Comparative analysis of swine leukocyte antigen gene diversity in Göttingen Minipigs

Worldwide, pigs represent economically important farm animals, also representing a preferred preclinical large animal model for biomedical studies. The need for swine leukocyte antigen (SLA) typing is increasing with the expanded use of pigs in translational research, infection studies, and for veterinary vaccine design. Göttingen Minipigs (GMP) attract increasing attention as valuable model for pharmacological studies and transplantation research. This study represents a first-time assessment of the SLA gene diversity in Göttingen Minipigs in combination with a comparative metadata analysis with commercial pig lines. As Göttingen Minipigs could harbor private as well as potential novel SLA allele combinations, future research projects would benefit from the characterization of their SLA background. In 209 Göttingen Minipigs, SLA class I (SLA-1, SLA-2, SLA-3) and class II (DRB1, DQB1, DQA) genes were characterized by PCR-based low-resolution (Lr) haplotyping. Criteria and nomenclature used for SLA haplotyping were proposed by the ISAG/IUIS-VIC SLA Nomenclature Committee. Haplotypes were assigned based on the comparison with already known breed or farm-specific allele group combinations. In total, 14 SLA class I and five SLA class II haplotypes were identified in the studied cohort, to manifest in 26 SLA class I but only seven SLA class II genotypes. The most common SLA class I haplotypes Lr-24.0 (SLA-1*15XX or Blank-SLA-3*04:04-SLA-2*06:01~02) and Lr-GMP-3.0 (SLA-1*16:02-SLA-3*03:04-SLA-2*17:01) occurred at frequencies of 23.44 and 18.66%, respectively. For SLA class II, the most prevalent haplotypes Lr-0.21 (DRB1*01XX-DQB1*05XX-DQA*04XX) and Lr-0.03 (DRB1*03:02-DQB1*03:01-DQA*01XX) occurred at frequencies of 38.28 and 30.38%. The comparative metadata analysis revealed that Göttingen Minipigs only share six SLA class I and two SLA class II haplotypes with commercial pig lines. More importantly, despite the limited number of SLA class I haplotypes, the high genotype diversity being observed necessitates pre-experimental SLA background assessment of Göttingen Minipigs in regenerative medicine, allo-transplantation, and xenograft research.

Human PD-L1 overexpression decreases xenogeneic human T-cell immune responses towards porcine kidneys

Xenotransplantation offers a promising alternative to circumvent the lack of donated human organs available for transplantation. Different attempts to improve the survival of xenografts led to the generation of transgenic pigs expressing various combinations of human protective genes or knocked out for specific antigens. Currently, testing the efficiency of porcine organs carrying different genetic modifications in preventing xenogeneic immune responses completely relies on in vitro assays, humanized mouse models, or non-human primate transplantation models. However, these tests are often associated with major concerns due to reproducibility and generation of insufficient data as well as they raise ethical, logistical, and economic issues. In this study, we investigated the feasibility of specifically assessing the strength of human T-cell responses towards the kidneys of wild-type (WT) or transgenic pigs overexpressing human programmed death-1 ligand 1 (hPD-L1) during ex vivo kidney perfusion (EVKP). Human T cells were shown to adhere to the endothelium and transmigrate into WT and hPD-L1 kidneys. However, transcript levels of TNF-a and IFN-y as well as cytotoxic molecules such as granzyme B and perforin secreted by human T cells were significantly decreased in the tissue of hPD-L1 kidneys in comparison to WT kidneys. These results were confirmed via in vitro assays using renal endothelial cells (ECs) isolated from WT and hPD-L1 transgenic pigs. Both CD4+ and CD8+ T cells showed significantly lower proliferation rates after exposure to hPD-L1 porcine renal ECs in comparison to WT ECs. In addition, the secretion of pro-inflammatory cytokines was significantly reduced in cultures using hPD-L1 ECs in comparison to WT ECs. Remarkably, hPD-L1 EC survival was significantly increased in cytotoxic assays. This study demonstrates the feasibility of evaluating the human response of specific immune subsets such as human T cells towards the whole xenograft during EVKP. This may represent a robust strategy to assess the potency of different genetic modifications to prevent xenogeneic immune responses and thereby predict the risk of immune rejection of new genetically engineered xenografts.

Downregulation of Swine Leukocyte Antigen Expression Decreases the Strength of Xenogeneic Immune Responses towards Renal Proximal Tubular Epithelial Cells

Xenotransplantation reemerged as a promising alternative to conventional transplantation enlarging the available organ pool. However, success of xenotransplantation depends on the design and selection of specific genetic modifications and on the development of robust assays allowing for a precise assessment of tissue-specific immune responses. Nevertheless, cell-based assays are often compromised by low proliferative capacity of primary cells. Proximal tubular epithelial cells (PTECs) play a crucial role in kidney function. Here, we generated immortalized PTECs (imPTECs) by overexpression of simian virus 40 T large antigen. ImPTECs not only showed typical morphology and phenotype, but, in contrast to primary PTECs, they maintained steady cell cycling rates and functionality. Furthermore, swine leukocyte antigen (SLA) class I and class II transcript levels were reduced by up to 85% after transduction with lentiviral vectors encoding for short hairpin RNAs targeting β2-microglobulin and the class II transactivator. This contributed to reducing xenogeneic T-cell cytotoxicity (p < 0.01) and decreasing secretion of pro-inflammatory cytokines such as IL-6 and IFN-γ. This study showed the feasibility of generating highly proliferative PTECs and the development of tissue-specific immunomonitoring assays. Silencing SLA expression on PTECs was demonstrated to be an effective strategy to prevent xenogeneic cellular immune responses and may strongly support graft survival after xenotransplantation.

Non-viral TRAC-knocked-in CD19KICAR-T and gp350KICAR-T cells tested against Burkitt lymphomas with type 1 or 2 EBV infection: In vivo cellular dynamics and potency

Introduction

The ubiquitous Epstein-Barr virus (EBV) is an oncogenic herpes virus associated with several human malignancies. EBV is an immune-evasive pathogen that promotes CD8⁺ T cell exhaustion and dysregulates CD4⁺ T cell functions. Burkitt lymphoma (BL) is frequently associated with EBV infections. Since BL relapses after conventional therapies are difficult to treat, we evaluated prospective off-the-shelf edited CAR-T cell therapies targeting CD19 or the EBV gp350 cell surface antigen.

Methods

We used CRISPR/Cas9 gene editing methods to knock in (KI) the CD19CAR.CD28z or gp350CAR.CD28z into the T cell receptor (TCR) alpha chain (TRAC) locus.

Results

Applying upscaled methods with the ExPERT ATx^® MaxCyte system, KI efficacy was ~20% of the total ~2 × 10⁸ TCR-knocked-out (KO) generated cells. ^KOTCR^KICAR-T cells were co-cultured in vitro with the gp350⁺CD19⁺ BL cell lines Daudi (infected with type 1 EBV) or with Jiyoye (harboring a lytic type 2 EBV). Both types of CAR-T cells showed cytotoxic effects against the BL lines in vitro. CD8^{+ KI}CAR-T cells showed higher persistency than CD4^{+ KI}CAR-T cells after in vitro co-culture with BL and upregulation of the activation/exhaustion markers PD-1, LAG-3, and TIM-3. Two preclinical in vivo xenograft models were set up with Nod.Rag.Gamma mice injected intravenously (i.v.) with 2 × 10⁵ Daudi/fLuc-GFP or with Jiyoye/fLuc-GFP cells. Compared with the non-treated controls, mice challenged with BL and treated with CD19^KICAR-T cells showed delayed lymphoma dissemination with lower EBV DNA load. Notably, for the Jiyoye/fLuc-GFP model, almost exclusively CD4⁺ CD19^KICAR-T cells were detectable at the endpoint analyses in the bone marrow, with increased frequencies of regulatory T cells (T_regs) and TIM-3⁺CD4⁺ T cells. Administration of gp350^KICAR-T cells to mice after Jiyoye/GFP-fLuc challenge did not inhibit BL growth in vivo but reduced the EBV DNA load in the bone marrow and promoted gp350 antigen escape. CD8⁺PD-1⁺LAG-3⁺ gp350^KICAR-T cells were predominant in the bone marrow.

Discussion

The two types of ^KOTCR^KICAR-T cells showed different therapeutic effects and in vivo dynamics. These findings reflect the complexities of the immune escape mechanisms of EBV, which may interfere with the CAR-T cell property and potency and should be taken into account for future clinical translation.

Discoid lupus in antiphospholipid syndrome: case description and literature review

OBJECTIVE

The aim of the study was to report about a patient with discoid lupus erythematosus (DLE) who developed antiphospholipid syndrome (APS) 12 years after DLE diagnosis and review related literature.

PATIENTS AND METHODS

This is a case report of a 34-year-old woman with DLE who developed APS. A review of articles published in the PubMed/MEDLINE, LILACS, and SciELO databases from 1966 to October 2020 was conducted using the following search terms: "antiphospholipid syndrome," "antiphospholipid antibodies," and "discoid lupus erythematosus" No language limitation was applied.

RESULTS

Besides the present case, 5 case reports were identified. One case-control and two cross-sectional studies on antiphospholipid antibodies with or without APS in DLE were also reviewed. These studies revealed that APS can develop even 37 years after DLE was diagnosed. The case-control study found that patients with DLE have more anticardiolipin antibodies than controls. In contrast, one cross-sectional study showed a low prevalence of antiphospholipid antibodies in their group of patients, which was similar to findings in the general population.

CONCLUSIONS

This study reviewed previous articles on DLE cases associated with antiphospholipid antibodies and/or APS, adding a new case description.

Genetic Modification of Limbal Stem Cells to Decrease Allogeneic Immune Responses

Limbal stem cell (LSC) transplantation is the only efficient treatment for patients affected by LSC deficiency (LSCD). Allogeneic LSC transplantation is one of the most successful alternative for patients with bilateral LSCD. Nevertheless, the high variability of the human leukocyte antigens (HLA) remains a relevant obstacle to long-term allogeneic graft survival. This study characterized the immunologic properties of LSCs and proposed a genetic engineering strategy to reduce the immunogenicity of LSCs and of their derivatives. Hence, LSC HLA expression was silenced using lentiviral vectors encoding for short hairpin (sh) RNAs targeting β2-microglobulin (β2M) or class II major histocompatibility complex transactivator (CIITA) to silence HLA class I and II respectively. Beside the constitutive expression of HLA class I, LSCs showed the capability to upregulate HLA class II expression under inflammatory conditions. Furthermore, LSCs demonstrated the capability to induce T-cell mediated immune responses. LSCs phenotypical and functional characteristics are not disturbed after genetic modification. However, HLA silenced LSC showed to prevent T cell activation, proliferation and cytotoxicity in comparison to fully HLA-expressing LSCs. Additionally; HLA-silenced LSCs were protected against antibody-mediated cellular-dependent cytotoxicity. Our data is a proof-of-concept of the feasibility to generate low immunogenic human LSCs without affecting their typical features. The use of low immunogenic LSCs may support for long-term survival of LSCs and their derivatives after allogeneic transplantation.

Generation of HLA Universal Megakaryocytes and Platelets by Genetic Engineering

Patelet transfusion refractoriness remains a relevant hurdle in the treatment of severe alloimmunized thrombocytopenic patients. Antibodies specific for the human leukocyte antigens (HLA) class I are considered the major immunological cause for PLT transfusion refractoriness. Due to the insufficient availability of HLA-matched PLTs, the development of new technologies is highly desirable to provide an adequate management of thrombocytopenia in immunized patients. Blood pharming is a promising strategy not only to generate an alternative to donor blood products, but it may offer the possibility to optimize the therapeutic effect of the produced blood cells by genetic modification. Recently, enormous technical advances in the field of in vitro production of megakaryocytes (MKs) and PLTs have been achieved by combining progresses made at different levels including identification of suitable cell sources, cell pharming technologies, bioreactors and application of genetic engineering tools. In particular, use of RNA interference, TALEN and CRISPR/Cas9 nucleases or nickases has allowed for the generation of HLA universal PLTs with the potential to survive under refractoriness conditions. Genetically engineered HLA-silenced MKs and PLTs were shown to be functional and to have the capability to survive cell- and antibody-mediated cytotoxicity using in vitro and in vivo models. This review is focused on the methods to generate in vitro genetically engineered MKs and PLTs with the capacity to evade allogeneic immune responses.

Genetic modification of limbs using ex vivo machine perfusion

Genetic engineering is a promising tool to repair genetic disorders, improve graft function or to reduce immune responses towards the allografts. Ex vivo organ perfusion systems have the potential to mitigate ischemic-reperfusion injury, prolong preservation time or even rescue organ function. We aim to combine both technologies to develop a modular platform allowing the genetic modification of vascularized composite (VC) allografts. Rat hind limbs were perfused ex vivo under subnormothermic conditions with lentiviral vectors. Specific perfusion conditions such as controlled pressure, temperature and flow rates were optimized to support the genetic modification of the limbs. Genetic modification was detected in vascular, muscular and dermal limb tissues. Remarkably, skin follicular and interfollicular keratinocytes as well as endothelial cells (ECs) showed stable transgene expression. Furthermore, levels of injury markers such as lactate, myoglobin and lactate dehydrogenase (LDH) as well as histological analyses showed that ex vivo limb perfusion with lentiviral vectors did not cause tissue damage and limb cytokine secretion signatures were not significantly affected. The use of ex vivo VC perfusion in combination with lentiviral vectors allows an efficient and stable genetic modification of limbs representing a robust platform to genetically engineer limbs towards increasing graft survival after transplantation.

Developing evidence on social prescribing initiative in Lisbon: Challenges and insights for improving

Social prescribing is recent in Portugal and evidence is needed on the potential of this complex intervention to improve health and wellbeing outcomes but also to inform the commissioning of these programmes. In a collaborative approach, an evaluation protocol of the social prescribing in two primary healthcare units in Lisbon was developed, aiming to assess its implementation and impact at three levels: patients, health system and health-social sector intersection, within a mixed-methods approach. Exploring the social prescribing contribution to enhance patients' quality of life, well-being and activation involves assessing these outcomes throughout a longitudinal perspective. In an exploratory, prospective study, baseline data collection and three follow-ups are included. Secondary data comprise health status indicators collected from patients' medical records as well as referral and social responses elaborated within the intervention. Patients' experiences on the social prescribing activities performed, perceived changes in lifestyle, and perspectives about positive and negative aspects are assessed in semi-structured interviews. The need for further understanding the impact at the health system' level calls for an attentive look at the processes of change in patients' patterns of healthcare services use (appointments in primary healthcare units, hospital admissions and emergency episodes), but also changes in the services' reorganization to better integrative health care. At a broader level, insights will be obtained on the effects on the intersection between the health and social sectors and the experiences of networking, through focus group discussions with all the stakeholders involved. The social prescribing implementation process, barriers, facilitators and suggestions for improvement will also be explored. In this presentation, challenges will be debated, as well as insights for reflection about opportunities for improving evidence development.

Exogenous attention to social stimuli in the neurotypical population: The impact of autism traits

Introduction

Autism Spectrum Disorders (ASD) have been associated with decreased spontaneous attention to social stimuli. Several studies further suggest that a higher expression of autism traits (AT) in the neurotypical population (NTP) may also be related to decreased social attention, although the evidence is still scarce, especially when considering faces as task-irrelevant distractors.

Objectives

This study aimed to explore the relationship between the expression of AT in the NTP and exogenous attention to social stimuli.

Methods

Fifty-one adult participants were recruited and asked to complete the Autism Spectrum Quotient (AQ), to measure AT, and to perform an attentional capture task. In the latter, they were instructed to detect a target letter in the middle of perceptually similar (high perceptual load) or dissimilar (low perceptual load) distractor letters. In 25% of the trials, task-irrelevant distractors, consisting of images of faces (social) or houses (non-social), were shown flanking the letter stimuli.

Results

Response times were found to be affected by distractor-response compatibility, increasing for contralateral distractors, but decreasing for ipsilateral distractors, in relation to trials with no distractors (baseline). Importantly, these trends were magnified for distractor faces in the group with less AT, considering the social skills dimension of AQ, while the same tendency was observed in the group with higher AT, but for distractor houses.

Conclusions

Our results support an altered attentional performance in the subclinical phenotype of the autism spectrum. Furthermore, they also add to existing literature documenting similar attentional abnormalities in both the clinical and subclinical extremes of the spectrum, hinting possible shared mechanisms.

Disclosure

No significant relationships.

Induced dendritic cells co-expressing GM-CSF/IFN-α/tWT1 priming T and B cells and automated manufacturing to boost GvL

Acute myeloid leukemia (AML) patients with minimal residual disease and receiving allogeneic hematopoietic stem cell transplantation (HCT) have poor survival. Adoptive administration of dendritic cells (DCs) presenting the Wilms tumor protein 1 (WT1) leukemia-associated antigen can potentially stimulate de novo T and B cell development to harness the graft-versus-leukemia (GvL) effect after HCT. We established a simple and fast genetic modification of monocytes for simultaneous lentiviral expression of a truncated WT1 antigen (tWT1), granulocyte macrophage-colony-stimulating factor (GM-CSF), and interferon (IFN)-α, promoting their self-differentiation into potent “induced DCs” (iDCtWT1). A tricistronic integrase-defective lentiviral vector produced under good manufacturing practice (GMP)-like conditions was validated. Transduction of CD14⁺ monocytes isolated from peripheral blood, cord blood, and leukapheresis material effectively induced their self-differentiation. CD34⁺ cell-transplanted Nod.Rag.Gamma (NRG)- and Nod.Scid.Gamma (NSG) mice expressing human leukocyte antigen (HLA)-A∗0201 (NSG-A2)-immunodeficient mice were immunized with autologous iDCtWT1. Both humanized mouse models showed improved development and maturation of human T and B cells in the absence of adverse effects. Toward clinical use, manufacturing of iDCtWT1 was up scaled and streamlined using the automated CliniMACS Prodigy system. Proof-of-concept clinical-scale runs were feasible, and the 38-h process enabled standardized production and high recovery of a cryopreserved cell product with the expected identity characteristics. These results advocate for clinical trials testing iDCtWT1 to boost GvL and eradicate leukemia.

Immunogenetics of xenotransplantation

Xenotransplantation may become the highly desired solution to close the gap between the availability of donated organs and number of patients on the waiting list. In recent years, enormous progress has been made in the development of genetically engineered donor pigs. The introduced genetic modifications showed to be efficient in prolonging xenograft survival. In this review, we focus on the type of immune responses that may target xeno-organs after transplantation and promising immunogenetic modifications that show a beneficial effect in ameliorating or eliminating harmful xenogeneic immune responses. Increasing histocompatibility of xenografts by eliminating genetic discrepancies between species will pave their way into clinical application.

Human Amniotic Membrane: A review on tissue engineering, application, and storage

Human amniotic membrane (hAM) has been employed as scaffolding material in a wide range of tissue engineering applications, especially as a skin dressing and as a graft for corneal treatment, due to the structure of the extracellular matrix and excellent biological properties that enhance both wound healing and tissue regeneration. This review highlights recent work and current knowledge on the application of native hAM, and/or production of hAM-based tissue-engineered products to create scaffolds mimicking the structure of the native membrane to enhance the hAM performance. Moreover, an overview is presented on the available (cryo) preservation techniques for storage of native hAM and tissue-engineered products that are necessary to maintain biological functions such as angiogenesis, anti-inflammation, antifibrotic and antibacterial activity.

Repertoire characterization and validation of gB-specific human IgGs directly cloned from humanized mice vaccinated with dendritic cells and protected against HCMV

Human cytomegalovirus (HCMV) causes serious complications to immune compromised hosts. Dendritic cells (iDCgB) expressing granulocyte-macrophage colony-stimulating factor, interferon-alpha and HCMV-gB were developed to promote de novo antiviral adaptive responses. Mice reconstituted with a human immune system (HIS) were immunized with iDCgB and challenged with HCMV, resulting into 93% protection. Immunization stimulated the expansion of functional effector memory CD8⁺ and CD4⁺ T cells recognizing gB. Machine learning analyses confirmed bone marrow T/CD4⁺, liver B/IgA⁺ and spleen B/IgG⁺ cells as predictive biomarkers of immunization (≈87% accuracy). CD8⁺ and CD4⁺ T cell responses against gB were validated. Splenic gB-binding IgM^-/IgG⁺ B cells were sorted and analyzed at a single cell level. iDCgB immunizations elicited human-like IgG responses with a broad usage of various IgG heavy chain V gene segments harboring variable levels of somatic hypermutation. From this search, two gB-binding human monoclonal IgGs were generated that neutralized HCMV infection in vitro. Passive immunization with these antibodies provided proof-of-concept evidence of protection against HCMV infection. This HIS/HCMV in vivo model system supported the validation of novel active and passive immune therapies for future clinical translation.

Human cytomegalovirus (HCMV) is a ubiquitous pathogen. As long as the immune system is functional, T and B cells can control HCMV. Yet, for patients who have debilitated immune functions, HCMV infections and reactivations cause major complications. Vaccines or antibodies to prevent or treat HCMV are not yet approved. Novel animal models for testing new immunization approaches are emerging and are important tools to identify biomedical products with a reasonable chance to work in patients. Here, we used a model based on mice transplanted with human immune cells and infected with a traceable HCMV. We tested a cell vaccine (iDCgB) carrying gB, a potent HCMV antigen. The model showed that iDCgB halted the HCMV infection in more than 90% of the mice. We found that antibodies were key players mediating protection. Using state-of-the-art methods, we were able to use the sequences of the human antibodies generated in the mice to construct and produce monoclonal antibodies in the laboratory. Proof-of-concept experiments indicated that administration of these monoclonal antibodies into mice protected them against HCMV infection. In summary, this humanized mouse model was useful to test a vaccine and to generate and test novel antibodies that can be further developed for human use.

Rhodococcus equi infection as inaugural manifestation of idiopathic CD4+ lymphopenia: A rare entity and a therapeutic challenge

We report a case of disseminated infection by Rhodococcus equi as the inaugural manifestation of idiopathic T-CD4⁺ lymphopenia. We aim to demonstrate our diagnostic and therapeutic approach and focus on the major dilemmas arising from the lack of scientific evidence regarding best clinical practice of this infection in humans.

SAT0556 FINE STRUCTURE ANALYSIS OF THE INTER-RELATION BETWEEN TOPHUS DEPOSITION AND BONE LESIONS IN GOUT USING A COMBINATION OF DUAL ENERGY AND HIGH-RESOLUTION CT

Background:

Deposition of uric acid crystals cause an inflammatory reaction, which can lead to structural bone changes, if such deposits form adjacent to cortical bone [1, 2]. Both erosions and bony spurs can form in conjunction with tophus deposition. The exact spatial inter-relation between tophi and structural bone lesions in humans in vivo is not fully characterized.

Objectives:

To spatially relate structural bone changes (erosions, osteophytes) to the deposition of monosodium urate crystals in the first metatarsophalangeal (MTP1) joint in patients with tophaceous gout.

Methods:

Tophaceous gout patients with clinically detected tophi at the MTP1 joint underwent simultaneous dual energy computed tomography (DECT) and high-resolution peripheral quantitative computed tomography (HR-pQCT) of the feet. Tophi detected by DECT and erosions and osteophytes detected by HR-pQCT were overlayed to define their exact anatomical relation. Furthermore, feet of sex- and age-matched healthy controls (HC) were scanned to define the normal architecture of the MTP1 joint.

Results:

Gout patients (N=20) had significantly higher numbers (5 (0–17 vs. 1 (1– 2)) and volumes (45.32 mm3(7.26–550.32) vs. 0.82 mm3(0.15–21.8)) of bone erosions as well as significantly higher numbers (10.5 (0-26) vs. 1 (0-10)) and sizes of osteophytes (4.93 mm (0.77-7.19 mm vs. 0.93 mm (0.05-7.61 mm))than healthy controls (N=20). Erosions were in direct spatial relation to bone erosions, while osteophytic responses were more widespread and affected bone regions on the MTP1, which were not directly adjacent to tophi. Median tophus volume detected by DECT (0.12 mm3(0.01–2.53)) was associated with the total volume of erosions (r=0.597, p=0.005).

Conclusion:

This study demonstrates that bone changes in gout are substantial and not only include erosions but also widespread architectural bone remodeling associated osteophyte formation. While there is a direct spatial relation between tophi and bone erosions the anabolic bone responses in gout are more widespread.

References:

[1]Dalbeth, N. et al. Ann Rheum Dis. 2015 Jun;74(6):1030-6.

[2]Dalbeth, N. et al. Arthritis Res Ther. 2012; 14(4): R165.

Data are based on high-resolution peripheral quantitative computed tomography (HR-pQCT) of metatarsophalangeal joints I in gout patients (grey boxplots) and healthy controls (white boxplots). (A) number of bone erosions, (B) volume of bone erosions, (C) number of osteophytes and (D) size of osteophytes. Data are shown as medians and inter-quartile ranges (boxes).

Distribution of (A) tophi based on dual-energy computed tomography (DECT) as well as (B) bone erosions and (C) osteophytes based on high-resolution peripheral quantitative computed tomography (HR-pQCT) of metatarsophalangeal (MTP) I head in gout patients. Data are shown for the different regions of the MTPI head including the plantar, medial, dorsal and lateral region of the metatarsal head, as well as the medial and lateral sesamoid bones. Data indicate percentage of patients with tophi, erosions and osteophytes in respective region.

Disclosure of Interests:

Sara Bayat Speakers bureau: Novartis, David Simon Grant/research support from: Else Kröner-Memorial Scholarship, Novartis, Consultant of: Novartis, Lilly, Caroline Pecherstorfer: None declared, Hanna Ellmann: None declared, Camille Figueiredo: None declared, Matthias Englbrecht: None declared, Axel Hueber Grant/research support from: Novartis, Lilly, Pfizer, EIT Health, EU-IMI, DFG, Universität Erlangen (EFI), Consultant of: Abbvie, BMS, Celgene, Gilead, GSK, Lilly, Novartis, Speakers bureau: GSK, Lilly, Novartis, Arnd Kleyer Consultant of: Lilly, Gilead, Novartis,Abbvie, Speakers bureau: Novartis, Lilly, Jürgen Rech Consultant of: BMS, Celgene, Novartis, Roche, Chugai, Speakers bureau: AbbVie, Biogen, BMS, Celgene, MSD, Novartis, Roche, Chugai, Pfizer, Lilly, Georg Schett Speakers bureau: AbbVie, BMS, Celgene, Janssen, Eli Lilly, Novartis, Roche and UCB

Triple (GGTA1, CMAH, B2M) modified pigs expressing an SLA class Ilow phenotype-Effects on immune status and susceptibility to human immune responses

Porcine xenografts lacking swine leukocyte antigen (SLA) class I are thought to be protected from human T cell responses. We have previously shown that SLA class I deficiency can be achieved in pigs by CRISPR/Cas9-mediated deletion of β₂ -microglobulin (B2M). Here, we characterized another line of genetically modified pigs in which targeting of the B2M locus did not result in complete absence of B2M and SLA class I but rather in significantly reduced expression levels of both molecules. Residual SLA class I was functionally inert, because no proper differentiation of the CD8⁺ T cell subset was observed in B2M^low pigs. Cells from B2M^low pigs were less capable in triggering proliferation of human peripheral blood mononuclear cells in vitro, which was mainly due to the nonresponsiveness of CD8⁺ T cells. Nevertheless, cytotoxic effector cells developing from unaffected cell populations (eg, CD4⁺ T cells, natural killer cells) lysed targets from both SLA class I⁺ wildtype and SLA class I^low pigs with similar efficiency. These data indicate that the absence of SLA class I is an effective approach to prevent the activation of human CD8⁺ T cells during the induction phase of an anti-xenograft response. However, cytotoxic activity of cells during the effector phase cannot be controlled by this approach.

Genetic Engineering of the Kidney to Permanently Silence MHC Transcripts During ex vivo Organ Perfusion

Organ gene therapy represents a promising tool to correct diseases or improve graft survival after transplantation. Polymorphic variation of the major histocompatibility complex (MHC) antigens remains a major obstacle to long-term graft survival after transplantation. Previously, we demonstrated that MHC-silenced cells are protected against allogeneic immune responses. We also showed the feasibility to silence MHC in the lung. Here, we aimed at the genetic engineering of the kidney toward permanent silencing of MHC antigens in a rat model. We constructed a sub-normothermic ex vivo perfusion system to deliver lentiviral vectors encoding shRNAs targeting β2-microglobulin and the class II transactivator to the kidney. In addition, the vector contained the sequence for a secreted nanoluciferase. After kidney transplantation (ktx), we detected bioluminescence in the plasma and urine of recipients of an engineered kidney during the 6 weeks of post-transplant monitoring, indicating a stable transgene expression. Remarkably, transcript levels of β2-microglobulin and the class II transactivator were decreased by 70% in kidneys expressing specific shRNAs. Kidney genetic modification did not cause additional cell death compared to control kidneys after machine perfusion. Nevertheless, cytokine secretion signatures were altered during perfusion with lentiviral vectors as revealed by an increase in the secretion of IL-10, MIP-1α, MIP-2, IP-10, and EGF and a decrease in the levels of IL-12, IL-17, MCP-1, and IFN-γ. Biodistribution assays indicate that the localization of the vector was restricted to the graft. This study shows the potential to generate immunologically invisible kidneys showing great promise to support graft survival after transplantation and may contribute to reduce the burden of immunosuppression.

Implementation process of social prescribing to improve primary care patients’ health and well-being

Key messages

The social prescribing intervention has been effective in tackling multiple social determinants of health. Intervention evaluation is being key to identify facilitators and opportunities for scale up.

The ageing joint-standard age- and sex-related values of bone erosions and osteophytes in the hand joints of healthy individuals

OBJECTIVE

To analyze the age-related changes of the physiological hand joint architecture.

METHOD

To address this concept, healthy individuals (each 10 women and 10 men in six different age decades spanning from 21 to 80 years) were recruited through a field campaign, investigated for the absence of rheumatic diseases and other comorbidities and received high-resolution quantitative computed tomography (HR-pQCT) examination of the hand joints. Number and extent of erosions and osteophytes were quantified across the ages and different sexes.

RESULTS

Bone erosions [median (Q1-Q3), 1 (0-2)] and osteophytes [2 (1-4)] were found in healthy women and men with no significant sex differences. Structural changes however accumulated with age: the overall incidence rate ratio (IRR) for the number of erosions and osteophytes per age were 1.04 (95% CI: erosions 1.03-1.06; osteophytes: 1.03-1.05). This means a 4% increase in the number of erosions and osteophytes per year. Using third decade as reference, healthy individuals in the age decades from 50 years had higher IRR for erosion numbers (sixth, seventh, eigth decade: 4.87 (2.20-11.75), 6.81 (3.08-16.46) and 6.92 (3.11-16.79)) compared to younger subjects (fourth, fifth decade: 1.80 (0.69-4.87), 1.53 (0.59-4.10)). The IRRs of osteophytes also indicate a gradual increase after the fifth decade, with IRRs of 2.32 (1.32-4.17), 4.17 (2.38-7.49) and 6.86 (3.97-12.20) for the sixth, seventh and eigth decades, respectively.

CONCLUSIONS

Structural changes in the hand joints of healthy individuals are age dependent. While being rare under 50 years of age, erosions and osteophytes accumulate above the age of 50, suggesting that the threshold between "normal" and "pathological" is shifted with the increase of age.

HLA class II antibodies induce necrotic cell death in human endothelial cells via a lysosomal membrane permeabilization-mediated pathway

Antibody-mediated rejection (AMR) is the major cause of allograft loss after solid organ transplantation. Circulating donor-specific antibodies against human leukocyte antigen (HLA), in particular HLA class II antibodies are critical for the pathogenesis of AMR via interactions with endothelial cells (ECs). To investigate the effects of HLA class II antibody ligation to the graft endothelium, a model of HLA-DR antibody-dependent stimulation was utilized in primary human ECs. Antibody ligation of HLA class II molecules in interferon-γ-treated ECs caused necrotic cell death without complement via a pathway that was independent of apoptosis and necroptosis. HLA-DR-mediated cell death was blocked by specific neutralization of antibody ligation with recombinant HLA class II protein and by lentiviral knockdown of HLA-DR in ECs. Importantly, HLA class II-mediated cytotoxicity was also induced by relevant native allele-specific antibodies from human allosera. Necrosis of ECs in response to HLA-DR ligation was mediated via hyperactivation of lysosomes, lysosomal membrane permeabilization (LMP), and release of cathepsins. Notably, LMP was caused by reorganization of the actin cytoskeleton. This was indicated by the finding that LMP and actin stress fiber formation by HLA-DR antibodies were both downregulated by the actin polymerization inhibitor cytochalasin D and inhibition of Rho GTPases, respectively. Finally, HLA-DR-dependent actin stress fiber formation and LMP led to mitochondrial stress, which was revealed by decreased mitochondrial membrane potential and generation of reactive oxygen species in ECs. Taken together, ligation of HLA class II antibodies to ECs induces necrotic cell death independent of apoptosis and necroptosis via a LMP-mediated pathway. These findings may enable novel therapeutic approaches for the treatment of AMR in solid organ transplantation.

Impact of 5-week high-intensity interval training on indices of cardio metabolic health in men

PURPOSE

To compare the acute and chronic effects of high-intensity intermittent training (HIIT) and moderate-intensity continuous training (MICT) on indices of cardio-metabolic health: (HDL-c, total cholesterol, triglycerides, heart ratio, and phase angle/PhA) in physically active men.

METHODS

Twenty active men were randomly allocated to HIIT (n = 10), or MICT (n = 10) for 5 weeks, three times per week. HIIT consisted of running 5 km with 1-min at 100% of maximal aerobic speed interspersed by 1-min passive recovery while subjects in MICT group ran continuously the same 5 km at 70% of maximal aerobic speed. Blood samples were collected at different moments during the first and last exercise session. Before and after 5 weeks of both exercise training protocols, heart ratio (during exercise session) and PhA were measured pre and post-exercise training.

RESULTS

Fasting HDL-c levels did not change after 5 weeks of HIIT or MICT. Perceptual variation of HDL pre and post training (fed state) tended to differ between HIIT and MICT (p = 0.09). All lipoproteins parameters (HDL-c, total cholesterol, triglycerides and non-HDL) were increased in post-acute exercise session compared to pre-exercise during the first and last training session, these being observed after both training protocols. PhA and heart rate measured at different times during the first and last training session were not affected in both training protocols.

CONCLUSION

These results indicate that HIIT and MICT modify the post-exercise lipoprotein profile acutely. On the other hand, only HIIT tended to increase HDL-c levels chronically.

Bioreactor-based mass production of human iPSC-derived macrophages enables immunotherapies against bacterial airway infections

The increasing number of severe infections with multi-drug-resistant pathogens worldwide highlights the need for alternative treatment options. Given the pivotal role of phagocytes and especially alveolar macrophages in pulmonary immunity, we introduce a new, cell-based treatment strategy to target bacterial airway infections. Here we show that the mass production of therapeutic phagocytes from induced pluripotent stem cells (iPSC) in industry-compatible, stirred-tank bioreactors is feasible. Bioreactor-derived iPSC-macrophages (iPSC-Mac) represent a highly pure population of CD45⁺CD11b⁺CD14⁺CD163⁺ cells, and share important phenotypic, functional and transcriptional hallmarks with professional phagocytes, however with a distinct transcriptome signature similar to primitive macrophages. Most importantly, bioreactor-derived iPSC-Mac rescue mice from Pseudomonas aeruginosa-mediated acute infections of the lower respiratory tract within 4-8 h post intra-pulmonary transplantation and reduce bacterial load. Generation of specific immune-cells from iPSC-sources in scalable stirred-tank bioreactors can extend the field of immunotherapy towards bacterial infections, and may allow for further innovative cell-based treatment strategies.

Pulmonary infections constitute a substantial health problem worldwide. Here the authors show that phagocytes similar to primitive macrophages can be generated from human induced pluripotent stem cells, by the use of industry-compatible, stirred-tank bioreactors, and applied as a cell-based therapy to treat acute bacterial infections in mice.

Signatures of T and B Cell Development, Functional Responses and PD-1 Upregulation After HCMV Latent Infections and Reactivations in Nod.Rag.Gamma Mice Humanized With Cord Blood CD34+ Cells

Human cytomegalovirus (HCMV) latency is typically harmless but reactivation can be largely detrimental to immune compromised hosts. We modeled latency and reactivation using a traceable HCMV laboratory strain expressing the Gaussia luciferase reporter gene (HCMV/GLuc) in order to interrogate the viral modulatory effects on the human adaptive immunity. Humanized mice with long-term (more than 17 weeks) steady human T and B cell immune reconstitutions were infected with HCMV/GLuc and 7 weeks later were further treated with granulocyte-colony stimulating factor (G-CSF) to induce viral reactivations. Whole body bio-luminescence imaging analyses clearly differentiated mice with latent viral infections vs. reactivations. Foci of vigorous viral reactivations were detectable in liver, lymph nodes and salivary glands. The number of viral genome copies in various tissues increased upon reactivations and were detectable in sorted human CD14⁺, CD169⁺, and CD34⁺ cells. Compared with non-infected controls, mice after infections and reactivations showed higher thymopoiesis, systemic expansion of Th, CTL, Treg, and Tfh cells and functional antiviral T cell responses. Latent infections promoted vast development of memory CD4⁺ T cells while reactivations triggered a shift toward effector T cells expressing PD-1. Further, reactivations prompted a marked development of B cells, maturation of IgG⁺ plasma cells, and HCMV-specific antibody responses. Multivariate statistical methods were employed using T and B cell immune phenotypic profiles obtained with cells from several tissues of individual mice. The data was used to identify combinations of markers that could predict an HCMV infection vs. reactivation status. In spleen, but not in lymph nodes, higher frequencies of effector CD4⁺ T cells expressing PD-1 were among the factors most suited to distinguish HCMV reactivations from infections. These results suggest a shift from a T cell dominated immune response during latent infections toward an exhausted T cell phenotype and active humoral immune response upon reactivations. In sum, this novel in vivo humanized model combined with advanced analyses highlights a dynamic system clearly specifying the immunological spatial signatures of HCMV latency and reactivations. These signatures can be merged as predictive biomarker clusters that can be applied in the clinical translation of new therapies for the control of HCMV reactivation.

Immunoengineering of the Vascular Endothelium to Silence MHC Expression During Normothermic Ex Vivo Lung Perfusion

Disparities at the major histocompatibility complex (MHC) antigens and associated minor antigens trigger harmful immune responses, leading to graft rejection after transplantation. We showed that MHC-silenced cells and tissues are efficiently protected against rejection. In complex vascularized organs, the endothelium is the major interface between donor and recipient. This study therefore aimed to reduce the immunogenicity of the lung by silencing MHC expression on the endothelium. In porcine lungs, short-hairpin RNAs targeting beta-2-microglobulin and class II-transactivator transcripts were delivered by lentiviral vectors during normothermic ex vivo perfusion to silence swine leukocyte antigen (SLA) I and II expression permanently. The results demonstrated the feasibility of genetically engineering all lung regions, achieving a targeted silencing effect for SLA I and II of 67% and 52%, respectively, without affecting cell viability or tissue integrity. This decrease in immunogenicity carries the potential to generate immunologically invisible organs to counteract the burden of rejection and immunosuppression.

Characterization of induced pluripotent stem cell-derived megakaryocyte lysates for potential regenerative applications

Recently, platelet‐derived growth factors present in lysates became an extreme interest in the field of regenerative medicine such as in wound healing and as substitutes to foetal bovine serum in xeno‐free cell culture systems. However, the generation of such platelet lysates completely depends on the availability of platelet donors. In this study, the possibility to use in vitro‐generated megakaryocytes derived from induced pluripotent stem cells (iPSCs) as a cell source for typical platelet growth factors was investigated. Therefore, the presence and levels of those factors were characterized in in vitro‐produced megakaryocytes. In comparison with platelets, in vitro‐generated megakaryocytes showed a multifold increased content in transcript and protein levels of typical platelet growth factors including platelet‐derived growth factors (PDGFs), transforming growth factor (TGF)‐1β, vascular endothelial cell factor (VEGF)‐A, epidermal growth factor (EGF), insulin‐like growth factor (IGF)‐1 and tissue factor (TF). Hence, iPSC‐derived megakaryocytes may serve as an efficient cell source for a donor‐independent generation of growth factor‐rich lysates with a broad application potential in innovative cell culture systems and regenerative therapies.

Hepatocyte-induced CD4+ T cell alloresponse is associated with major histocompatibility complex class II up-regulation on hepatocytes and suppressible by regulatory T cells

Hepatocyte transplantation is a promising therapeutic approach for various liver diseases. Despite the liver's tolerogenic potential, early immune-mediated loss of transplanted cells is observed, and longterm acceptance has not been achieved yet. Patients deemed tolerant after liver transplantation presented an increased frequency of regulatory T cells (Tregs), which therefore also might enable reduction of posttransplant cell loss and enhance longterm allograft acceptance. We hence characterized hepatocyte-induced immune reactions and evaluated the immunomodulatory potential of Tregs applying mixed lymphocyte cultures and mixed lymphocyte hepatocyte cultures. These were set up using peripheral blood mononuclear cells and primary human hepatocytes, respectively. Polyclonally expanded CD4⁺ CD25^high CD127^low Tregs were added to cocultures in single-/trans-well setups with/without supplementation of anti-interferon γ (IFNγ) antibodies. Hepatocyte-induced alloresponses were then analyzed by multicolor flow cytometry. Measurements indicated that T cell response upon stimulation was associated with IFNγ-induced major histocompatibility complex (MHC) class II up-regulation on hepatocytes and mediated by CD4⁺ T cells. An indirect route of antigen presentation could be ruled out by use of fragmented hepatocytes and culture supernatants of hepatocytes. Allospecific proliferation was accompanied by inflammatory cytokine secretion. CD8⁺ T cells showed early up-regulation of CD69 despite lack of cell proliferation in the course of coculture. Supplementation of Tregs effectively abrogated hepatocyte-induced alloresponses and was primarily cell contact dependent. In conclusion, human hepatocytes induce a CD4⁺ T cell alloresponse in vitro, which is associated with MHC class II up-regulation on hepatocytes and is susceptible to suppression by Tregs. Liver Transplantation 24 407-419 2018 AASLD.

Multidimensional Analysis Integrating Human T-Cell Signatures in Lymphatic Tissues with Sex of Humanized Mice for Prediction of Responses after Dendritic Cell Immunization

Mice transplanted with human cord blood-derived hematopoietic stem cells (HSCs) became a powerful experimental tool for studying the heterogeneity of human immune reconstitution and immune responses in vivo. Yet, analyses of human T cell maturation in humanized models have been hampered by an overall low immune reactivity and lack of methods to define predictive markers of responsiveness. Long-lived human lentiviral induced dendritic cells expressing the cytomegalovirus pp65 protein (iDCpp65) promoted the development of pp65-specific human CD8⁺ T cell responses in NOD.Cg-Rag1^tm1Mom-Il2rγ^tm1Wj humanized mice through the presentation of immune-dominant antigenic epitopes (signal 1), expression of co-stimulatory molecules (signal 2), and inflammatory cytokines (signal 3). We exploited this validated system to evaluate the effects of mouse sex in the dynamics of T cell homing and maturation status in thymus, blood, bone marrow, spleen, and lymph nodes. Statistical analyses of cell relative frequencies and absolute numbers demonstrated higher CD8⁺ memory T cell reactivity in spleen and lymph nodes of immunized female mice. In order to understand to which extent the multidimensional relation between organ-specific markers predicted the immunization status, the immunophenotypic profiles of individual mice were used to train an artificial neural network designed to discriminate immunized and non-immunized mice. The highest accuracy of immune reactivity prediction could be obtained from lymph node markers of female mice (77.3%). Principal component analyses further identified clusters of markers best suited to describe the heterogeneity of immunization responses in vivo. A correlation analysis of these markers reflected a tissue-specific impact of immunization. This allowed for an organ-resolved characterization of the immunization status of individual mice based on the identified set of markers. This new modality of multidimensional analyses can be used as a framework for defining minimal but predictive signatures of human immune responses in mice and suggests critical markers to characterize responses to immunization after HSC transplantation.

Towards the Manufacture of Megakaryocytes and Platelets for Clinical Application

Platelet transfusions are used in standard clinical practice to prevent hemorrhage in patients suffering from thrombocytopenia or platelet dysfunctions. Recently, a constant rise on the demand of platelets for transfusion has been registered. This may be associated with several factors including demographic changes, population aging as well as incidence and prevalence of hematological diseases. In addition, platelet-regenerative properties have been started to be exploited in different areas such as tissue remodeling and anti-cancer therapies. These new applications are also expected to increase the future demand on platelets. Thus, in vitro generated platelets may constitute a highly desirable alternative to meet the rising demand on platelets. Several factors have been considered in the road trip of producing in vitro megakaryocytes and platelets for clinical application. From selection of the cell source, differentiation protocols and culture conditions to the design of optimal bioreactors, several strategies have been proposed to maximize production yields while preserving functionality. This review summarizes new advances in megakaryocyte and platelet differentiation and their production upscaling.

Human Effector Memory T Helper Cells Engage with Mouse Macrophages and Cause Graft-versus-Host-Like Pathology in Skin of Humanized Mice Used in a Nonclinical Immunization Study

Humanized mice engrafted with human hematopoietic stem cells and developing functional human T-cell adaptive responses are in critical demand to test human-specific therapeutics. We previously showed that humanized mice immunized with long-lived induced-dendritic cells loaded with the pp65 viral antigen (iDCpp65) exhibited a faster development and maturation of T cells. Herein, we evaluated these effects in a long-term (36 weeks) nonclinical model using two stem cell donors to assess efficacy and safety. Relative to baseline, iDCpp65 immunization boosted the output of effector memory CD4⁺ T cells in peripheral blood and lymph nodes. No weight loss, human malignancies, or systemic graft-versus-host (GVH) disease were observed. However, for one reconstitution cohort, some mice immunized with iDCpp65 showed GVH-like signs on the skin. Histopathology analyses of the inflamed skin revealed intrafollicular and perifollicular human CD4⁺ cells near F4/80⁺ mouse macrophages around hair follicles. In spleen, CD4⁺ cells formed large clusters surrounded by mouse macrophages. In plasma, high levels of human T helper 2-type inflammatory cytokines were detectable, which activated in vitro the STAT5 pathway of murine macrophages. Despite this inflammatory pattern, human CD8⁺ T cells from mice with GVH reacted against the pp65 antigen in vitro. These results uncover a dynamic cross-species interaction between human memory T cells and mouse macrophages in the skin and lymphatic tissues of humanized mice.

Discovery of immunodominant T-cell epitopes reveals penton protein as a second immunodominant target in human adenovirus infection

Background

Human adenovirus (HAdV) infections remain a significant cause of morbidity and mortality after hematopoietic stem cell transplantation (HSCT). Efficient antiviral T-cell responses are necessary to clear infection, which is hampered by delayed immune reconstitution and medical immunosuppression after HSCT. Protective immunity may be conferred by adoptive transfer of HAdV-specific T cells. For identification of patients at risk and monitoring of treatment responses diligent assessment of anti-HAdV cellular immune responses is crucial. The HAdV-derived protein hexon has been recognized as a major immunodominant target across HAdV species. We aimed at identifying further targets of protective anti-HAdV immune response and characterizing immunogenic epitopes.

Methods

Nineteen candidate nonamers from hexon and penton proteins were identified by epitope binding prediction. Peptides were synthesized and tested for in vivo immunogenicity by screening peripheral blood mononuclear cells from healthy volunteers (n = 64) and HAdV-infected stem cell recipients (n = 26) for memory T cells recognizing the candidate epitopes in the context of most common HLA alleles.

Results

Functional CD8⁺ T cells recognizing seven epitopes were identified, among them four penton-derived and two hexon-derived peptides. The HLA-A*01-restricted penton-derived peptide STDVASLNY (A01Penton_STDV) and HLA-A*02-restricted hexon-derived peptide TLLYVLFEV (A02Hexon_TLLY) were recognized by more than half of the persons carrying the respective HLA-type.

Conclusions

Thus, the HAdV-derived penton protein is a novel major target of the anti-HAdV immune response. Identification of new immunodominant epitopes will facilitate and broaden immune assessment strategies to identify patients suitable for T-cell transfer. Knowledge of additional target structures may increase T-cell recovery in manufacturing processes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-1042-2) contains supplementary material, which is available to authorized users.