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Altered peptide ligands (APL) have the potential to modulate pathogenic T cell reactivity. High concentrations of APL, however, are required to achieve efficient blocking of the T cell response. We have therefore investigated whether improved delivery of APL to professional antigen-presenting cells (APC) can lead to more efficient application of such peptides. For this purpose APL were bis-mannosylated in order to facilitate their uptake by mannose receptor-positive dendritic cells (DC) in vitro. We present evidence that a 100- to 1000-fold lower concentration of bis-mannosylated APL were similarly effective in the inhibition of the T cell response against whole protein antigens. In contrast, unrelated, bis-mannosylated class II binding peptides were ineffective, indicating that the increased efficiency of the mannosylated APL was not due to competition for binding to class II molecules. Furthermore, a strong increase in the efficiency of presentation of APL was also observed when macrophages and peripheral blood mononuclear cells were used as APC. Thus, bis-mannosylation of APL greatly increases their potency to inhibit proliferative T cell responses. Moreover, it is likely that the use of bis-mannosylated APL will result in preferential presentation by mannose receptor-positive, professional APC. These results may be of relevance for more effective use of APL for immunoregulation in vivo. [ABSTRACT FROM PUBLISHER]

Background: Dialysis patients are confronted with numerous, complex problems, which make it difficult to identify individual patient's most prominent problems. The objectives of this study were to (1) identify dialysis patients' most prominent problems from a patient perspective and (2) to calculate disease-specific norms for questionnaires measuring these problems., Methods: One hundred seventy-five patients treated with hemodialysis or peritoneal dialysis completed a priority list on several domains of functioning (e.g., physical health, mental health, social functioning, and daily activities) and a set of matching questionnaires assessing patient functioning on these domains. Patient priorities were assessed by calculating the importance ranking of each domain on the priority list. Subsequently, disease-specific norm scores were calculated for all questionnaires, both for the overall sample and stratified by patient characteristics., Results: Fatigue was listed as patients' most prominent problem. Priorities differed between male and female patients, younger and older patients, and home and center dialysis patients, which was also reflected in their scores on the corresponding domains of functioning. Therefore, next to general norm scores, we calculated corrections to the general norms to take account of patient characteristics (i.e., sex, age, and dialysis type)., Conclusions: Results highlight the importance of having attention for the specific priorities and needs of each individual patient. Adequate disease-specific, norm-based assessment is not only necessary for diagnostic procedures but is an essential element of patient-centered care: It will help to better understand and respect individual patient needs and tailor treatment accordingly., (© 2022 The Authors. Seminars in Dialysis published by Wiley Periodicals LLC.)

Objectives: Dialysis patients report a low health-related quality of life (HRQOL) due to high disease burden and far-reaching consequences of dialysis treatment. This study examined several cognitive-behavioral and social factors, with a focus on negative outcome expectancies, that might be relevant for HRQOL in end-stage kidney disease (ESKD) patients treated with dialysis., Methods: Patients treated with hemodialysis or peritoneal dialysis were recruited from Dutch hospitals and dialysis centers. Patients completed self-report questionnaires at baseline (n = 175) and six months follow-up (n = 130). Multiple regression analyses were performed., Results: Higher scores on factors related to negative outcome expectancies at baseline, especially helplessness and worrying, and less perceived social support were significantly related to worse HRQOL six months later. When controlling for baseline HRQOL, besides sex and comorbidity, helplessness remained significantly predictive of worse HRQOL six months later, indicating that helplessness is associated with changes in HRQOL over time., Conclusions: Negative outcome expectancies and social support are relevant markers for HRQOL and/or changes in HRQOL over time., Practice Implications: Negative outcome expectancies could be prevented or diminished by enhanced treatment information, an improved patient-clinician relationship, and interventions that promote adaptive and realistic expectations. Additionally, increasing supportive social relationships could be a relevant treatment focus., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 The Authors. Published by Elsevier B.V. All rights reserved.)

Chronic infection with helminths is associated with down-regulated antigen-specific T cell responses. In order to determine whether schistosome-specific T cells are present, yet functionally unresponsive, or absent in the periphery of chronically infected persons, autologous granulocyte-macrophage colony-stimulating factor and dendritic cells (DC) derived from interleukin (IL)-4 were used as highly efficient antigen-presenting cells (APC). Peripheral blood mononuclear cells (PBMC) from persons harboring Schistosoma haematobium infection and hyporesponsive to parasite antigen were cocultured with autologous DC in the presence of adult worm antigen (AWA). In contrast to PBMC alone, DC-supplemented cultures responded to AWA by proliferation and by IL-4 and IL-5 production and, in some patients, by production of interferon-gamma. Thus, schistosome-specific T helper cells are present in the periphery but are functionally hyporesponsive during active infection with schistosomes. Cytokine responses representing the Th1 and (more importantly) Th2 types can be restored in vitro when DC are used as APC.

The activation of MHC class II-restricted helper T cells is paramount to adaptive immune responses. Vaccine development could therefore benefit from improved ways of targeting antigens into MHC class II molecules. In recent years, the natural pathways of MHC class II antigen presentation have been exploited to achieve this goal. First, antigenic proteins and peptides have been modified to facilitate receptor-mediated uptake by professional antigen-presenting cells. Second, DNA constructs containing specific targeting sequences have been used to direct endogenously synthesized antigens to the MHC class II compartments. Both strategies proved to be highly effective. We review these data and describe how this knowledge is currently applied to the design of vaccines that activate helper T cells in vivo.

Langerhans cells (LC) represent the dendritic cell (DC) lineage in the epidermis. They capture and process antigens in the skin and subsequently migrate to the draining lymph nodes to activate naive T cells. Efficient uptake and processing of protein antigens by LC would, therefore, seem a prerequisite. We have now compared the capacity of human epidermal LC, blood-derived DC and peripheral blood mononuclear cells to endocytose and present (mannosylated) antigens to antigen-specific T cells. Moreover, we have determined the expression of mannose receptors, and the composition of the intracellular endosomal/lysosomal MHC class II-positive compartment. The results indicate that LC have poor endocytic capacity and do not exploit mannose receptor-mediated endocytosis pathways. Furthermore, the composition of the class II compartment in LC is distinct from that in other antigen-presenting cells and is characterized by the presence of relatively low levels of lysosomal markers. These results underscore the unique properties of LC and indicate that LC are relatively inefficient in antigen uptake, processing and presentation. This may serve to avoid hyper-responsiveness to harmless protein antigens that are likely to be frequently encountered in the skin due to (mechanical) skin damage.

Dendritic cells (DC) efficiently take up antigens by macropinocytosis and mannose receptor-mediated endocytosis. Here we show that endocytosis of mannose receptor-antigen complexes takes place via small coated vesicles, while non-mannosylated antigens were mainly present in larger vesicles. Shortly after internalization the mannose receptor and its ligand appeared in the larger vesicles. Within 10 min, the mannosylated and non-mannosylated antigens co-localized with typical markers for major histocompatibility complex class II-enriched compartments and lysosomes. In contrast, the mannose receptor appeared not to reach these compartments, suggesting that it releases its ligand in an earlier endosomal structure. Moreover, we demonstrate that mannosylation of protein antigen and peptides resulted in a 200-10,000-fold enhanced potency to stimulate HLA class II-restricted peptide-specific T cell clones compared to non-mannosylated peptides. Our results indicate that mannosylation of antigen leads to selective targeting and subsequent superior presentation by DC which may be applicable in vaccine design.

To optimize growth and Ig production of in vitro-cultured Epstein-Barr virus (EBV)-transformed B cells, a panel of six monoclonal EBV B-cell lines was analyzed for autocrine growth factor production and responsiveness to various cytokines. Three cell lines produced Il-I and four produced Il-6, although differences concerning the amount of lymphokines produced were observed. Interestingly a considerable tumor necrosis factor beta (lymphotoxin) activity was found in supernatants of all cell lines. One IgM-producing cell line that did not secrete either Il-1 or Il-6 was exceptional in its ability to respond to the addition of rIl-6 with a 5- to 10-times elevated IgM production. In contrast, cell lines in the panel capable of Il-6 production showed only a minimal elevation of Ig production on addition of exogenous Il-6. Ig production was slightly less in some cell lines when Il-6 was neutralized. Antibodies against lymphotoxin or Il-6 did not influence growth rate of the cell lines significantly, implying that neither Il-6 nor lymphotoxin had an autostimulatory effect on the analyzed cell lines. This study demonstrates a heterogeneity regarding the amount and type of lymphokines produced by long-term monoclonal EBV cell lines, which may account for the diverse responses exhibited by these cells towards exogenously added lymphokines.

To optimalize growth and Ig production of EBV transformed B cells for large scale tissue culture, we analyzed five stable monoclonal EBV-B cell lines for their responsiveness to interleukin (IL)-6 in standard medium with 5% FCS and in several serum-free media. As we previously demonstrated these cell lines were found to be heterogeneous with regard to their production of Il-1, Il-6 and lymphotoxin. We could not demonstrate an effect of Il-6 on proliferation on any of the cell lines in either standard medium with 5% FCS or in any of the serum-free culture media. In standard medium, cell lines capable of Il-6 production showed a slight elevation of Ig production in response to exogenous Il-6. Only one cell line, that did not secrete any of the lymphokines tested, responded strongly to Il-6 with a 12 times elevated IgM production. In contrast, in serum-free medium supplemented with Bovine Serum Albumin (BSA), Il-6 raised Ig secretion of all cell lines. This study shows that in some serum-free culture media EBV cell lines can be propagated as well as in standard medium with FCS. Responsiveness of these cells to cytokines is heterogeneous and is at least partially influenced by the culture medium used.