in miniature swine, such as identification and quantification of chimerism following organ transplantation.

Animals↗
PubMed1998

Trophoblast class I major histocompatibility complex (MHC) products are resistant to rapid degradation imposed by the human cytomegalovirus (HCMV) gene products US2 and US11.

US11 and US2 encode gene products expressed early in the replicative cycle of human cytomegalovirus (HCMV), which cause dislocation of human and murine major histocompatibility complex (MHC) class I molecules from the lumen of the endoplasmic reticulum to the cytosol, where the class I heavy chains are rapidly degraded. Human histocompatibility leukocyte antigens (HLA)-C and HLA-G are uniquely resistant to the effects of both US11 and US2 in a human trophoblast cell line as well as in porcine endothelial cells stably transfected with human class I genes. Dislocation and degradation of MHC class I heavy chains do not appear to involve cell type-specific factors, as US11 and US2 are fully active in this xenogeneic model. Importantly, trophoblasts HLA-G and HLA-C possess unique characteristics that allow their escape from HCMV-associated MHC class I degradation. Trophoblast class I molecules could serve not only to block recognition by natural killer cells, but also to guide virus-specific HLA-C- and possibly HLA-G-restricted cytotoxic T-lymphocytes to their targets.

Animals↗
PubMed1998

Chemokines and chemotaxis of leukocytes in infectious meningitis.

Chemokines constitute a constantly growing family of small inflammatory cytokines. They have been implied in many different diseases of the CNS including trauma, stroke and inflammation, e.g., multiple sclerosis. In this review we focus on the role of chemokines in infectious meningitis of bacterial or viral origin. In experimental bacterial meningitis induced by Listeria monocytogeneses both CXC and CC chemokines namely MIP-1alpha, MIP-1beta and MIP-2 are produced intrathecally by meningeal macrophages and leukocytes which infiltrate into the CNS. In patients with bacterial meningitis, IL-8, GROalpha, MCP-1, MIP-1alpha and MIP-1beta are detectable in the CSF. These chemokines contribute to CSF mediated chemotaxis on neutrophils and PBMC in vitro. In viral meningitis IL-8, IP-10 and MCP-1 are identified in the CSF to be responsible for chemotactic activity on neutrophils, PBMC and activated T cells. Taken collectively these data indicate that the recruitment of leukocytes in infectious meningitis involves the intrathecal production of chemokines.

Chemokines↗
PubMed1997

C-X-C and C-C chemokines are expressed in the cerebrospinal fluid in bacterial meningitis and mediate chemotactic activity on peripheral blood-derived polymorphonuclear and mononuclear cells in vitro.

The appearance of polymorphonuclear and mononuclear leukocytes in the cerebrospinal fluid (csf) is an important hallmark of bacterial meningitis. Chemokines are candidate mediators of cell migration from blood into the subarachnoid space. Therefore, concentrations of C-X-C and C-C chemokines in the csf of patients with pyogenic meningitis were measured by ELISA. Highly significant elevations of chemokine levels in comparison with noninflammatory csf controls were found for IL-8 (median, 21.6 ng/ml; range, < 0.1 to 191.3), growth-related gene product alpha (median, 5.6 ng/ml; range, < 0.1 to 48.2), monocyte chemotactic protein-1 (median, 26.4 ng/ml; range, < 0.2 to 193.8), macrophage inflammatory protein-1 alpha (MIP-1 alpha; median, 1.8 ng/ml; range, < 0.5 to 18.0), MIP-1 beta (median, 10.6 ng/ml; range, < 0.3 to 84.4), but not for RANTES (regulated upon activation, normal T cell expressed and secreted). The csf of bacterial meningitis were chemotactic for neutrophils and mononuclear leukocytes. Correlation analysis demonstrated a strong association between individual chemokine levels and chemotactic activity mediated by csf. A significant reduction of neutrophil chemotaxis was obtained by anti-IL-8 and anti-growth-related gene product alpha Abs, and a reduction of mononuclear cell migration was achieved by a combination of anti-monocyte chemotactic protein-1, anti-MIP-1 alpha, and anti-MIP-1 beta Abs. Since no significant correlation was found between csf leukocyte counts and chemokine concentrations or chemotactic activity mediated by csf, additional factors influence the extent of pleocytosis in vivo.

Adult↗
PubMed1995

Experimental Listeria meningoencephalitis. Macrophage inflammatory protein-1 alpha and -2 are produced intrathecally and mediate chemotactic activity in cerebrospinal fluid of infected mice.

In bacterial meningitis, the recruitment of leukocytes across the blood-brain barrier into the central nervous system may be crucial for both elimination of pathogens and tissue injury. In addition to bacterial cell wall products, host factors including chemokines may lead to accumulation of phagocytes within the central nervous system. As shown by Northern analysis, brains of mice infected intracerebrally with Listeria monocytogenes (LM) express mRNA for three chemokines, the macrophage inflammatory protein (MIP)-1 alpha, MIP-1 beta, and MIP-2. The cellular sources of these chemokines comprise both the blood-derived polymorphonuclear leukocytes (PMNs) and monocytes infiltrating the meninges, the ventricular system and the periventricular area. In the course of meningitis a time-dependent increase of MIP-1 alpha and MIP-2 was found in the cerebrospinal fluid (CSF) by ELISA. CSF taken 24 h after infection (CSF-LM24) induced migration of human leukocytes when treated in chemotactic chambers in vitro. Neutralizing Abs to chemokines identified MIP-1 alpha and MIP-2 to be responsible for CSF-LM24 mediated chemotaxis of monocytes and PMNs, respectively. CSF obtained from mock-infected animals contained no MIP-1 alpha or MIP-2 and did not lead to migration of leukocytes. When testing CSF-LM24 on mouse spleen cells, the chemotactic activity detected for mononuclear cells was only partly inhibited by Abs to MIP-1 alpha and -1 beta. Thus, in addition to MIP-1 and -2 other not yet defined chemotactic factors are of importance for recruitment of leukocytes in bacterial meningitis.

Animals↗
PubMed1995

GM-CSF-induced acute eosinophilic pneumonia.

There is increasing evidence that haemopoietic growth factors are effective in reversal of neutropenia associated with large granular lymphocytes (LGLs) proliferation. A 19-year-old woman with CD3+/TCR gamma delta+, CD4-, CD8- LGL proliferation and severe neutropenia repeatedly developed blood eosinophilia, fever and dyspnoea after administration of GM-CSF. Acute eosinophilic pneumonia with a lobar lung infiltrate pleural effusion, and marked bronchoalveolar lavage fluid eosinophilia was diagnosed. Treatment with corticosteroids and discontinuation of GM-CSF lead to rapid improvement. In addition, haematological analysis revealed that H*1 Technicon, a widely-used automated cell counter, may misinterpret eosinophils erroneously as neutrophils, therefore examination of blood smears to prevent eosinophil-mediated toxicity during GM-CSF treatment is recommended.

Acute Disease↗
PubMed1995

Epinephrine test and plasma elastase as diagnostic tools in a patient with CD3+ large granular lymphocyte proliferation.

Large granular lymphocytes (LGL) proliferation is characterized by expansion of cytotoxic lymphocytes and associated with neutropenia. In a case of CD3+ LGL-proliferation the epinephrine stimulation test (EST) induced a striking elevation of CD3+, CD8+, CD57+ LGL in peripheral blood from 2.7 x 10(9)/l to 20 x 10(9)/l and might be an additional diagnostic tool in patients with normal or low absolute numbers of circulating LGL. After treatment with steroids, plasma elastase--a marker of neutrophil destruction--decreased from 162 to 40 micrograms/l (normal < 47 micrograms/l) which correlated well with a simultaneous increase in peripheral neutrophil counts from 0.14 to 1.0 x 10(9)/l. This finding supports the hypothesis that neutropenia in CD3+ LGL proliferation is due to neutrophil destruction, possibly mediated by LGL.

Aged↗