Sepsis is a life-threatening condition driven by dysregulated immune responses to infection, characterized by excessive inflammatory cytokine release that frequently culminates in cytokine storm and multi-organ failure, yet the molecular mechanisms governing cytokine regulation of monocytes in sepsis remain poorly understood. In this study, we retrieved RNA-sequencing (RNA-seq) datasets regarding cytokine storm-related diseases from the Gene Expression Omnibus (GEO) and performed comparative analysis of gene expression profiles among patients with sepsis, severe COVID-19, macrophage activation syndrome, and healthy controls to identify critical cytokine regulatory genes. We identified 109 shared differentially expressed genes across these cytokine storm-related diseases and pinpointed Formyl peptide receptor 1 (FPR-1) as a key gene significantly upregulated in sepsis monocytes via LPS/TLR4 pathway. Furthermore, we found that FPR-1 activation enhances LPS-induced IL-6 and TNF-α production through AKT and p38-MAPK signaling. Furthermore, FPR-1 modulates mitochondrial ROS levels, thereby amplifying pro-inflammatory cytokine expression in a mitochondrial ROS-dependent manner. These findings demonstrate that FPR-1 is a crucial modulator of monocyte-driven cytokine dysregulation in sepsis via key inflammatory signaling pathways and mtROS homeostasis, providing novel mechanistic insights and potential therapeutic targets for sepsis management.

The COVID-19 pandemic, caused by the SARS-CoV-2 virus, has had and continues to have a significant impact on global public health. One of the characteristics of SARS-CoV-2 is a surface homotrimeric spike protein, which is primarily responsible for the host immune response upon infection. Here we present the preclinical studies of a broadly protective SARS-CoV-2 subunit vaccine developed from our trimer domain platform using the Delta spike protein, from antigen design through purification, vaccine evaluation and manufacturability. The pre-fusion trimerized Delta spike protein, PF-D-Trimer, was highly expressed in Chinese hamster ovary (CHO) cells, purified by a rapid one-step anti-Trimer Domain monoclonal antibody immunoaffinity process and prepared as a vaccine formulation with an adjuvant. Immunogenicity studies have shown that this vaccine candidate induces robust immune responses in mouse, rat and Syrian hamster models. It also protects K18-hACE2 transgenic mice in a homologous viral challenge. Neutralizing antibodies induced by this vaccine show cross-reactivity against the ancestral WA1, Delta and several Omicrons, including BA.5.2. The formulated PF-D Trimer is stable for up to six months without refrigeration. The Trimer Domain platform was proven to be a key technology in the rapid production of PF-D-Trimer vaccine and may be crucial to accelerate the development and accessibility of updated versions of SARS-CoV-2 vaccines.

Severe acute respiratory syndrome coronavirus 2（SARSCo V-2） infection can result in more severe syndromes and poorer outcomes in patients with diabetes and obesity.However, the precise mechanisms responsible for the combined impact of coronavirus disease 2019（COVID-19） and diabetes have not yet been elucidated,and effective treatment options for SARS-Co V-2-infected diabetic patients remain limited. To investigate the disease pathogenesis, K18-h ACE2 transgenic(h ACE2 Tg ) mice with a leptin receptor deficiency(h ACE2-Lepr -/- ) and high-fat diet（h ACE2-HFD） background were generated. The two mouse models were intranasally infected with a 5×10~5 median tissue culture infectious dose(TCID 50 ) of SARSCo V-2, with serum and lung tissue samples collected at 3days post-infection. The h ACE2-Lepr -/- mice were then administered a combination of low-molecular-weight heparin（LMWH）（1 mg/kg or 5 mg/kg） and insulin via subcutaneous injection prior to intranasal infection with1×10~4 TCID 50 of SARS-Co V-2. Daily drug administration continued until the euthanasia of the mice. Analyses of viral RNA loads, histopathological changes in lung tissue,and inflammation factors were conducted. Results demonstrated similar SARS-Co V-2 susceptibility in h ACE2 Tg mice under both lean（chow diet） and obese（HFD） conditions. However, compared to the h ACE2-Lepr +/+ mice, h ACE2-Lepr -/- mice exhibited more severe lung injury, enhanced expression of inflammatory cytokines and hypoxia-inducible factor-1α（HIF-1α）, and increased apoptosis. Moreover, combined LMWH and insulin treatment effectively reduced disease progression and severity, attenuated lung pathological changes, and mitigated inflammatory responses. In conclusion, preexisting diabetes can lead to more severe lung damage upon SARS-Co V-2 infection, and LMWH may be a valuable therapeutic approach for managing COVID-19patients with diabetes.

BACKGROUND: Wasp stings are a serious problem worldwide, and patients in severe cases may experience multi-organ failure. However, the mechanism of hypolipidemia in patients with wasp stings is unknown. OBJECTIVE: To investigate the relationship between early changes in lipid levels and clinical severity and the possible underlying mechanisms. METHODS: A retrospective analysis of 212 patients (mild: 77; moderate: 50; severe: 85) with wasp stings was conducted. Clinical data, including lipid test results within 24 h of admission, were analysed. A total of 1060 healthy age- and gender-matched controls were used. RESULTS: Patients with wasp stings had lower lipid levels than healthy controls ( P < 0.01). Lipid levels decreased with disease severity, except for triglycerides ( P < 0.05). The number of stings, degree of organ failure, need for mechanical ventilation and extracorporeal blood purification, and mortality were higher in the severe group than in the mild and moderate groups ( P < 0.01). A decrease in lipid levels was accompanied by an increase in inflammatory indicators. In the severe group, a reduction in lipid levels was associated with ventilator application and blood purification, independent of survival status. CONCLUSIONS: Patients with wasp stings experience a reduction in lipid levels, which is related to the severity of clinical manifestations. Early lipid levels may serve as a simple indicator for the severity of wasp stings, and targeting lipid metabolism may be a novel treatment. (c) 2022 National Lipid Association. Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )

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.

The highly mutated and transmissible Omicron (BA.1) and its more contagious lineage BA.2 have provoked serious concerns over their decreased sensitivity to the current COVID-19 vaccines and evasion from most anti-SARS-CoV-2 neutralizing antibodies (NAbs). In this study, we explored the possibility of combating the Omicron and BA.2 by constructing bispecific antibodies based on non-Omicron NAbs. We engineered 10 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, 8 out of 10 bispecific antibodies showed high binding affinities to the Omicron receptor-binding domain (RBD) and exhibited extreme breadth and potency against pseudotyped SARS-CoV-2 variants of concern (VOCs) including Omicron and BA.2, with geometric mean of 50% inhibitory concentration (GM IC 50 ) values ranging from 4.5 ng/mL to 103.94 ng/mL, as well as the authentic BA.1.1. Six bispecific antibodies containing the cross-NAb GW01 not only neutralized Omicron and BA.2, but also neutralized the sarbecoviruses including SARS-CoV and SARS-related coronaviruses (SARSr-CoVs) RS3367 and WIV1, with GM IC 50 ranging from 11.6 ng/mL to 103.9 ng/mL. Mapping analyses of 42 spike (S) variant single mutants of Omicron and BA.2 elucidated that these bispecific antibodies accommodated the S371L/F mutations, which were resistant to most of the non-Omicron NAbs. A cryo-electron microscopy (cryo-EM) structure study of the representative bispecific antibody GW01-16L9 (FD01) in its native full-length IgG form in complex with the Omicron S trimer revealed 5 distinct trimers and one novel trimer dimer conformation. 16L9 scFv binds the receptor-binding motif (RBM), while GW01 scFv binds a epitope outside the RBM. Two scFvs of the bispecific antibody synergistically induced the RBD-down conformation into 3 RBD-up conformation, improved the affinity between IgG and the Omicron RBD, induced the formation of trimer dimer, and inhibited RBD binding to ACE2. The trimer dimer conformation might induce the aggregation of virions and contribute to the neutralization ability of FD01. These novel bispecific antibodies are strong candidates for the treatment and prevention of infection with the Omicron, BA.2, VOCs, and other sarbecoviruses. Engineering bispecific antibodies based on non-Omicron NAbs could turn the majority of NAbs into a powerful arsenal to aid the battle against the pandemic.

A safe, efficacious and deployable vaccine is urgently needed to control COVID-19 pandemic. We report here the preclinical development of a COVID-19 vaccine candidate, ZF2001, which contains tandem-repeat dimeric receptor-binding domain (RBD) protein with alum-based adjuvant. We assessed vaccine immunogenicity and efficacy in both mice and non-human primates (NHPs). ZF2001 induced high levels of RBD-binding and SARS-CoV-2 neutralizing antibody in both mice and NHPs, and also elicited balanced TH1/TH2 cellular responses in NHPs. Two doses of ZF2001 protected Ad-hACE2-transduced mice against SARS-CoV-2 infection, as detected by reduced viral RNA and relieved lung injuries. In NHPs, vaccination of either 25 μg or 50 μg ZF2001 prevented infection with SARS-CoV-2 in lung, trachea and bronchi, with milder lung lesions. No evidence of disease enhancement is observed in both models. ZF2001 is being evaluated in the ongoing international multi-center Phase 3 trials (NCT04646590) and has been approved for emergency use in Uzbekistan.

The emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) variants of concern, including Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Delta (B.1.617.2), and Omicron (B.1.1.529) has aroused concerns over their increased infectivity and transmissibility, as well as decreased sensitivity to SARS-CoV-2-neutralizing antibodies (NAbs) and the current coronavirus disease 2019 (COVID-19) vaccines. Such exigencies call for the development of pan-sarbecovirus vaccines or inhibitors to combat the circulating SARS-CoV-2 NAb-escape variants and other sarbecoviruses. In this study, we isolated a broadly NAb against sarbecoviruses named GW01 from a donor who recovered from COVID-19. Cryo-EM structure and competition assay revealed that GW01 targets a highly conserved epitope in a wide spectrum of different sarbecoviruses. However, we found that GW01, the well-known sarbecovirus NAb S309, and the potent SARS-CoV-2 NAbs CC12.1 and REGN10989 only neutralize about 90% of the 56 tested currently circulating variants of SARS-CoV-2 including Omicron. Therefore, to improve efficacy, we engineered an IgG-like bispecific antibody GW01-REGN10989 (G9) consisting of single-chain antibody fragments (scFv) of GW01 and REGN10989. We found that G9 could neutralize 100% of NAb-escape mutants (23 out of 23), including Omicron variant, with a geometric mean (GM) 50% inhibitory concentration of 8.8 ng/mL. G9 showed prophylactic and therapeutic effects against SARS-CoV-2 infection of both the lung and brain in hACE2-transgenic mice. Site-directed mutagenesis analyses revealed that GW01 and REGN10989 bind to the receptor-binding domain in different epitopes and from different directions. Since G9 targets the epitopes for both GW01 and REGN10989, it was effective against variants with resistance to GW01 or REGN10989 alone and other NAb-escape variants. Therefore, this novel bispecific antibody, G9, is a strong candidate for the treatment and prevention of infection by SARS-CoV-2, NAb-escape variants, and other sarbecoviruses that may cause future emerging or re-emerging coronavirus diseases.

Abstract Background The outbreak of COVID-19 has resulted in serious concerns in China and abroad. To investigate clinical features of confirmed and suspected patients with COVID-19 in west China, and to examine differences between severe versus non-severe patients. Methods Patients admitted for COVID-19 between January 21 and February 11 from fifteen hospitals in Sichuan Province, China were included. Experienced clinicians trained with methods abstracted data from medical records using pre-defined, pilot-tested forms. Clinical characteristics between severe and non-severe patients were compared. Results Of the 169 patients included, 147 were laboratory-confirmed, 22 were suspected. For confirmed cases, the most common symptoms from onset to admission were cough (70·7%), fever (70·5%) and sputum (33·3%), and the most common chest CT patterns were patchy or stripes shadowing (78·0%); throughout the course of disease, 19·0% had no fever, and 12·4% had no radiologic abnormality; twelve (8·2%) received mechanical ventilation, four (2·7%) were transferred to ICU, and no death occurred. Compared to non-severe cases, severe ones were more likely to have underlying comorbidities (62·5% vs 26·2%, P = 0·001), to present with cough (92·0% vs 66·4%, P = 0·02), sputum (60·0% vs 27·9%, P = 0·004) and shortness of breath (40·0% vs 8·2%, P < 0·0001), and to have more frequent lymphopenia (79·2% vs 43·7%, P = 0·003) and eosinopenia (84·2% vs 57·0%, P = 0·046). Conclusions The symptoms of patients in west China were relatively mild, and an appreciable proportion of infected cases had no fever, warranting special attention.

Influenza neuraminidase (NA) is able to induce cross-subtype immunity and is considered as a promising target for the development of universal influenza vaccines. However, commercial influenza vaccines only induced low NA-specific immune responses due to the low amounts and the denatured conformation of NA proteins in current inactivated or split influenza vaccines. Here we investigated the protective efficacy of recombinant tetrameric and monomeric NA proteins to determine whether the conformation contributed to induce protective immunity. We found that H1N1(P)(R)(8)NA tetramer (NA(tet)) could provide complete homologous protection against A/PR8 (H1N1) virus infection in mice, while the protection of H1N1(P)(R)(8)NA monomer (NA(mono)) was moderate. Higher levels of NA-reactive binding and inhibition antibodies and less weight loss were observed in the H1N1(P)(R)(8)NA(tet)-vaccinated group. Similarly, H5N1(V)(N)NA(tet) immunization exhibited a preferable heterologous protection than H5N1(V)(N)NA(mono), but neither H7N9(S)(H)NA(tet) nor H7N9(S)(H)NA(mono) vaccination showed heterosubtypic protection. We also compared the effect of three adjuvants, aluminum, 3 ' 3 '-cGAMP (cGAMP), and Poly(I:C), on the humoral response and protective efficacy induced by H1N1(P)(R)(8)NA(tet). H1N1(P)(R)(8)NA(tet) protein adjuvanted with aluminum was observed to exhibited better capacity in inducing NA-specific humoral immunity and preventing weight loss than with cGAMP or Poly(I:C). In conclusion, our data demonstrate that tetrameric NA with natural conformation is required to induce protective anti-NA immunity. The NA tetramer could provide homologous protection and subtype-specific cross-protection. In addition, the aluminum adjuvant is preferable in recombinant NA protein vaccination.

IMPORTANCE The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) threatens global public health. The association between clinical characteristics of the virus and neutralizing antibodies (NAbs) against this virus have not been well studied. OBJECTIVE To examine the association between clinical characteristics and levels of NAbs in patients who recovered from COVID-19. DESIGN, SETTING, AND PARTICIPANTS In this cohort study, a total of 175 patients with mild symptoms of COVID-19 who were hospitalized from January 24 to February 26, 2020, were followed up until March 16, 2020, at Shanghai Public Health Clinical Center, Shanghai, China. EXPOSURES SARS-CoV-2 infections were diagnosed and confirmed by reverse transcriptase-polymerase chain reaction testing of nasopharyngeal samples. MAIN OUTCOMES AND MEASURES The primary outcome was SARS-CoV-2-specific NAb titers. Secondary outcomes included spike-binding antibodies, cross-reactivity against SARS-associated CoV, kinetics of NAb development, and clinical information, including age, sex, disease duration, length of stay, lymphocyte counts, and blood C-reactive protein level. RESULTS Of the 175 patients with COVID-19, 93 were female (53%); the median age was 50 (interquartile range [IQR], 37-63) years. The median length of hospital stay was 16 (IQR, 13-21) days, and the median disease duration was 22 (IQR, 18-26) days. Variable levels of SARS-CoV-2-specific NAbs were observed at the time of discharge (50% inhibitory dose [ID50], 1076 [IQR, 448-2048]). There were 10 patients whose NAb titers were less than the detectable level of the assay (ID50, <40), and 2 patients who showed very high titers of NAbs, with ID50 levels of 15 989 and 21 567. NAbs were detected in patients from day 4 to 6 and reached peak levels from day 10 to 15 after disease onset. NAbs were unable to cross-react with SARS-associated CoV and NAb titers correlated with the spike-binding antibodies targeting S1 (r = 0.451; 95% CI, 0.320-0.564; P<.001), receptor binding domain (r = 0.484; 95% CI, 0.358-0.592; P<.001), and S2 regions (r = 0.346; 95% CI, 0.204-0.473; P<.001). NAb titers at the time of discharge were significantly higher in the 82 men (1417 [IQR, 541-2253]) than those in the 93 women (905 [IQR, 371-1687]) (median difference, 512; 95% CI, 82-688; P=.01) and at the time of follow-up in 56 male patients (1049 [IQR, 552-2454]) vs 61 female patients (751 [IQR, 216-1301]) (median difference, 298; 95% CI, 86-732; P=.009). Plasma NAb titers were significantly higher in 56 older (1537 [IQR, 877-2427) and 63 middle-aged (1291 [IQR, 504-2126]) patients than in 56 younger patients (459 [IQR, 225-998]) (older vs younger: median difference, 1078; 95% CI, 548-1287; P<.001; middle-aged vs younger: median difference, 832; 95% CI, 284-1013; P<.001). The NAb titers were correlated with plasma C-reactive protein levels (r=0.508; 95% CI, 0.386-0.614; P<.001) and negatively correlated with lymphocyte counts (r=-0.427; 95% CI, -0.544 to -0.293; P<.001) at the time of admission. CONCLUSIONS AND RELEVANCE In this cohort study, among 175 patients who recovered from mild COVID-19 in Shanghai, China, NAb titers to SARS-CoV-2 appeared to vary substantially. Further research is needed to understand the clinical implications of differing NAb titers for protection against future infection.

In this study, we intended to determine the detailed function and mechanism of long noncoding RNA (lncRNA) colorectal neoplasia differentially expressed (CRNDE) in liver injury induced by sepsis. Cecal ligation and perforation (CLP) models were adopted to induce sepsis in vivo with rats, and hepatic epithelial cells L02 were treated with lipopolysaccharide (LPS) to mimic sepsis in vitro. Enzyme‐linked immunosorbent assay was conducted to detect the levels of tumor necrosis factor (TNF‐α), interleukin‐6 (IL‐6), interleukin‐10 (IL‐10), and interferon‐γ (IFN‐γ) in the serum of rats. Quantitative real‐time polymerase chain reaction (qRT‐PCR) was performed to measure the expressions of CRNDE and microRNA‐126‐5p (miR‐126‐5p). Flow cytometry analysis and Cell Counting Kit‐8 (CCK‐8) method were carried out followed by the up‐ or downregulation of CRNDE and miR‐126‐5p to monitor the proliferation and apoptosis of L02 cells, respectively. Western blot was then applied to determine the expressions of cysteinyl aspartate specific proteinase 3 (caspase 3), poly(ADP‐ribose)polymerase (PARP), cytochrome c, and BCL2‐like 2 (BCL2L2). The interactions between CRNDE with miR‐126‐5p and miR‐126‐5p with BCL2L2 were determined through bioinformatics, qRT‐PCR, dual luciferase reporter assay, and RNA immunoprecipitation assay. CRNDE was significantly decreased in liver tissues and hepatic cells in sepsis models. Upregulation of CRNDE promoted the viability of L02 cells and inhibited their apoptosis, while downregulation of CRNDE had opposite effects. The expression of CRNDE in liver tissues of septic rats was correlated with the expression miR‐126‐5p. It was also demonstrated that the transfection of miR‐126‐5p mimics reversed the inhibitory effect induced by CRNDE on apoptosis of L02 cells. CRNDE could specifically bind to miR‐126‐5p and reduce its expression, in turn promote the expression of BCL2L2. Additionally, CRNDE overexpression in rats ameliorated liver injury induced by sepsis. Downregulated CRNDE aggravates hepatic injury via regulating miR‐126‐5p and BCL2L2 during sepsis.

AbstractAntibody-dependent enhancement (ADE) has been reported in several virus infections including dengue fever virus, severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) coronavirus infection. To study whether ADE is involved in COVID-19 infections, in vitro pseudotyped SARS-CoV-2 entry into Raji cells, K562 cells, and primary B cells mediated by plasma from recovered COVID-19 patients were employed as models. The enhancement of SARS-CoV-2 entry into cells was more commonly detected in plasma from severely-affected elderly patients with high titers of SARS-CoV-2 spike protein-specific antibodies. Cellular entry was mediated via the engagement of FcγRII receptor through virus-cell membrane fusion, but not by endocytosis. Peptide array scanning analyses showed that antibodies which promote SARS-CoV-2 infection targeted the variable regions of the RBD domain. To further characterize the association between the spike-specific antibody and ADE, an RBD-specific monoclonal antibody (7F3) was isolated from a recovered patient, which potently inhibited SARS-Cov-2 infection of ACE-2 expressing cells and also mediated ADE in Raji cells. Site-directed mutagenesis the spike RBD domain reduced the neutralization activity of 7F3, but did not abolish its binding to the RBD domain. Structural analysis using cryo-electron microscopy (Cryo-EM) revealed that 7F3 binds to spike proteins at a shift-angled pattern with one “up” and two “down” RBDs, resulting in partial overlapping with the receptor binding motif (RBM), while a neutralizing monoclonal antibody that lacked ADE activity binds to spike proteins with three “up” RBDs, resulting in complete overlapping with RBM. Our results revealed that ADE mediated by SARS-CoV-2 spike-specific antibodies could result from binding to the receptor in slightly different pattern from antibodies mediating neutralizations. Studies on ADE using antibodies from recovered patients via cell biology and structural biology technology could be of use for developing novel therapeutic and preventive measures for control of COVID-19 infection.

Background The COVID-19 pandemic caused by SARS-CoV-2 coronavirus threatens global public health. Currently, neutralizing antibodies (NAbs) versus this virus are expected to correlate with recovery and protection of this disease. However, the characteristics of these antibodies have not been well studied in association with the clinical manifestations in patients. Methods Plasma collected from 175 COVID-19 recovered patients with mild symptoms were screened using a safe and sensitive pseudotyped-lentiviral-vector-based neutralization assay. Spike-binding antibody in plasma were determined by ELISA using RBD, S1, and S2 proteins of SARS-CoV-2. The levels and the time course of SARS-CoV-2-specific NAbs and the spike-binding antibodies were monitored at the same time. Findings SARS-CoV-2 NAbs were unable to cross-reactive with SARS-CoV virus. SARS-CoV-2-specific NAbs were detected in patients from day 10-15 after the onset of the disease and remained thereafter. The titers of NAb among these patients correlated with the spike-binding antibodies targeting S1, RBD, and S2 regions. The titers of NAbs were variable in different patients. Elderly and middle-age patients had significantly higher plasma NAb titers (P<0.0001) and spike-binding antibodies (P=0.0003) than young patients. Notably, among these patients, there were ten patients whose NAb titers were under the detectable level of our assay (ID50: < 40); while in contrast, two patients, showed very high titers of NAb, with ID50 :15989 and 21567 respectively. The NAb titers were positive correlated with plasma CRP levels but negative correlated with the lymphocyte counts of patients at the time of admission, indicating an association between humoral response and cellular immune response. Interpretation The variations of SARS-CoV-2 specific NAbs in recovered COVID-19 patients may raise the concern about the role of NAbs on disease progression. The correlation of NAb titers with age, lymphocyte counts, and blood CRP levels suggested that the interplay between virus and host immune response in coronavirus infections should be further explored for the development of effective vaccine against SARS-CoV-2 virus. Furthermore, titration of NAb is helpful prior to the use of convalescent plasma for prevention or treatment. Funding Ministry of Science and Technology of China, National Natural Science Foundation of China, Shanghai Municipal Health Commission, and Chinese Academy of Medical Sciences

Abstract Limb ischemia reperfusion (LIR) can activate endogenous cytoprotective mechanisms by generating specific proteins against reperfusion injury in remote organs. The present study investigated the roles of heme oxygenase‐1 (HO‐1) pathway and the molecular mechanisms underlying the regulation of this pathway on lung injury following LIR. LIR was induced by ischemia for 4 hours followed by reperfusion for 6 hours (LIR 6 hours) or 16 hours (LIR 16 hours) in male Sprague‐Dawley rats. HO‐1 inducer cobalt protoporphyrin (Copp) or HO‐1 inhibitor zinc protoporphyrin (Znpp) was intravenously injected 24 hours before ischemia. The animals were randomly divided into nine groups, including normal control, LIR 6 hours, LIR 16 hours, Copp, Copp + LIR 6 hours, Copp + LIR 16 hours, and Znpp, Znpp+ LIR 6 hours, and Znpp + LIR 16 hours groups (each group included four samples). Lung injury was examined through histopathology. Quantitative real‐time PCR, immunohistochemistry and Western blot were applied to detect the mRNA and protein levels of HO‐1, Nrf2, and Bach1. Our study showed that LIR induced Nrf2 upregulation but Bach1 downregulation to promote HO‐1 expression in lung tissues. Activation of HO‐1 pathway by Copp potentially enhanced Nrf2 expression but inhibition of the pathway by Znpp promoted Bach1 expression. Inducer of HO‐1 pathway, Copp injection improved the lung injury. Nevertheless, Znpp injection aggravated the lung injury following LIR. Our findings suggested that activated HO‐1 pathway might exert protective effects on the lung injury following LIR.

The prodrug strategy serves well in drug formulation and delivery. Two disulfide-based PEGylated prodrugs were developed and the drug reconversion upon different conditions were studied in detail. The reconversion-induced oversaturation phenomenon was firstly reported here. We found the prodrug can co-assemble with parent drug via π-π stacking into well-defined nanoparticles. The PEG layer of the self-assembled nanoparticles improved the stability of the PEGylated prodrug by reducing the contact with biological enzymes. The nanoparticles also show favorable antitumor efficacy, both in vitro and in vivo.

To analyze the dynamic changes of serum metabolomics in wasp sting victims, we collected serum from 10 healthy volunteers and 10 patients who had been stung 3 hours, 24 hours, and 72 hours before sample collection. We analyzed the metabolomics by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) techniques and then performed enrichment analysis. A total of 838 metabolites were identified. Serum metabolomics analysis using MetaboAnalyst revealed 289 metabolites that were significantly different among patients in the 3-hour group versus healthy controls (P<0.001). Pathway analysis of those metabolites indicated that those metabolic sets were associated with sphingolipid metabolism. Based on the differences among the control, 3-hour, 24-hour, and 72-hour groups, we classified serum metabolites into different categories. The first and second categories included 297 and 280 metabolites that were significantly different in terms of concentration among healthy controls versus the participants whose sera were analyzed 3 hours, 24 hours, and 72 hours after wasp stings. Pathway analysis of those metabolites indicated that those metabolic sets were associated with thiamine metabolism. The third category included 269 significant metabolites. The fourth category included 28 significant metabolites. Pathway analysis of the metabolites in third and fourth categories indicated that those metabolic sets were associated with phenylalanine, tyrosine, and tryptophan biosynthesis. The fifth category included 31 metabolites, which were not significantly different between the control and 3-hour groups but were higher in concentration in the 24-hour and 72-hour groups. Pathway analysis of the fifth category of significant metabolites identified linoleic acid metabolism. In conclusion, multiple metabolic pathways are associated with wasp stings, and these might provide a basis for exploring mechanisms of wasp sting injury and potential targets for therapy.

Objective: Wasp venom is a potentially important natural drug, but it can cause hypersensitivity reactions. The purpose of the present study was to systematically study the epitopes of wasp venom. Methods: Using a random 12-peptide phage library, we performed antibody-binding epitope panning on ten serum samples from wasp sting victims at 3 h and 4 days after the sting. The panning epitopes were identified by high-throughput sequencing and matched with wasp venom proteins by BLAST. The panned antibody-binding epitopes were verified by ELISA. Results: A total of 35 specific potential wasp venom epitopes in 4 days were identified. Amongst them, twelve peptide epitopes were matched with nine wasp venom proteins, namely, vitellogenin precursor, hexamerin 70b precursor, venom carboxylesterase-6 precursor, MRJP5, major royal jelly protein 8 precursor, venom acid phosphatase Acph-1 precursor, phospholipase A2, venom serine protease 34 precursor, and major royal jelly protein 9 precursor. The changes in serum IgM antibodies induced by wasp venom were confirmed by ELISA based on the 12 peptide epitopes. Conclusion: The nine wasp venom proteins are potential allergens, which should be excluded or modified in the potential biomedical applications of wasp venom.

Antibody-dependent cell-mediated cytotoxicity bridges humoral immunity and cellular immunity. Thus vaccine candidates which can elicit both broadly neutralizing antibodies and potent antibody-dependent cell-mediated cytotoxicity (ADCC) are recommended. Previously, a panel of functional epitopes that can elicit ADCC effects is isolated and characterized on the H1N1 Influenza Virus. Based on these identified epitopes, an epitope vaccine against H1N1 infection has been designed. The serum of vaccine immunized mice show potent ADCC activities in comparison with vector control group and HA ecto domain vaccinated group. However, the release of IL-6 and TNFα is higher in lung of epitope vaccine immunized mice. The viral load is also higher in epitope vaccine immunized mice. In addition, the epitope vaccine immunized mice showed lower survive rate than both empty vector immunized mice and HA ectodomain immunized mice. Passive transfer of serum from epitope vaccine immunized mice to healthy adult mice can decrease the survival rate of recipients after viral challenge. Our data suggested that ADCC epitope based vaccine has a mortality promoting effect rather than protective effect after H1N1 viral challenge. This result provides indications in future vaccine design with a consideration of balancing humoral immune response and cellular immune response.