Fortuitous Somatic Mutations during Antibody Evolution Endow Broad Neutralization against SARS-CoV-2 Omicron Variants

Striking antibody evasion by emerging circulating SARS-CoV-2 variants drives the identification of broadly neutralizing antibodies (bNAbs). However, how a bNAb acquires increased neutralization breadth during antibody evolution is still elusive. Here, we identified a clonally-related antibody family from a convalescent individual. One of the members, XG005, exhibited potent and broad neutralizing activities against SARS-CoV-2 variants, while the other members showed significant reductions in neutralization breadth and potency, especially against the Omicron sublineages. Structural analysis visualizing the XG005-Omicron spike binding interface revealed how crucial somatic mutations endowed XG005 with greater neutralization potency and breadth. A single administration of XG005 with extended half-life, reduced antibody-dependent enhancement (ADE) effect, and increased antibody product quality, exhibited a high therapeutic efficacy in BA.2- and BA.5-challenged mice. Our results provided a natural example to show the importance of somatic hypermutation during antibody evolution for SARS-CoV-2 neutralization breadth and potency.

A potent SARS-CoV-2 antibody neutralizes Omicron variant by disassembling the spike trimer

The continuous emergence of novel SARS-CoV-2 variants poses new challenges to the fight against the COVID-19 pandemic. The newly emerging Omicron strain caused serious immune escape and raised unprecedented concern all over the world. The development of antibody targeting conserved and universal epitope is urgently needed. A subset neutralizing antibody(nAbs) against COVID-19 from convalescent patients were isolated in our previous study. Here in this study, we investigated the accommodation of these nAbs to SARS-CoV-2 variants of concerns (VOCs), revealing that IgG 553-49 neutralizes pseudovirus of SARS-CoV-2 Omicron variant. In addition, we determined the cryo-EM structure of SARS-CoV-2 spike complexed with three antibodies targeting different epitopes, including 553-49, 553-15 and 553-60. Notably, 553-49 targets a novel conserved epitope and neutralizes virus by disassembling spike trimers. 553-15, an antibody that neutralizes all the other VOCs except omicron, cross-links two spike trimers to form trimer dimer, demonstrating that 553-15 neutralizes virus by steric hindrance and virion aggregation. These findings suggest the potential to develop 49 and other antibody targeting this highly conserved epitope as promising cocktail therapeutics reagent for COVID-19. ImportanceThe newly emergence of Omicron strain caused higher immune escape, raising unprecedented concerns about the effectiveness of antibody therapies and vaccines. In this study, we identified a SARS-CoV-2 Omicron neutralizing antibody 553-49, which neutralizes Omicron variant by targeting a completely conserved novel epitope. Besides, we revealed that IgG 553-15 neutralizes SARS-CoV-2 by crosslinking virions and 553-60 functions by blocking receptor binding. Comparison of different RBD epitopes revealed that the epitope of 553-49 is hidden in the S trimer and keeps high conservation during SARS-CoV-2 evolution, making 553-49 a promising therapeutics reagent to fight against the emerging Omicron and future variant of SARS-CoV-2.

Combating the SARS-CoV-2 Omicron variant with non-Omicron neutralizing antibodies

The highly mutated and transmissible Omicron variant has provoked serious concerns over its decreased sensitivity to the current coronavirus disease 2019 (COVID-19) vaccines and evasion from most anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) neutralizing antibodies (NAbs). In this study, we explored the possibility of combatting the Omicron variant by constructing bispecific antibodies based on non-Omicron NAbs. We engineered ten IgG-like bispecific antibodies with non-Omicron NAbs named GW01, 16L9, 4L12, and REGN10987 by fusing the single-chain variable fragments (scFvs) of two antibodies through a linker and then connecting them to the Fc region of IgG1. Surprisingly, eight out of ten bispecific antibodies showed high binding affinity to the Omicron receptor-binding domain (RBD) and exhibited extreme breadth and potency against pseudotyped SARS-CoV-2 variants of concern (VOCs) including Omicron, as well as authentic Omicron(+R346K) variants. Six bispecific antibodies containing the cross-NAb GW01 neutralized Omicron variant and retained their abilities to neutralize other sarbecoviruses. Bispecific antibodies inhibited Omicron infection by binding to the ACE2 binding site. A cryo-electron microscopy (cryo-EM) structure study of the representative bispecific antibody FD01 in complex with the Omicron spike (S) revealed 5 distinct trimers and one unique bi-trimer conformation. The structure and mapping analyses of 34 Omicron S variant single mutants elucidated that two scFvs of the bispecific antibody synergistically induced the RBD-down conformation into 3-RBD-up conformation, enlarged the interface area, accommodated the S371L mutation, improved the affinity between a single IgG and the Omicron RBD, and hindered ACE2 binding by forming bi-trimer conformation. Our study offers an important foundation for anti-Omicron NAb design. Engineering bispecific antibodies based on non-Omicron NAbs may provide an efficient solution to combat the Omicron variant.

Broad neutralization of SARS-CoV-2 variants by an inhalable bispecific single-domain antibody

The effectiveness of SARS-CoV-2 vaccines and therapeutic antibodies has been limited by the continuous emergence of viral variants, and by the restricted diffusion of antibodies from circulation into the sites of respiratory virus infection. Here, we report the identification of two highly conserved regions on Omicron variant RBD recognized by broadly neutralizing antibodies. Based on this finding, we generated a bispecific single-domain antibody that was able to simultaneously and synergistically bind these two regions on a single Omicron variant RBD as revealed by Cryo-EM structures. This inhalable antibody exhibited exquisite neutralization breadth and therapeutic efficacy in mouse models of SARS-CoV-2 infections. The structures also deciphered an uncommon cryptic epitope within the spike trimeric interface that may have implications for the design of broadly protective SARS-CoV-2 vaccines and therapeutics.

Characteristics of the sleep structures of patients with both chronic insomnia and obstructive sleep apnea in plateau area / 中华健康管理学杂志

Objective:To explore the characteristics of the sleep structures of patients with both chronic insomnia and obstructive sleep apnea (OSA) in plateau area.Methods:Polysomography Alice 5 was applied to 23 patients with primary chronic insomnia [insomnia group, age (48.2±9.9) years], 22 patients with both chronic insomnia and OSA [comorbidity group, age (46.8±8.9) years], who both came from Qinghai Red Cross Hospital between January, 2014 to June, 2015 and 20 subjects with normal sleep [healthy group, age (46.2±7.1) years] in plateau area (mainly in Xining, altitude 2 250 meters or above) to compare and explore their sleep structures by the whole night sleep monitoring in the sleep monitoring room. The sleep structures were compared according to the American Academy of Sleep Medicine (AASM) Manual for the Scoring of Sleep and Associated Events.Results:Compared to healthy group, insomnia group and comorbidity group both had significantly lower sleep efficiency [(62.4%±16.7%), (59.8%±16.0%) vs (80.9%±8.8%)], non-rapid eye movement (NREM) phase 2 sleep ratio [(37.9%±12.2%), (36.2%±12.5%) vs (49.7%±6.2%)] and rapid eye movement (REM) sleep ratio [(7.7%±4.0%), (6.5%±4.0%) vs (12.5%±4.6%)] (all P<0.05); comorbidity group had a significantly higher oxygen desaturation index than insomnia group and healthy group [(30.8±29.2) vs (7.9±7.5), (5.9±2.7) times/h] ( P<0.05); insomnia group′s sleep latency of NREM3 stage was significantly longer than comorbidity group and healthy group [(148.9±113.6) vs (89.3±51.8), (59.1±40.3) min] (both P<0.05). Conclusion:Patients with both chronic insomnia and OSA and patients with chronic insomnia only in plateau area have different sleep structures, and both of their sleep quality are lower than the people with normal sleep; patients with both chronic insomnia and OSA could enter deep sleep more quickly after sleep onset.

Enteric dysbiosis-linked gut barrier disruption triggers early renal injury induced by chronic high salt feeding in mice

Chronic high-salt diet-associated renal injury is a key risk factor for the development of hypertension. However, the mechanism by which salt triggers kidney damage is poorly understood. Our study investigated how high salt (HS) intake triggers early renal injury by considering the ‘gut-kidney axis’. We fed mice 2% NaCl in drinking water continuously for 8 weeks to induce early renal injury. We found that the ‘quantitative’ and ‘qualitative’ levels of the intestinal microflora were significantly altered after chronic HS feeding, which indicated the occurrence of enteric dysbiosis. In addition, intestinal immunological gene expression was impaired in mice with HS intake. Gut permeability elevation and enteric bacterial translocation into the kidney were detected after chronic HS feeding. Gut bacteria depletion by non-absorbable antibiotic administration restored HS loading-induced gut leakiness, renal injury and systolic blood pressure elevation. The fecal microbiota from mice fed chronic HS could independently cause gut leakiness and renal injury. Our current work provides a novel insight into the mechanism of HS-induced renal injury by investigating the role of the intestine with enteric bacteria and gut permeability and clearly illustrates that chronic HS loading elicited renal injury and dysfunction that was dependent on the intestine.

Visual function and morphological changes in the macular area of patients with type 2 diabetes mellitus after intensive insulin therapy / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Intensive insulin therapy has been found to lessen the progress of diabetic retinopathy (DR) to some extent, while it has also been implicated to be responsible for decrease of DR. We investigated visual function and morphological changes in the macular area in short-term follow-up of patients with type 2 diabetes mellitus after intensive insulin therapy.</p><p><b>METHODS</b>This was a prospective clinical study of nonproliferative DR patients (102 eyes, 120 patients) undergoing intensive insulin therapy. The Contrast Glare Tester (Takagi CGT-1000) was used to examine contrast sensitivity (CS) and Heidelberg Retina Tomograph (HRT) II and Stratus Model 3000 OCT were used to observe the changes of morphology in the macular area. Follow-up times were pre-intensive therapy, 3 and 6 months post-intensive therapy.</p><p><b>RESULTS</b>CS at low and middle frequencies was higher at 3 and 6 months post-therapy compared with pre-therapy (P < 0.05). Significant differences in CS at low frequency were found between 6 and 3 months post-therapy (P < 0.05). Macular edema index was lower in the first, second, and third rings of the macular area after intensive therapy compared with pre-therapy (P < 0.05). Compared with 3 months post-therapy, the macular edema index was lower in the first, second, and third rings of the macular area at 6 months post-therapy (P > 0.05). No significant differences in the thickness of the first, second, and third rings of the macular area were detected between 3 and 6 months post-therapy and pre-therapy (P > 0.05).</p><p><b>CONCLUSION</b>CS and macular edema indexes were significantly improved in nonproliferative diabetic retinopathy patients after intensive insulin therapy, but thickness of the macular area was unchanged.</p>

The influence of labor analgesia on maternal T-lymphocyte subsets / 中国基层医药

Objective To observe the subarachnoid space the epidural space joint block labor analgesia (CSEA) changes of T lymphocyte subsets.Methods 100 cases of full-term mothers were randomly divided into two groups,analgesia group and the control group.The analgesic group row CSEA childbirth analgesia.Two groups of maternal cervix large 2 to 3cm (T1),when the baby was delivered (T2),24h (T3),blood was colleoted after childbirth,detected by radioimmunoassay of cortisol.Flow cytometry assay was wsed to test T lymphocyte subsets CD3+,CD4+,CD8+,CD4+/CD8+,And the birth process,Apgar score,Labor pain visual analogue score (VAS) were recoroded.Results (1) Active phase of the first stage of childbirth analgesia group was significantly shorter than the control group (t =2.182,P ＜ 0.05).The second and third stage of Childbirth and neonatal Apgar score difference between the two groups was not statistically significant.(2)Serum cortisol concentration at T2 analgesia group was significantly lower that of than the control group (P ＜ 0.05).(3) The two groups in maternal blood of CD3+,CD4+,CD4+ / CD8+ were reduced to varying degrees,T3 was reduced significantly (P ＜ 0.05),Analgesia group was significantly lower than that of the control group (all P ＜ 0.05).Conclusion CSEA analgesia in Childbirth can shorten the first stage of Childbirth active period,has no significant effect on the Apgar score,can alleviate the pain and stress reactions such as the suppression of the maternal immune function.