Robust Distributed Control Protocols for Large Vehicular Platoons with Prescribed Transient and Steady State Performance

In this paper, we study the longitudinal control problem for a platoon of vehicles with unknown nonlinear dynamics under both the predecessor-following and the bidirectional control architectures. The proposed control protocols are fully distributed in the sense that each vehicle utilizes feedback from its relative position with respect to its preceding and following vehicles as well as its own velocity, which can all be easily obtained by onboard sensors. Moreover, no previous knowledge of model nonlinearities/disturbances is incorporated in the control design, enhancing in that way the robustness of the overall closed loop system against model imperfections. Additionally, certain designer-specified performance functions determine the transient and steady-state response, thus preventing connectivity breaks due to sensor limitations as well as inter-vehicular collisions. Finally, extensive simulation studies and a real-time experiment conducted with mobile robots clarify the proposed control protocols and verify their effectiveness.Comment: IEEE Transactions on Control Systems Technology, accepte

BCG Vaccination Induces Long-Term Functional Reprogramming of Human Neutrophils

The tuberculosis vaccine bacillus Calmette-Guérin (BCG) protects against some heterologous infections, probably via induction of non-specific innate immune memory in monocytes and natural killer (NK) cells, a process known as trained immunity. Recent studies have revealed that the induction of trained immunity is associated with a bias toward granulopoiesis in bone marrow hematopoietic progenitor cells, but it is unknown whether BCG vaccination also leads to functional reprogramming of mature neutrophils. Here, we show that BCG vaccination of healthy humans induces long-lasting changes in neutrophil phenotype, characterized by increased expression of activation markers and antimicrobial function. The enhanced function of human neutrophils persists for at least 3 months after vaccination and is associated with genome-wide epigenetic modifications in trimethylation at histone 3 lysine 4. Functional reprogramming of neutrophils by the induction of trained immunity might offer novel therapeutic strategies in clinical conditions that could benefit from modulation of neutrophil effector function

IL-1β Promotes TGF-β1 and IL-2 Dependent Foxp3 Expression in Regulatory T Cells

Earlier, we have shown that GM-CSF-exposed CD8α− DCs that express low levels of pro-inflammatory cytokines IL-12 and IL-1β can induce Foxp3+ Tregs leading to suppression of autoimmunity. Here, we examined the differential effects of IL-12 and IL-1β on Foxp3 expression in T cells when activated in the presence and absence of DCs. Exogenous IL-12 abolished, but IL-1β enhanced, the ability of GM-CSF-exposed tolerogenic DCs to promote Foxp3 expression. Pre-exposure of DCs to IL-1β and IL-12 had only a modest effect on Foxp3− expressing T cells; however, T cells activated in the absence of DCs but in the presence of IL-1β or IL-12 showed highly significant increase and decrease in Foxp3+ T cell frequencies respectively suggesting direct effects of these cytokines on T cells and a role for IL-1β in promoting Foxp3 expression. Importantly, purified CD4+CD25+ cells showed a significantly higher ability to maintain Foxp3 expression when activated in the presence of IL-1β. Further analyses showed that the ability of IL-1β to maintain Foxp3 expression in CD25+ T cells was dependent on TGF-β1 and IL-2 expression in Foxp3+Tregs and CD25− effectors T cells respectively. Exposure of CD4+CD25+ T cells to IL-1β enhanced their ability to suppress effector T cell response in vitro and ongoing experimental autoimmune thyroidits in vivo. These results show that IL-1β can help enhance/maintain Tregs, which may play an important role in maintaining peripheral tolerance during inflammation to prevent and/or suppress autoimmunity

Dna damage response in the adaptive arm of the immune system: Implications for autoimmunity

In complex environments, cells have developed molecular responses to confront threats against the genome and achieve the maintenance of genomic stability assuring the transfer of un-damaged DNA to their progeny. DNA damage response (DDR) mechanisms may be activated upon genotoxic or environmental agents, such as cytotoxic drugs or ultraviolet (UV) light, and during physiological processes requiring DNA transactions, to restore DNA alterations that may cause cellular malfunction and affect viability. In addition to the DDR, multicellular organisms have evolved specialized immune cells to respond and defend against infections. Both adaptive and innate immune cells are subjected to DDR processes, either as a prerequisite to the immune response, or as a result of random endogenous and exogenous insults. Aberrant DDR activities have been extensively studied in the immune cells of the innate arm, but not in adaptive immune cells. Here, we discuss how the aberrant DDR may lead to autoimmunity, with emphasis on the adaptive immune cells and the potential of therapeutic targeting. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Maturation of dendritic cells by necrotic thyrocytes facilitates induction of experimental autoimmune thyroiditis

Dendritic cell (DC) maturation is required for efficient presentation of autoantigens leading to autoimmunity. In this report, we have examined whether release of tissue antigens from necrotic thyroid epithelial cells can trigger DC maturation and initiation of a primary antiself response. DC were cocultured with either viable (VT/DC) or necrotic (NT/DC) thyrocytes, and their phenotypic and functional maturation as well as immunopathogenic potential were assessed. Significant up-regulation of surface MHC class II and costimulatory molecule expression was observed in NT/DC but not in VT/DC. This was correlated with a functional maturation of NT/DC, determined by IL-12 secretion. Challenge of CBA/J mice with NT/DC, but not with VT/DC, elicited thyroglobulin (Tg)-specific IgG as well as Tg-specific CD4+ T-cell responses and led to development of experimental autoimmune thyroiditis. These results support the view that thyroid epithelial cell necrosis may cause autoimmune thyroiditis via maturation of intrathyroidal DC

POS0413 COMPREHENSIVE IMMUNE PROFILING OF PERIPHERAL BLOOD IN PSORIATIC ARTHRITIS (PsA) PATIENTS: EXPANSION OF INTERMEDIATE MONOCYTES AND DECREASED T REG AND CD8 T CELLS

Background:Psoriatic arthritis (PsA) is a heterogeneous inflammatory arthritis that develops in a subset of patients with psoriasis. According to the current paradigm, cells of the innate and adaptive immunity interact with resident tissue fibroblasts mounting an inflammatory response via complex cytokine networks in the skin and joints in which type 1 and type 17 T cells play a dominant role. The abundance and relative contribution of other peripheral blood immune cells to disease pathogenesis as well the molecular signature of peripheral blood mononuclear cells and tissue fibroblasts remain ill defined.Objectives:To comprehensively characterize immune cell subsets driving inflammation in the peripheral blood of patients with active PsA and their impact on psoriatic skin fibroblasts.Methods:Peripheral blood was collected from PsA patients (n=31) and age-/sex-matched healthy individuals (HI) (n=9), after informed consent. Psoriatic skin biopsies were acquired from a subset of 5 patients and 3 HI. All patients fulfilled the CASPAR criteria for the diagnosis and displayed peripheral polyarthritis of moderate- to high-disease activity. Patients’ demographic and clinical data were recorded at time of sampling. Disease activity was assessed using the Disease Activity Index for Psoriatic arthritis (DAPSA) score. Skin psoriasis activity indices, enthesitis and dactylitis were also recorded. Peripheral blood mononuclear cells (PBMCs) were isolated by ficoll density gradient centrifugation. Flow cytometry was performed using a BD FACS-Aria-III and analyzed using FlowJo software. The antibody staining panel utilized aimed at the identification of the following immune cell subsets: Monocyte subsets (HLA-DR+ CD14+/- CD16+/-), Plasmacytoid dendritic cells (HLA- DR+ CD123+), T helper (CD4+), cytotoxic T (CD8+), regulatory T (CD4+ CD25+ CD127-) and B cells (CD19+). Statistical analyses were performed using GraphPad Prism software. Differences between groups were compared using unpaired T test for parametric data; Mann-Whitney and Kruskal Wallis tests for non-parametric data. The level of significance was set at P&lt;0.05.Results:9 males and 22 females PsA patients are included (mean age 50 years and the mean disease duration 19.2 years for skin disease and 5.9 years for arthritis). The mean DAPSA score was 43.4, suggestive of high disease activity, while 8 (26%) patients displayed clinical enthesitis at time of sampling. Flow cytometry analysis revealed aberrancies in peripheral blood immune cell populations. More specifically, PsA patients displayed a significant increase in intermediate monocyte subset (HLA-DR+ CD14+ CD16+) compared to HI with patients with clinical enthesitis demonstrating a more exaggerated expansion of intermediate monocytes compared to patients without enthesitis. A trend towards increased patrolling monocytes (HLA-DR+ CD14- CD16+) was also noted although this did not reach statistical significance. In contrast, both regulatory T cells and cytotoxic CD8+ T cells were significantly decreased probably due to their selective migration at the sites of inflammation. RNA-seq from whole blood and skin fibroblasts from affected skin are in progress.Conclusion:These data demonstrate significant expansion of intermediate monocytes -more pronounced in the enthesitis affected individuals- and decrease in T regulatory cells and T cytotoxic cells in PsA peripheral blood. Increased antigen presentation and co-stimulation mediated via intermediate monocytes in combination with their proangiogenic properties may contribute to disease pathogenesisReferences:[1]Veale, D. J. &amp; Fearon, U. The pathogenesis of psoriatic arthritis. The Lancet (2018) doi:10.1016/S0140-6736(18)30830-4.Disclosure of Interests:None declared</jats:sec