Leptin receptor (LepR) signaling plays an essential role in balancing food intake and energy expenditure. The architecture of LepR signaling assembly is critical for its function. In this study, we determined the structures of three distinct conformations of human leptin–LepR using cryo-electron microscopy at resolutions of 3.88, 3.77, and 3.58 Å. Both 2:2 and 3:3 stoichiometric assemblies were observed, and the complexes exhibited asymmetric open conformations. Leptin undergoes substantial rearrangement of its flexible regions to accommodate binding to LepR. The assembled leptin–LepR complexes connect through a “hand-in-hand” geometry. The open, interlocked 3:3 trimeric assembly results from the engagement of a third leptin–LepR heterodimer with a 2:2 dimer. The asymmetric geometry of LepR is substantially distinct from that of other gp130 cytokine homologs, and that may be due to the twisted and rigid interface between the D3 and D4 domains. These results highlight the distinct engagement of leptin with LepR and provide important insights into the structural plasticity of LepR-signaling assemblies.

Respiratory syncytial virus (RSV) is one of the leading pathogens that cause lower respiratory tract infections in infants and the elderly. Passive immunoprophylaxis with monoclonal antibody (mAb) has been approved to prevent morbidity and mortality from RSV infection in infants. Here we report the isolation of two neutralizing mAbs against RSV from convalescent children by prefusion form of fusion (F) glycoprotein as bait. One mAb RV11 exhibited good potency in neutralization of RSV strains from both A and B subtypes in cell-based assay, and protected mice from RSV infection in vivo. An RV11 escape mutant was identified, which contains an S443P mutation in F protein. Crystal structure showed the RV11 bound to a conserved prefusion epitope across the antigenic sites Ⅳ and Ⅴ of the F glycoprotein. RV11 showed a strong synergistic effect when combined with two RSV antivirals, an F-targeting small molecular inhibitor ziresovir and a site Ø neutralizing mAb D25 (the parental mAb for nirsevimab). The study extended our knowledge to the neutralizing and protective epitopes of RSV, and the mAb RV11 deserves further development for clinical translation.

Many severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)–related coronaviruses have been discovered, constituting potential threats to human health. However, it remains unclear whether the currently available vaccines are effective against these coronaviruses. Here, we constructed a wild-type mouse model to evaluate pathogenicity of the SARS-CoV-2-related pangolin coronavirus GX/P2V/2017 and neutralization efficacy of the approved tandem-repeat SARS-CoV-2 spike receptor-binding domain (RBD) vaccine ZF2001. We found that ZF2001-induced cross-reactive and cross-neutralizing antibodies against GX/P2V/2017, and the vaccination alleviated the pathological lung damage caused by GX/P2V/2017 in mice. These results indicate that RBD may work as a promising candidate for pan-coronavirus vaccine development.