Expression of HLA-DR Antigen in Skin from Patients with Psoriasis

Using murine monoclonal antibodies against human HLA-DR antigen and against human T cells, we investigated the indirect immunofluorescence staining pattern of involved and uninvolved skin from patients with psoriasis. The staining pattern of involved psoriatic epidermis is different from the pattern seen in uninvolved skin from the same patient and consists of scattered, single HLA-DR positive cells alternating with groups of HLA- DR positive cells. These HLA-DR positive cell clusters can be seen at any level of the epidermis. In some patients, the dermis of involved skin shows prominent accumulations of T cells which are HLA-DR positive and thus represent activated T cells

Induction of the Synthesis of Triton-Soluble Proteins in Human Keratinocytes by Gamma Interferon

Recombinant human gamma interferon (r-IFN-γ) induces the synthesis and expression of HLA-DR antigen on cultured, normal, human keratinocytes depleted of Langerhans cells. After removal of r-IFN-γ from the culture medium of keratinocytes that are expressing HLA-DR antigen, the cells continue to express this antigen for at least 2 days. r-IFN-γ induces, in a dose dependent fashion, the synthesis of several triton-soluble proteins with the most prominent having an apparent molecular weight of 53,000. Whereas normal keratinocytes do not express HLADR antigen in vivo, they do express HLA-DR in a variety of skin diseases such as lichen planus, graft-versushost disease, and mycosis fungoides. We propose that an understanding of lymphocyte-keratinocyte interactions in vivo may be achieved by further studies of the mechanism of action of r-IFN-γ on cultured keratinocytes and that the results may provide insight into the pathophysiology leading to a number of common inflammatory and neoplastic skin diseases

Effects of Recombinant Interleukin 1 and Interleukin 2 on Human Keratinocytes

The effects of recombinant interleukin 1 alpha and beta, as well as recombinant interleukin 2, on human keratinocyte proliferation were studied in serum-containing as well as defined media. Both interleukin 1 preparations did not stimulate keratinocyte growth; interleukin 2 also did not stimulate keratinocyte growth. To determine whether interleukin 1 beta binds to keratinocytes, a cell membrane assay was developed for these cells. Iodinated interleukin 1 beta binds to keratinocytes with a kD of 6.2nm and 2500 receptors per cell. To determine the effects of interleukin 1 beta on protein synthesis, the molecular patterns of radiolabeled cell extracts of interleukin 1 beta-treated and nontreated keratinocytes were compared using two-dimensional polyacrylamide gel electrophoresis. No significant changes in the molecular pattern of newly synthesized proteins were detected. Finally, none of these lymphokines induced HLA-DR expression by keratinocytes

Cultured Human Epidermal Cells Do Not Synthesize HLA-DR

All nucleated cells express HLA-A, B, and C antigens. However, only a few cells, including epidermal cells, demonstrate HLA-DR antigens which are potent transplantation immunogens in man. The current study was undertaken to determine if epidermal cells continue to synthesize and/or express HLA-DR antigens after prolonged in vitro culture. Epidermal cells cultured for 7days or more no longer stimulated allogeneic lymphocytes in the epidermal cell-lymphocyte reaction. Indirect immunofluorescence light microscopy of cultured cells using mouse monoclonal antibody to HLA-DR antigen confirmed that these cells do not express HLA-DR antigens whereas they retain β2-microglobulin. Detergent extracts of 12-day cultured epidermal cells biosynthetically labeled with 35S-methionine were immunoprecipitated with monoclonal anti-DR antibody and analyzed by the method of two-dimensional polyacrylamide gel electrophoresis. No radiolabeled proteins were found on these gels in the regions where HLA-DR molecules are known to migrate. These data indicate that HLA-DR antigen is absent from cultured epidermal cells. Finally, we describe a technique for growing epidermal cells on a gelatin membrane which allows subsequent removal of intact cell monolayers from the culture dish. Such monolayers may be useful for purposes of transplantation

Inhibition of a Langerhans Cell-Mediated Immune Response by Treatment Modalities Useful in Psoriasis

Neither the pathogenesis of psoriasis nor the mechanism whereby seemingly diverse therapies alter the disease is understood. In this study, several antipsoriatic agents were tested for their effects on the skin cell lymphocyte reaction (SLR), an immunologic assay in which HLA-DR antigens on Langerhans cells (LC) stimulate proliferation of allogeneic lymphocytes. Every agent tested (cortisol, methotrexate, hyperthermia, anthralin) inhibited the SLR at therapeutic dose levels. By contrast, a variety of antibiotics, an anti-inflammatory agent, and lithium carbonate and propranolol, two drugs known to be ineffective in psoriasis, failed to inhibit the SLR. Finally, we have shown that hyperthermia and anthralin treatments are toxic for LC whereas they have little or no effect on keratinocyte viability. These results suggest that antipsoriatic agents may act in psoriasis by alteration or killing of LC

Use of the Fluorescence-Activated Cell Sorter to Quantitate and Enrich for Subpopulations of Human Skin Cells

A variety of immunologic staining techniques were compared in a quantitative study of antigen expression by human epidermal cells. Virtually all nucleated epidermal cells express β2-microglobulin, which is associated with HLA-A, -B, and -C antigens, whereas only about 4% expressed T6, an antigen expressed by Langerhans cells but not other cells in the skin. With the fluorescence-activated cell sorter (FACS), epidermal cell suspensions were selectively enriched 10- to 15-fold for T6-positive Langerhans cells.An average of 6.5% of cells were specifically stained by anti-HLA-DR antibody. When dispersed cells stained with anti-DR plus peroxidase were examined with the technique of immunoelectron microscopy, only mononuclear leukocytes (probably Langerhans cells) were stained. After separating HLA-DR positive skin cells with the FACS, the DR-positive population but not the DR-negative population stimulated proliferation of allogeneic responder lymphocytes, indicating that sorted cells are metabolically active. We conclude that HLA-DR antigen is not expressed by keratinocytes in normal human skin cell suspensions and that the FACS can be used to selectively enrich or deplete skin cell suspensions of antigenically distinct subpopulations such as Langerhans cells

Status Quo of Progress Testing in Veterinary Medical Education and Lessons Learned

Progress testing is an assessment tool for longitudinal measurement of increase in knowledge of a specific group, e.g., students, which is well-known in medical education. This article gives an overview of progress testing in veterinary education with a focus on the progress test of the German-speaking countries. The "progress test veterinary medicine" (PTT) was developed in 2013 as part of a project by the Competence Centre for E-Learning, Didactics and Educational Research in Veterinary Medicine-a project cooperation of all German-speaking institutes for veterinary medicine in Germany, Austria, and Switzerland. After the end of the project, the PTT was still continued at six locations, at each of the five German schools for veterinary medicine and additionally in Austria. Further changes to the PTT platform and the analysis were carried out to optimize the PTT for continuing to offer the test from 2017 to 2019. The PTT is an interdisciplinary, formative electronic online test. It is taken annually and is composed of 136 multiple-choice single best answer questions. In addition, a "don't know" option is given. The content of the PTT refers to the day 1 competencies described by the European Association of Establishments for Veterinary Education. The platform Q-Exam (R) Institutions (IQuL GmbH, Bergisch Gladbach, Germany) is used for creating and administrating the PTT questions, the review processes and organizing of the online question database. After compiling the test by means of a blueprint, the PTT file is made available at every location. After the last PTT in 2018, the link to an evaluation was sent to the students from four out of these six partner Universities. The 450 analyzed questionnaires showed that the students mainly use the PTT to compare their individual results with those of fellow students in the respective semester. To conclude our study, a checklist with our main findings for implementing progress testing was created

Integration and potential of teaching communication skills in the study of veterinary medicine in Germany

Goal: Presentation of the current range of courses regarding communication at the five German educational institutions for veterinary medicine. In addition to learning objectives and individual solutions, possible potential for future developments are presented. Methods: Interviews with communication educators at the five German education institutions and subsequent synopsis. Results: To date, there are no binding education guidelines regarding communication in veterinary medicine. Nevertheless, communication education has been introduced at all five education institutions, albeit depth and formats vary considerably. The learning objectives are largely consistent and based on the recommendations for day-one-skills made by the European Association of Establishments for Veterinary Education. Communication is not recognized as a fully-fledged subject in the curricula of any of the education institutions. All education institutions clearly fall short of teaching the recommended 150 lecture hours. Conclusion: To ensure communication skills in veterinary medicine graduates, binding education guidelines should be agreed upon. Communication education should be integrated into all veterinary curricula as a fully-fledged subject with longitudinally increasing depth