Biology subjects

Hirzel, C.

Publications and source records attributed to Hirzel, C..

2 recordsLinked to original sources

bioRxiv2026

Developmental and molecular features shaping broad and synergistic actions of human autoantibodies targeting interferon-α

Neutralizing autoantibodies against interferon- (IFN) are associated with severe viral infections but may improve outcomes in IFN-driven autoimmunity. How these antibodies emerge, mature, and function at the molecular level remains unclear. Here, we tracked development of plasma neutralizing activity against all 12 IFNs in multiple human donors over years. Plasma neutralization frequently initiates with narrow IFN specificity, often IFN8, but increases in breadth and potency with individual kinetics. Monoclonal antibody analyses reveal that affinity maturation generates epitope-specific antibody classes, highlighting parallel emergence of subtype-restricted and broadly-reactive antibodies. Biophysical and structural characterization of human antibody-IFN complexes uncovers determinants of initial specificity and breadth development. Strikingly, antibodies engaging non-competing, neutralizing epitopes can act co-operatively to block IFN signaling, and some combinations trigger Fc-effector functions via cell surface IFN:IFNAR2 interactions that may eliminate IFN-responsive cells. Our findings reveal features shaping anti-IFN autoantibody repertoires and unappreciated synergistic mechanisms that amplify their potency and pathogenic potential.

immunology↗

bioRxiv2021

LRR protein RNH1 inhibits inflammasome activation through proteasome-mediated degradation of Caspase-1 and is associated with adverse clinical outcomes in COVID-19 patients.

Inflammasomes are cytosolic innate immune sensors of pathogen infection and cellular damage that induce caspase-1 mediated inflammation upon activation. Although inflammation is protective, uncontrolled excessive inflammation can cause inflammatory diseases and can be detrimental, such as in COVID-19. However, the underlying mechanisms that control inflammasome activation are incompletely understood. Here we report that the leucine rich repeat (LRR) protein Ribonuclease inhibitor (RNH1), which shares homology with LRRs of NLRP proteins, attenuates inflammasome activation. Deletion of RNH1 in macrophages increases IL-1{beta} production and caspase-1 activation for inflammasome stimuli. Mechanistically, RNH1 decreases pro-IL-1{beta} expression and induces proteasome-mediated caspase-1 degradation. Corroborating this, mouse models of monosodium urate (MSU)-induced peritonitis and LPS-induced endotoxemia, which are dependent on caspase-1, respectively show increased neutrophil infiltration and lethality in Rnh1-/- mice compared to WT mice. Furthermore, RNH1 protein levels are negatively correlated with inflammation and disease severity in hospitalized COVID-19 patients. We propose that RNH1 is a new inflammasome regulator with relevance to COVID-19 severity.

immunology↗