Neutralizing Complement C5a Protects Mice with Pneumococcal Pulmonary Sepsis.

Background: Community-acquired pneumonia and associated sepsis cause high mortality despite antibiotic treatment. Uncontrolled inflammatory host responses contribute to the unfavorable outcome by driving lung and extrapulmonary organ failure. The complement fragment C5a holds significant proinflammatory functions and is associated with tissue damage in various inflammatory conditions.

Increasing Tumor-Infiltrating T Cells through Inhibition of CXCL12 with NOX-A12 Synergizes with PD-1 Blockade.

Immune checkpoint inhibitors promote T cell-mediated killing of cancer cells; however, only a subset of patients benefit from the treatment. A possible reason for this limitation may be that the tumor microenvironment (TME) is immune privileged, which may exclude cytotoxic T cells from the vicinity of cancer cells. The chemokine CXCL12 is key to the TME-driven immune suppression.

Signaling of the Complement Cleavage Product Anaphylatoxin C5a Through C5aR (CD88) Contributes to Pharmacological Hematopoietic Stem Cell Mobilization.

Several mechanisms have been postulated for orchestrating the mobilization of hematopoietic stem/progenitor cells (HSPCs), and we previously proposed that activation of the complement cascade plays a crucial role in the initiation and execution of the egress of HSPCs from bone marrow (BM) into peripheral blood (PB). In support of this notion, we demonstrated that mice deficient in the mannan-binding lectin (MBL) pathway, which activates the proximal part of the complement cascade, as well as mice deficient in the fifth component of the complement cascade (C5), which is part of the distal part of the complement cascade, are poor mobilizers. To further narrow down on the exact mechanisms and the molecules involved, we performed studies in mice that do not express the receptor C5aR, which binds the C5 cleavage fragments, C5a and C5a.

A Combined PD-1/C5a Blockade Synergistically Protects against Lung Cancer Growth and Metastasis.

Disruption of the programmed cell death protein 1 (PD-1) pathway with immune checkpoint inhibitors represents a major breakthrough in the treatment of non-small cell lung cancer. We hypothesized that combined inhibition of C5a/C5aR1 and PD-1 signaling may have a synergistic antitumor effect. The RMP1-14 antibody was used to block PD-1, and an L-aptamer was used to inhibit signaling of complement C5a with its receptors.

Structural basis for the targeting of complement anaphylatoxin C5a using a mixed L-RNA/L-DNA aptamer.

L-Oligonucleotide aptamers (Spiegelmers) consist of non-natural L-configured nucleotides and are of particular therapeutic interest due to their high resistance to plasma nucleases. The anaphylatoxin C5a, a potent inflammatory mediator generated during complement activation that has been implicated with organ damage, can be efficiently targeted by Spiegelmers. Here, we present the first crystallographic structures of an active Spiegelmer, NOX-D20, bound to its physiological targets, mouse C5a and C5a-desArg.

Stereospecificity of oligonucleotide interactions revisited: no evidence for heterochiral hybridization and ribozyme/DNAzyme activity.

A major challenge for the application of RNA- or DNA-oligonucleotides in biotechnology and molecular medicine is their susceptibility to abundant nucleases. One intriguing possibility to tackle this problem is the use of mirror-image (l-)oligonucleotides. For aptamers, this concept has successfully been applied to even develop therapeutic agents, so-called Spiegelmers.

Identification and characterization of a mirror-image oligonucleotide that binds and neutralizes sphingosine 1-phosphate, a central mediator of angiogenesis.

The sphingolipid S1P (sphingosine 1-phosphate) is known to be involved in a number of pathophysiological conditions such as cancer, autoimmune diseases and fibrosis. It acts extracellularly through a set of five G-protein-coupled receptors, but its intracellular actions are also well documented. Employing in vitro selection techniques, we identified an L-aptamer (Spiegelmer®) to S1P designated NOX-S93.

IL-35-producing B cells are critical regulators of immunity during autoimmune and infectious diseases.

B lymphocytes have critical roles as positive and negative regulators of immunity. Their inhibitory function has been associated primarily with interleukin 10 (IL-10) because B-cell-derived IL-10 can protect against autoimmune disease and increase susceptibility to pathogens. Here we identify IL-35-producing B cells as key players in the negative regulation of immunity.

A novel C5a-neutralizing mirror-image (l-)aptamer prevents organ failure and improves survival in experimental sepsis.

Complement factor C5a is a potent proinflammatory mediator that contributes to the pathogenesis of numerous inflammatory diseases. Here, we describe the discovery of NOX-D20, a PEGylated biostable mirror-image mixed (l-)RNA/DNA aptamer (Spiegelmer) that binds to mouse and human C5a with picomolar affinity. In vitro, NOX-D20 inhibited C5a-induced chemotaxis of a CD88-expressing cell line and efficiently antagonized the activation of primary human polymorphonuclear leukocytes (PMN) by C5a.

Activation of CD4⁺ Foxp3⁺ regulatory T cells proceeds normally in the absence of B cells during EAE.

B cells and regulatory T (Treg) cells can both facilitate remission from experimental auto immune encephalomyelitis (EAE), a disease of the central nervous system (CNS) used as a model for multiple sclerosis (MS). Considering that B-cell-depletion therapy (BCDT) is used to treat MS patients, we asked whether Treg-cell activation depended on B cells during EAE. Treg-cell proliferation, accumulation in CNS, and augmentation of suppressive activity in the CNS were normal in B-cell-deficient mice, indicating that B cells are not essential for activation of the protective Treg-cell response and thus provide an independent layer of regulation.

Immune regulation by B cells and antibodies a view towards the clinic.

B lymphocytes contribute to immunity in multiple ways, including production of antibodies, presentation of antigen to T cells, organogenesis of secondary lymphoid organs, and secretion of cytokines. Recent clinical trials have shown that depleting B cells can be highly beneficial for patients with autoimmune diseases, implicating B cells and antibodies as key drivers of pathology. However, it should be kept in mind that B cell responses and antibodies also have important regulatory roles in limiting autoimmune pathology.

TLR-activated B cells suppress T cell-mediated autoimmunity.

TLR sense microbial infections, and control activation of immune responses. Dendritic cells, macrophages, and B lymphocytes express TLR and the TLR-signaling adaptor protein MyD88. The impact of TLR-activated B cells on T cell-mediated inflammation is unknown.

CD83 is a regulator of murine B cell function in vivo.

The transmembrane glycoprotein CD83 has been described as a specific maturation marker for dendritic cells and several lines of evidence suggest that CD83 regulates thymic T cell maturation as well as peripheral T cell activation. Here we show for the first time that CD83 is involved also in the regulation of B cell function. CD83 is up-regulated on activated B cells in vivo, specifically in the draining lymph nodes of Leishmania major-infected mice.