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J R Westphal

Publications and source records attributed to J R Westphal.

47 records · Page 3Linked to original sources
PubMed1993

The proliferative response of human T cells to allogeneic IFN-gamma-treated endothelial cells is mediated via both CD2/LFA-3 and LFA-1/ICAM-1 and -2 adhesion pathways.

We studied the proliferative response of purified human peripheral blood T lymphocytes (contaminated with less than 0.1% monocytes) to allogeneic MHC class II molecules expressed by endothelial cells (EC) or fibroblasts (FB). In vitro expression of MHC class II molecules was induced by gamma-interferon (IFN-gamma) treatment. The MHC class II expression levels after IFN-gamma treatment on both cell types were comparable. No T cell proliferation was found in the presence of either untreated or IFN-gamma-treated FB, and a marginal proliferation in the presence of untreated EC. IFN-gamma-treated EC, however, were able to induce significant T cell growth. The previously established role of MHC class II molecules in allogeneic T cell proliferation was confirmed in inhibition experiments with monoclonal antibody (mAb) against MHC class II or CD4. In this model, we tested the involvement of a number of adhesion molecules by adding mAbs to cocultures of T cells and IFN-gamma-treated EC. Monoclonal antibodies directed against CD31, CD26, B7/BB1, E-selectin, CD44, VLA-4 alpha-chain and VCAM-1 had no effect, whereas moderate inhibition was observed with anti-VLA-beta-chain and anti-LFA-3. A distinct inhibition of T cell proliferation was observed with mAbs directed against LFA-1, CD2, or a combination of anti-ICAM-1 and -2. Combinations of mAbs directed against T cell adhesion molecules (LFA-1, CD2, VLA-4) or EC adhesion molecules (ICAM-1, and -2, LFA-3, VCAM-1) were able to block T cell proliferation for 100 and 80% respectively. We conclude that CD2/LFA-3 and LFA-1/ICAM interactions are crucially involved in allogeneic T cell/EC interactions.

Antibodies, Monoclonal↗
PubMed1993

A new 180-kDa dermal endothelial cell activation antigen: in vitro and in situ characteristics.

PN-E2 is a monoclonal antibody generated against recombinant tumor necrosis factor-alpha (TNF-alpha)-treated human umbilical vein endothelial cells (EC). PN-E2 recognized a molecule with expression levels in vitro that could be downregulated by TNF, and in situ PN-E2 showed only weak reactivity with vascular EC in normal skin, as assessed by immunohistochemical staining. The expression of PN-E2 was considerably increased on EC in various pathologic skin lesions, including psoriasis, granulation tissue, and inflamed skin. PN-E2 antigen expression was analyzed in more detail in vitro on cultured EC and fibroblasts by use of enzyme-linked immunosorbent assay and fluorescence-activated cell sorter techniques. The expression level on human umbilical vein endothelial cells and capillary EC was, in contrast to the in situ immunohistologic findings, invariably high. On fibroblasts, a low expression was found. Incubation of the EC with recombinant TNF-alpha decreased expression by a factor of 2. Incubation of EC with recombinant interferon-gamma resulted in a twofold increase in PN-E2 antigen expression, whereas other cytokines [recombinant interleukin (rIL)-1 alpha, rIL-1 beta, rIL-4, rIL-6], lipopolysaccharide, or recombinant basic fibroblast growth factor had no effect. Immunoelectron microscopy of tissue specimens and EC preparations localized the antigen on the luminal membrane of the endothelium. Immunoprecipitation followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed a major band at 90 kDa and a minor band at 80 kDa under reducing conditions and bands of 180 and 400 kDa under non-reducing conditions. Molecular weight and expression patterns in vitro on EC after incubation with cytokines excluded most of the known endothelium-specific molecules, with the possible exception of endoglin (the 44G4 antigen). We conclude from our findings that this new antigen could be useful as a marker for endothelial activation in skin biopsy material.

Antibodies, Monoclonal↗
PubMed1993

Endothelial cells promote anti-CD3-induced T-cell proliferation via cell-cell contact mediated by LFA-1 and CD2.

T-cell activation requires not only T-cell receptor (TCR) engagement and subsequent TCR/CD3 cross-linking, but also one or more secondary activation signals generated by accessory cells (AC). We investigated the accessory function of endothelial cells (EC) in an in vitro model for T-cell activation where the first cross-linking signal was delivered to peripheral human T lymphocytes by either immobilized anti-CD3 monoclonal antibody (MoAb) or by PHA. In a previous report, we showed that EC provided a potent costimulatory signal in this model system. We have now analysed the nature of the EC-derived costimulatory signal by testing whether EC could be substituted by cytokines, by studying the effect of EC fixation and by testing the involvement of a number of adhesion molecules. Our findings indicate that EC accessory function is mediated mainly by membrane-bound factors. The nature of these membrane-bound factors was analysed by studying the inhibitory properties of a series of MoAbs directed against several adhesion molecules. Antibodies directed against CD44, E-selectin, CD31, CD26, B7/BB1, VLA-4 or VCAM-1 were not inhibitory. However, an inhibition, was clearly observed with antibodies against LFA-1 and CD2. Remarkably, this inhibition was not found with MoAbs to their respective counterstructures ICAM-1 and LFA-3. In summary, we postulate that both LFA-1/ICAM-1, and CD2/LFA-3 interactions are involved in EC accessory function, although the role of the EC-associated adhesion partners is not fully understood.

Antibodies, Monoclonal↗
PubMed1993

Angiogenesis in wound healing and tumor metastasis.

Formation of new blood vessels is essential for several physiological and pathological events, e.g. embryogenesis, wound healing and tumor growth and metastasis. In order to increase the insight into the mechanisms of angiogenesis we have visualized the different components of the microvasculature in human wounds and tumors by immunohistochemistry on the light and electronmicroscopic level. For this purpose, antibodies recognizing distinct markers for human endothelial cells, pericytes and basal lamina were used on freshly frozen or paraformaldehyde-fixed tissue samples. In terms of efficacy, the PAL-E antigen is highly specific for blood vessel endothelium. Its sensitivity is less than other endothelial markers, such as von Willebrand factor and CD 31, as it is not expressed in arterioles. Within the context of the microvasculature alpha-smooth muscle actin and the HMW-MAA chondroitin sulphate proteoglycan are useful markers for pericytes. Type IV Collagen and Laminin can be visualized consistently in the microvascular basal lamina. During the formation of granulation tissue in wound healing a heterogeneity of the expression of endothelial and pericyte markers is found. In the least matured zone in granulation tissue of decubitus lesions and experimental skin wounds microvessels already contained both endothelial cells and pericytes, suggesting a role for both cell types in the early steps of angiogenesis. Regarding the tumor microvasculature, antibodies to von Willebrand factor often failed to stain capillaries, that did show expression of the other endothelial markers studied. Broad staining in pericytes was found for the HMW-MAA chondroitin sulphate proteoglycan. In contrast, these cells only locally expressed alpha-smooth muscle actin. Staining of the basal lamina components Type IV Collagen and Laminin within tumors was not restricted to the microvasculature. Therefore, antibodies recognizing endothelial markers, particularly PAL-E and BMA 120, are preferable as tools to visualize the tumor microvasculature. In accordance with the situation in granulation tissue of wound healing the broad presence of pericytes in the microvasculature of human tumor suggests an involvement of this cell type in tumor angiogenesis. Recent immunohistochemical studies on human tumor lesions indicated that a high number of microvessels adjacent to the tumor as a measure of tumor angiogenesis is an unfavorable prognostic factor in cutaneous melanoma, mammary carcinoma and non-small cell pulmonary carcinoma. This new application of immunohistochemistry represents a valuable, clinically relevant adjunct to the repertoire of the surgical pathologist.

Animals↗
PubMed1993

Involvement of LFA-1/ICAM and CD2/LFA-3 in human endothelial cell accessory function.

Interactions of endothelial cells with T cells occur during the process of lymphocyte migration and during leukocyte extravasation in the course of an inflammatory response. Adhesion molecules are crucially involved in these interactions. It has been assumed that, in this way, endothelial cells play an important role in the recruitment of immune cells to sites of inflammation. In vitro experiments indicate that, in addition to this function in leukocyte recirculation, endothelial cells might also be involved as accessory cells in the stimulation of T cells. In this overview, the possible role of adhesion molecules in this process will be discussed.

Antigens, CD↗
PubMed1992

Accessory function of endothelial cells in anti-CD3-induced T-cell proliferation: synergism with monocytes.

Monoclonal antibodies to CD3 can induce proliferation of resting T cells. In vitro this effect is dependent on the presence of monocytes. They serve as accessory cells providing a co-stimulatory signal after cross-linking of the antibody-coated TcR/CD3 complex by the Fc receptor on the monocytes. We have studied whether endothelial cells can replace monocytes with regard to this function. Highly purified T-cell preparations were cultured in the presence of anti-CD3 antibody, purified monocytes, and human umbilical vein endothelial cells. Anti-CD3 and endothelial cells alone were unable to support T-cell proliferation, due to lack of FcR expression. Addition, however, of as few as 1000 FcR+ monocytes (0.8% of the number of T cells present) to a coculture of T cells and endothelial cells (EC) in the presence of soluble anti-CD3 resulted in a strong proliferation of T cells. When anti-CD3 was presented in an immobilized form (coated to the culture well or to Sepharose beads), or when phytohaemagglutinin was added to the culture as a cross-linking agent, EC could support T-cell proliferation in the absence of any monocytes. We conclude that EC by themselves cannot support the proliferation of pure T cells induced by soluble anti-CD3, but are potent generators of the co-stimulatory signal(s). They provide a suitable starting material to further define this co-stimulatory activity.

Antigen-Presenting Cells↗
PubMedDate not supplied

The future of organ transplant psychiatry.

The future of organ transplant psychiatry depends less on immunologic and surgical advances than on 1) an increased supply of donor organs, 2) more sophisticated multicenter outcome studies, and 3) understanding of the subjective as well as objective aspects of compliance and quality of life for transplant recipients. From future studies, we may improve the selection process for candidates and discover which approaches are optimal for anxiety, depressive, organic mental, and personality disorders. Absolute contraindications to transplantation may become relative. Integration of ethical concerns with biomedical and psychosocial criteria for selection will challenge future investigators given the inadequate supply of donor organs.

Contraindications↗
PubMedDate not supplied

EORTC Receptor and Biomarker Study Group Report: a sandwich enzyme-linked immunosorbent assay for vascular endothelial growth factor in blood and tumor tissue extracts.

A four-antibody sandwich enzyme-linked immunosorbent assay (ELISA) for vascular endothelial growth factor (VEGF) for application in blood (serum and plasma) and tumor tissue extracts was set up within the framework of the EORTC Receptor and Biomarker Study Group (RBSG). Polyclonal antibodies against VEGF165 were raised in chickens and rabbits, and used in a previously described assay format. The assay was validated and characterized for use in serum, plasma and tumor tissue extracts. The resulting VEGF ELISA was found to be specific for VEGF165 and VEGF121, the main isoforms of VEGF. The assay showed good precision and parallelism in serial dilutions of samples. The assay was not susceptible to interference by heterophilic antibodies because avian antibodies (duck anti-chicken and chicken anti-VEGF) were used in the pre-analyte stage and mammalian antibodies (rabbit anti-VEGF and goat anti-rabbit) in the post-analyte stage. In conclusion, a sensitive, robust and specific VEGF ELISA has been developed. Research into the prognostic value of VEGF employing this assay is currently underway.

Animals↗
PubMedDate not supplied

Using automated continual performance assessment to improve health care.

Inefficiency in the work of health care providers is evident and contributes to health care costs. In the early 20th century, industrial engineers developed scientific methods for studying work to improve performance (efficiency) by measuring results--i.e., quality, cost, and productivity. In the mid-20th century, business managers developed ways to apply these methods to improve the work process. These scientific methods and management approaches can be applied to improving medical work. Fee-for-service practice has had incentives to maximize productivity, and prepaid practice has had incentives to minimize costs, but no sector of the health care system has systematically pursued the optimization of all performance variables: quality, cost, and productivity. We have reviewed evolving methods for the automation of continual assessment of performance in health care using touch screen and computer telephone, logging and scheduling software, appropriate combinations of generic or disease-specific health status questionnaires, physiologic measurements or laboratory assays from computerized records, and cost and productivity data from computerized registration logs. We propose that the results of outcome assessment be rapidly and continually transmitted to providers, patients, and managers so that health care processes can be progressively improved. The evolving systems we have described are the practical tools that can help us achieve our performance goals.

Automation↗