Project description:Nasal administration of anti-CD3 monoclonal antibody (Foralumab) modulates effector CD8+ T cell function and induces a regulatory response in T cells in human subjects
Project description:Patients diagnosed with coronavirus disease 2019 (COVID-19) mostly become critically ill around the time of activation of the adaptive immune response. Here, we provide evidence that antibodies play a role in the worsening of disease at the time of seroconversion. We show that early phase severe acute respiratory distress syndrome coronavirus 2 (SARS-CoV-2) spike protein-specific IgG in serum of critically ill COVID-19 patients induces hyper-inflammatory responses by human alveolar macrophages. We identified that this excessive inflammatory response is dependent on two antibody features that are specific for patients with severe COVID-19. First, inflammation is driven by high titers of anti-spike IgG, a hallmark of severe disease. Second, we found that anti-spike IgG from patients with severe COVID-19 is intrinsically more pro-inflammatory because of different glycosylation, particularly low fucosylation, of the Fc tail. Notably, low anti-spike IgG fucosylation normalized in a few weeks after initial infection with SARS-CoV-2, indicating that the increased antibody-dependent inflammation mainly occurs at the time of seroconversion. We identified Fcγ Receptor (FcγR) IIa and FcγRIII as the two primary IgG receptors that are responsible for the induction of key COVID-19-associated cytokines such as interleukin-6 and tumor necrosis factor. In addition, we show that anti-spike IgG-activated macrophages can subsequently break pulmonary endothelial barrier integrity and induce microvascular thrombosis in vitro. Finally, we demonstrate that the hyper-inflammatory response induced by anti-spike IgG can be specifically counteracted by fostamatinib, an FDA- and EMA-approved therapeutic small molecule inhibitor of the kinase, Syk.
Project description:Human peripheral blood mononuclear cells were purified from healthy volunteers' blood and were cultured in the presence of the monoclonal antibody OKT3 or a recombinant fragment of humanized anti-CD3. After 72 hours, CD3+ T cells were isolated by negative selection using beads.
Project description:Nasal administration of anti-CD3 monoclonal antibody (Foralumab) modulates effector CD8+ T cell function and induces a regulatory response in T cells in human subjects
Project description:A dysregulated immune response against the SARS-CoV-2 virus plays a critical role in severe COVID-19. However, the molecular and cellular mechanisms by which the virus causes lethal immunopathology are poorly understood. Here, we utilize multi-omics single-cell analysis to probe dynamic immune responses in patients with stable or progressive manifestations of COVID-19, and assess the effects of tocilizumab, an anti-IL-6 receptor monoclonal antibody. Coordinated profiling of gene expression and cell lineage protein markers reveals a prominent type-1 interferon response across all immune cells, especially in progressive patients. An anti-inflammatory signature in monocytes and a pre-exhaustion phenotype in activated T cells are hallmarks of progressive disease. Single-cell T and B cell receptor repertoire analysis reveal a skewed clonal distribution of CD8 T cells and a primary B cell response with possible contribution from memory B cells. Our in-depth immune profiling reveals dyssynchrony of the innate and adaptive immune interaction in progressive COVID-19, which may contribute to delayed virus clearance and has implications for therapeutic intervention.
Project description:A dysregulated immune response against the SARS-CoV-2 virus plays a critical role in severe COVID-19. However, the molecular and cellular mechanisms by which the virus causes lethal immunopathology are poorly understood. Here, we utilize multi-omics single-cell analysis to probe dynamic immune responses in patients with stable or progressive manifestations of COVID-19, and assess the effects of tocilizumab, an anti-IL-6 receptor monoclonal antibody. Coordinated profiling of gene expression and cell lineage protein markers reveals a prominent type-1 interferon response across all immune cells, especially in progressive patients. An anti-inflammatory signature in monocytes and a pre-exhaustion phenotype in activated T cells are hallmarks of progressive disease. Single-cell T and B cell receptor repertoire analysis reveal a skewed clonal distribution of CD8 T cells and a primary B cell response with possible contribution from memory B cells. Our in-depth immune profiling reveals dyssynchrony of the innate and adaptive immune interaction in progressive COVID-19, which may contribute to delayed virus clearance and has implications for therapeutic intervention.
Project description:The tolerogenic anti-CD3 monoclonal antibodies (anti-CD3) are promising compounds for the treatment of type 1 diabetes (T1D). Anti-CD3 administration induces transient T-cell depletion both in preclinical and in clinical studies. Notably, said depletion mainly affects CD4+ but not CD8+ T cells. Moreover, T1D reversal in preclinical models is accompanied by the selective expansion of CD4+FOXP3+ T regulatory (Treg) cells, which are fundamental for the long-term maintenance of anti-CD3-mediated tolerance. The mechanisms that lead to this immune-shaping by affecting mainly CD4+ T effector cells while sparing CD4+FOXP3+ Treg cells have still to be fully elucidated. This study shows that CD3 expression levels differ from one T-cell subset to another. CD4+FOXP3- T cells contain higher amounts of CD3 molecules than do CD4+FOXP3+ and CD8+ T cells both in mice and in humans. Said differences may explain the anti-CD3-mediated immune resetting that occurs in vivo after anti-CD3 administration in mice. In addition, transcriptome analysis demonstrates that CD4+FoxP3+ Treg cells are significantly less responsive than CD4+FoxP3- T cells to anti-CD3 treatment at molecular levels. Thus, heterogeneity in CD3 expression likely confers the various T-cell subsets differing susceptibility to in vivo tolerogenic anti-CD3-mediated modulation. This data sheds new light on the molecular mechanism that underlies anti-CD3-mediated immune resetting, and thus may open new opportunities to improve this promising treatment.
Project description:COVID-19 patients frequently develop neurological symptoms, but the biological underpinnings of these phenomena are unknown. Through single cell RNA-seq and cytokine analyses of CSF and blood from COVID-19 patients with neurological symptoms, we find compartmentalized, CNS specific T cell activation and B cell responses. All COVID-19 cases had CSF anti-SARS-CoV-2 antibodies whose target epitopes diverged from serum antibodies. In an animal model, we find that intrathecal SARS-CoV-2 antibodies are found only during brain infection, and are not elicited by pulmonary infection. We produced CSF-derived monoclonal antibodies from a COVID-19 patient, and find that these mAbs target both anti-viral and anti-neural antigens including one mAb that reacted to both spike protein and neural tissue. Overall, CSF IgG from 5/7 patients contains anti-neural reactivity. This immune survey reveals evidence of a compartmentalized immune response in the CNS of COVID-19 patients and suggests a role for autoimmunity in neurologic sequelae of COVID-19.
Project description:COVID-19 patients frequently develop neurological symptoms, but the biological underpinnings of these phenomena are unknown. Through single cell RNA-seq and cytokine analyses of CSF and blood from COVID-19 patients with neurological symptoms, we find compartmentalized, CNS specific T cell activation and B cell responses. All COVID-19 cases had CSF anti-SARS-CoV-2 antibodies whose target epitopes diverged from serum antibodies. In an animal model, we find that intrathecal SARS-CoV-2 antibodies are found only during brain infection, and are not elicited by pulmonary infection. We produced CSF-derived monoclonal antibodies from a COVID-19 patient, and find that these mAbs target both anti-viral and anti-neural antigens including one mAb that reacted to both spike protein and neural tissue. Overall, CSF IgG from 4/6 patients contains anti-neural reactivity. This immune survey reveals evidence of a compartmentalized immune response in the CNS of COVID-19 patients and suggests a role for autoimmunity in neurologic sequelae of COVID-19