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.

Porcine aortic endothelial cells transfected with HLA-G are partially protected from xenogeneic human NK cytotoxicity.

In this study we tested whether the expression of HLA-G protects porcine endothelial cells (PEC) from the lysis mediated by human natural killer (NK) cells. Because HLA-E is not present in PEC, this model provides an ideal tool to study the direct role of HLA-G in NK inhibition. Immortalized porcine aortic endothelial cells (PED) were stably transfected with a vector coding for the HLA-G1 protein and surface expression was demonstrated by flow cytometry analysis.

[Ant venoms: a rare cause of allergic reactions in Switzerland].

In Switzerland, unlike other countries, allergic reactions to ants are a rare phenomenon when compared to the well known allergies to bee and wasp venom. In this report we present a series of case reports and a review of the different types of allergy to ants. Due to increased travel and heterogeneity of the population, we have observed several patients with sensitisation or allergy to the venom of imported fire ants (Solenopsis), a species of ant found in the Americas.

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.

Age-related expression of the cellular prion protein in human peripheral blood leukocytes.

Background And Objective: Creutzfeldt-Jakob disease typically affects older patients, yet victims of new-variant Creutzfeldt-Jakob disease (nvCJD) are unusually young. Because the cellular prion protein PrP(C) is required for disease development, we investigated age-dependent variability in cell surface PrP(C) expression on various subclasses of human peripheral blood leukocytes (PBL) as a possible susceptibility factor.

Design And Methods: Three age groups of healthy individuals (mean ages: 6, 33 and 68) were studied by two-color FACS analysis of PBL with fluorescent monoclonal antibodies to PrP(C) and to the lineage markers CD3, CD19, CD4, and CD8.

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.

[Mechanisms of xenotransplant rejection].

The recent shortage of allogeneic human organs in transplantation medicine has led to a renewed interest in evaluating the feasibility of xenotransplantation, particularly of porcine origin. Discordant xenotransplants between phylogenetically distant species such as pig and primates are challenged by a series of strong rejection reactions. Hyperacute rejection is dominantly mediated by humoral responses of the immune system (natural antibodies, complement cascade) and the activation of coagulation factors, whereas delayed xenograft rejection and T-cell mediated responses are also mediated by elements of the cellular immune system.

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.

Human CD4+ T cells mediate rejection of porcine xenografts.

It has previously been demonstrated that xenograft rejection in rodents is dependent on CD4+ T cells. However, because of the lack of an appropriate in vivo model, little is known about the cellular basis of human T cell-mediated rejection of xenografts. In this study, we have evaluated the ability of human T cells to mediate rejection of porcine skin grafts in a novel in vivo experimental system using immunodeficient mice as recipients.

Cross-species interaction of porcine and human integrins with their respective ligands: implications for xenogeneic tolerance induction.

Background: Organ transplantation is limited by the number of available donors. One possible solution would be the use of pigs as organ donors. However, current immunosuppressive protocols cannot prevent rejection of these organs.

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.

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.

Species differences in the expression of major histocompatibility complex class II antigens on coronary artery endothelium: implications for cell-mediated xenoreactivity.

Background: There is controversy in the literature as to whether swine coronary endothelium expresses major histocompatibility complex (MHC) class II antigens constitutively.

Methods: Because this issue has implications for cell-mediated human anti-swine xenogeneic responses, we stained tissue sections from human, pig, rat, and mouse hearts with the anti-class II monoclonal antibody ISCR3, which has a similar specificity and titer when binding to human, porcine, and rodent class II molecules.

Results: Immunoperoxidase staining of human and porcine hearts with ISCR3 resulted in a dense reaction on the coronary endothelium of epicardial arteries, intramuscular arterioles, and capillaries.

HLA-Cw3 expression on porcine endothelial cells protects against xenogeneic cytotoxicity mediated by a subset of human NK cells.

There is increasing evidence that NK cells make an important contribution to human anti-porcine xenogeneic cytotoxicity. Most allogeneic as well as autologous normal cells are not susceptible to NK cell-mediated cytotoxicity because they express inhibitory molecules encoded within the MHC class I loci. The protective signal is delivered to NK cells through killer cell-inhibitory receptors expressing different MHC class I specificities.

Human cell-mediated rejection of porcine xenografts in an immunodeficient mouse model.

Background: In this study, we describe the development of a novel experimental system in which rejection of porcine skin grafts by human peripheral blood cells can be studied directly in vivo in immunodeficient mice.

Methods: To construct a small animal model of discordant xenograft rejection, recombinase-activating gene-deficient mice (R-) lacking both mature B and T cells were grafted with porcine skin grafts and administered, by adoptive cell transfer, human cells stimulated in vitro with irradiated porcine peripheral blood cells to create Hu-R- mice.

Results: R- mice accepted porcine skin grafts indefinitely without the need for immunosuppression.

The diagnostic value of the neutrophil left shift in predicting inflammatory and infectious disease.

The use of neutrophil left-shift parameters in the diagnosis of inflammatory and infective disease (ID) was evaluated. The level of C-reactive protein (CRP), currently the best quantitative parameter of inflammation, was used as the gold standard. Of 292 patients, 230 (79%) had a level of CRP of 1.

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.

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.

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.

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.