Influence of Toso for effector function of granulocyte

Die initiale Kontrolle einer bakteriellen Infektion ist von Zellen des angeborenen Immunsystems abhängig. Opsoniert durch das Komplementsystem und von Antikörpern unterschiedlicher Isotypen werden Pathogene von Granulozyten phagozytiert und durch die intrazelluläre Synthese von reactive oxygen species (ROS) eliminiert. Störungen wie die chronischen granulomatösen Erkrankungen (CGD), die die Funktion von Granulozyten beeinträchtigen, sind häufig mit chronischen und rezidivierenden Pilz und Bakterien Infektionen assoziiert. Im Rahmen der vorliegenden Arbeit wurde die Bedeutung von fas apoptotic inhibitory molecule 3 (Faim3/Toso) mittels einer Deletionsmutante während einer Infektion mit dem Bakterium Listeria monocytogenes im Mausmodell betrachtet. Derzeit wird die funktionelle Wirkungsweise dieses Transmembranproteins als anti‐apoptotisches Molekül bzw. als Rezeptor für IgM kontrovers diskutiert. Toso defiziente Mäuse wiesen in der frühen Infektionsphase eine hohe Mortalität auf. Die spezifische Depletion der Granulozyten erhöhte die Suszeptibilität von C57BL/6 Mäusen für L. monocytogenes, wohingegen der adoptive Transfer von C57BL/6 Granulozyten die Resistenz von Toso‐/‐ Mäusen wiederherstellte. Erstmals konnte die Expression von Toso auf Granulozyten und eine durch Phagozytose bedingte Herunterregulation des Proteins beschrieben werden. Der Einfluss von Toso auf den Phagozytoseprozess von Bakterien und die Synthese von ROS konnte sowohl in vitro als auch in vivo nachgewiesen werden. Die Deletion von Toso auf Blutgranulozyten verringerte die IgM abhängige Phagozytoserate von Bakterien. Desweiteren erhöhte Toso den Schwellenwert für die Induktion der ROS‐Synthese und verhinderte eine frühzeitige Aktivierung und Degranulation der Granulozyten im Blut. Als Folge dieser Dysregulation wiesen Toso defiziente Mäuse verminderte Effektorfunktionen der Granulozyten im Gewebe und eine erhöhte Pathogenlast in den Organen auf. Im Rahmen dieser Dissertation wurde Toso als wichtiger Regulator für die Aktivierung und die Koordination der Effektorfunktionen von Granulozyten identifiziert.The initial control of bacterial infection depends on cells of the innate immune system. Pathogens which are opsonized by the complement system and antibodies of different isotypes are phagocytosed by granulocytes and eliminated by intracellular synthesis of reactive oxygen species (ROS). Disorders such as chronic granulomatous disease (CGD), which affect the function of granulocytes, are often associated with chronic and recurrent fungal and bacterial infections. In the present work, the importance of fas apoptotic inhibitory molecule 3 (Faim3/Toso) was investigated by a knockout mice during infection with the bacterium Listeria monocytogenes. Currently, there is a controversial discussion about the functional mechanism of this transmembrane protein as anti‐apoptotic molecule or a receptor for IgM. Toso deficient mice succumbed in the early phase of infection. The specific depletion of granulocytes increased susceptibility of C57BL/6 mice for L. monocytogenes, while adoptive transfer of C57BL/6 granulocytes restored resistance of Toso‐/ mice. For the first time expression of Toso on granulocytes and a phagocytosis depending downregulation of this protein were described. An influence of Toso for uptake of bacteria and synthesis of ROS were demonstrated in vitro and in vivo. The deletion of Toso on granulocytes reduced the IgM‐dependent phagocytosis of bacteria. Furthermore, Toso increased the threshold for induction of ROS synthesis and prevented early activation and degranulation of the granulocytes in the blood. As a consequence of this dysregulation Toso deficient mice showed reduced effector functions of granulocytes in tissue and increased bacterial burden in the organs. In the current thesis Toso has been identified as an important regulator for the activation and coordination of the effector functions in granulocytes

Immunological and morphological analysis of heterotopic ossification differs to healthy controls

Abstract Background Formation of lamellar bone in non-osseus tissue is a pathological process called heterotopic ossification. It is the aim of this study to analyse the morphology and immunological status of patients with heterotopic ossification compared to individual healthy persons. Methods Human bone marrow and blood samples were obtained from 6 systemically healthy individuals and 4 patients during resection of heterotopic ossification from bone at hip arthroplasty. Bone was fragmented and treated with purified collagenase. Immunofluorescence surface staining was performed and analyzed with flow cytometry. Microcomputed tomography scanning was done performed at a resolution of 11 and 35 μm isometric voxel size respectively using a two different cone beam X-computer tomography systems and a microfocus X-ray tube. Subsequently the volume data was morphometrically analysed. Results The monocytes, stem cells, stroma cells and granulocytes progenitor cells were strongly reduced in the heterotopic ossification patient. Additionally a significant reduction of stromal stem cells cells and CD34 positive stem cells was observed. The frequency of NK-cells, B cells and T cells were not altered in the patients with heterotopic ossification compared to a healthy person. Micromorphometric parameters showed a lower content of mineralized bone tissue compared to normal bone. Mean trabecular thickness showed a high standard deviation, indicating a high variation in trabecular thickness, anisotropy and reducing bone strength. Conclusions This work shows altered immunological distribution that is accompanied by a low decrease in bone volume fraction and tissue mineral density in the heterotopic ossification sample compared to normal bone. Compared to healthy subjects, this might reflect an immunological participation in the development of this entity

Antioxidants N-Acetylcysteine and Vitamin C Improve T Cell Commitment to Memory and Long-Term Maintenance of Immunological Memory in Old Mice

Aging is characterized by reduced immune responses, a process known as immunosenescence. Shortly after their generation, antigen-experienced adaptive immune cells, such as CD8+ and CD4+ T cells, migrate into the bone marrow (BM), in which they can be maintained for long periods of time within survival niches. Interestingly, we recently observed how oxidative stress may negatively support the maintenance of immunological memory in the BM in old age. To assess whether the generation and maintenance of immunological memory could be improved by scavenging oxygen radicals, we vaccinated 18-months (old) and 3-weeks (young) mice with alum-OVA, in the presence/absence of antioxidants vitamin C (Vc) and/or N-acetylcysteine (NAC). To monitor the phenotype of the immune cell population, blood was withdrawn at several time-points, and BM and spleen were harvested 91 days after the first alum-OVA dose. Only in old mice, memory T cell commitment was boosted with some antioxidant treatments. In addition, oxidative stress and the expression of pro-inflammatory molecules decreased in old mice. Finally, changes in the phenotype of dendritic cells, important regulators of T cell activation, were additionally observed. Taken together, our data show that the generation and maintenance of memory T cells in old age may be improved by targeting oxidative stress

What We Learn from Surveillance of Microbial Colonization in Recipients of Pediatric Hematopoietic Stem Cell Transplantation

Infections in hematopoietic stem cell transplant (HSCT) remain one of the major causes for morbidity and mortality, and it is still unclear whether knowledge of microbial colonization is important. In this single-center study, we collected weekly surveillance cultures in pediatric recipients of allogenic HSCT from five different body regions and tested for bacteria and fungi. Between January 2010 and December 2021, we collected 1095 swabs from 57 recipients of allogeneic HSCTs (median age: 7.5 years, IQR 1–3: 2.5–11.9). The incidence of positive microbiological cultures (n = 220; 20.1%) differed according to the anatomic localization (p n = 98), followed by the genital, pharyngeal and nasal regions (n = 55, n = 37 and n = 16, respectively). Gram-positive bacteria (70.4%) were the most commonly isolated organisms, followed by fungi (18.6%), Gram-negative (5.5%), non-fermenting bacteria (1.4%), and other flora (4.1%). No association with increased risk of infection (n = 32) or septicemia (n = 7) was noted. Over time, we did not observe any increase in bacterial resistance. We conclude that there is no benefit to surveillance of microbial colonization by culture-based techniques in pediatric HSCT. Sequencing methods might enhance the detection of pathogens, but its role is still to be defined

Increased IL-15 Production and Accumulation of Highly Differentiated CD8+ Effector/Memory T Cells in the Bone Marrow of Persons with Cytomegalovirus

Cytomegalovirus (CMV) has been described as a contributor to immunosenescence, thus exacerbating age-related diseases. In persons with latent CMV infection, the CD8+ T cell compartment is irreversibly changed, leading to the accumulation of highly differentiated virus-specific CD8+ T cells in the peripheral blood. The bone marrow (BM) has been shown to play a major role in the long-term survival of antigen-experienced T cells. Effector CD8+ T cells are preferentially maintained by the cytokine IL-15, the expression of which increases in old age. However, the impact of CMV on the phenotype of effector CD8+ T cells and on the production of T cell survival molecules in the BM is not yet known. We now show, using BM samples obtained from persons who underwent hip replacement surgery because of osteoarthrosis, that senescent CD8+ TEMRA cells with a bright expression of CD45RA and a high responsiveness to IL-15 accumulate in the BM of CMV-infected persons. A negative correlation was found between CMV antibody (Ab) titers in the serum and the expression of CD28 and IL-7Rα in CD8+TEMRAbright cells. Increased IL-15 mRNA levels were observed in the BM of CMV+ compared to CMV− persons, being particularly high in old seropositive individuals. In summary, our results indicate that a BM environment rich in IL-15 may play an important role in the maintenance of highly differentiated CD8+ T cells generated after CMV infection

Additional file 2: Figure S1. of Booster vaccination against tetanus and diphtheria: insufficient protection against diphtheria in young and elderly adults

Gating strategy for the analysis of the intracellular stainings. A representative example of CD4+ memory T cells producing IFN-γ, TNF-α, IL-2, IL-4, IL-10, IL-17, IL-21, TGF-β and GM-CSF after 6 h of tetanus toxoid (10 μg/ml) stimulation is shown (TIF 865 kb

Additional file 1: Table S1. of Booster vaccination against tetanus and diphtheria: insufficient protection against diphtheria in young and elderly adults

Complete raw data. (XLSX 30 kb

A critical evaluation of the content validity of patient-reported outcome measures assessing health-related quality of life in children with cancer: a systematic review

Abstract Background With increasing survival rates in pediatric oncology, the need to monitor health-related quality of life (HRQOL) is becoming even more important. However, available patient-reported outcome measures (PROMs) have been criticized. This review aims to systematically evaluate the content validity of PROMs for HRQOL in children with cancer. Methods In December 2021, a systematic literature search was conducted in PubMed. PROMs were included if they were used to assess HRQOL in children with cancer and had a lower age-limit between 8 and 12 years and an upper age-limit below 21 years. The COSMIN methodology for assessing the content validity of PROMs was applied to grade evidence for relevance, comprehensiveness, and comprehensibility based on quality ratings of development studies (i.e., studies related to concept elicitation and cognitive interviews for newly developed questionnaires) and content validity studies (i.e., qualitative studies in new samples to evaluate the content validity of existing questionnaires). Results Twelve PROMs were included. Due to insufficient patient involvement and/or poor reporting, the quality of most development studies was rated ‘doubtful’ or ‘inadequate’. Few content validity studies were available, and these were mostly ‘inadequate’. Following the COSMIN methodology, evidence for content validity was ‘low’ or ‘very low’ for almost all PROMs. Only the PROMIS Pediatric Profile had ‘moderate’ evidence. In general, the results indicated that the PROMs covered relevant issues, while results for comprehensiveness and comprehensibility were partly inconsistent or insufficient. Discussion Following the COSMIN methodology, there is scarce evidence for the content validity of available PROMs for HRQOL in children with cancer. Most instruments were developed before the publication of milestone guidelines and therefore were not able to fulfill all requirements. Efforts are needed to catch up with methodological progress made during the last decade. Further research should adhere to recent guidelines to develop new instruments and to strengthen the evidence for existing PROMs

Fcμ receptor as a Costimulatory Molecule for T Cells

Summary: Fc receptor for IgM (FcμR)-deficient mice display dysregulated function of neutrophils, dendritic cells, and B cells. The relevance of FcμR to human T cells is still unknown. We show that FcμR is mostly stored inside the cell and that surface expression is tightly regulated. Decreased surface expression on T cells from elderly individuals is associated with alterations in the methylation pattern of the FCMR gene. Binding and internalization of IgM stimulate transport of FcμR to the cell surface to ensure sustained IgM uptake. Concurrently, IgM accumulates within the cell, and the surface expression of other receptors increases, among them the T cell receptor (TCR) and costimulatory molecules. This leads to enhanced TCR signaling, proliferation, and cytokine release, in response to low, but not high, doses of antigen. Our findings indicate that FcμR is an important regulator of T cell function and reveal an additional mode of interaction between B and T cells. : Meryk et al. demonstrate that uptake of IgM mediated by FcμR expressed on T cells increases the surface expression of TCR and costimulatory molecules to facilitate T cell activation, particularly when antigen concentrations are low. Consequently, FcμR increases TCR signaling, proliferation, and cytokine release. Keywords: FcμR, IgM, T cells, TCR activatio