Background/Objectives: Since 2022, outbreaks of monkeypox have raised widespread concern and have been declared a public health emergency of international concern by the World Health Organization. There is an urgent need to develop a safe and effective vaccine against the monkeypox virus (MPXV). Recombinant protein vaccines play a significant role in the prevention of infectious diseases due to their high safety and efficacy. Methods: We used the A29, E8, M1, A35, and B6 proteins of MPXV as candidate antigens to generate a panel of multi-component MPXV vaccine candidates, which were administered subcutaneously to immunize mice. Results: The results showed that the vaccine candidates Mix-AEM, Mix-AEMA, Mix-AEMB, and Mix-AEMAB effectively elicited strong neutralizing antibody responses and demonstrated significant protection against vaccinia virus (VACV) infection in a murine model. The vaccine candidate Mix-AEM induced significantly higher levels of neutralizing antibodies, cellular immunity capacity, and virus clearance compared to the vaccine candidate Mix-AE (lacking M1). Single-component immunization showed that M1 induced higher levels of neutralizing antibodies than A29 and E8. These results indicated that M1 is a critical and essential antigen in the MPXV vaccine. The number of cells secreting IFN-γ was significantly increased in the Mix-AEMA and Mix-AEMAB groups compared to the A35-deficient vaccine candidates, demonstrating the important role of A35 in inducing IFN-γ secreting. In addition, the neutralizing antibodies induced by these multi-component vaccine candidates were maintained at high levels six months after the third immunization. Conclusions: In summary, this study lays the groundwork for combining antigens to develop multi-component subunit vaccines.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariants raises concerns regarding the effectiveness of immunity acquired from previous Omicron subvariants breakthrough infections (BTIs) or reinfections (RIs) against the current circulating Omicron subvariants. In this study, we prospectively investigate the dynamic changes of virus-specific antibody and T cell responses among 77 adolescents following Omicron BA.2.3 BTI with or without subsequent Omicron BA.5 RI. Notably, the neutralizing antibodies (NAbs) titers against various detected SARS-CoV-2 variants, especially the emerging Omicron CH.1.1, XBB.1.5, XBB.1.16, EG.5.1, and JN.1 subvariants, exhibited a significant decrease along the time. A lower level of IgG and NAbs titers post-BTI was found to be closely associated with subsequent RI. Elevated NAbs levels and shortened antigenic distances were observed following Omicron BA.5 RI. Robust T cell responses against both Omicron BA.2- and CH.1.1-spike peptides were observed at each point visited. The exposure to Omicron BA.5 promoted phenotypic differentiation of virus-specific memory T cells, even among the non-seroconversion adolescents. Therefore, updated vaccines are needed to provide effective protection against newly emerging SARS-CoV-2 variants among adolescents.

The emergence of novel Omicron subvariants has raised concerns regarding the efficacy of immunity induced by prior Omicron subvariants breakthrough infection (BTI) or reinfection against current circulating Omicron subvariants. Here, we prospectively investigated the durability of antibody and T cell responses in individuals post Omicron BA.2.2 BTI, with or without subsequent Omicron BA.5 reinfection. Our findings reveal that the emerging Omicron subvariants, including CH.1.1, XBB, and JN.1, exhibit extensive immune evasion induced by previous infections. Notably, the level of IgG and neutralizing antibodies were found to correlate with subsequent Omicron BA.5 reinfection. Fortunately, T cell responses recognizing both Omicron BA.2 and CH.1.1 peptides were observed. Furthermore, Omicron BA.5 reinfection may alleviate immune imprinting induced by WT-vaccination, bolster virus-specific ICS+ T cell responses, and promote the phenotypic differentiation of virus-specific memory CD8+ T cells. Antigen-updated or T cell-conserved vaccines are needed to control the transmission of diverse emerging SARS-CoV-2 variants.

Preclinical studies indicate that SARS-CoV-2 nucleocapsid (N)-based vaccines, along with other viral protein(s), confer protection in various animal models against infection by SARS-CoV-2 ancestral virus and variants of concern. However, the optimal vaccination procedure and the role of N-specific host adaptive immune responses remain elusive. Here, we report that intranasal inoculation with replication-deficient human adenovirus type 5 expressing SARS-CoV-2 N protein (Ad5-N) conferred no protection in the lung of female BALB/c mice upon re-encountering the antigen, either by 10-fold Ad5-N re-exposure or sublethal infection of mouse-adapted SARS-CoV-2. By contrast, this procedure led to aggravated lung pathology with more necroptotic CD3+ T cells and Ly6G+ granulocytes, which was associated with the accumulation of IFN-γ-expressing antigen-experienced CD4+ and CD8+ T cells. These findings pre-caution the clinical application of this vaccination procedure. Furthermore, our data suggest that excessive host adaptive immune responses against N protein contributes to COVID-19 pathogenesis.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission is responsible for the coronavirus disease 2019 (COVID-19) pandemic. SARS-CoV-2 uses the angiotensin-converting enzyme 2 (ACE2) receptor to enter the host, and the gastrointestinal tract is a potential infection site as this receptor is expressed on it. Multiple studies have indicated that an increasing number of COVID-19 patients presented with gastrointestinal symptoms that are highly associated with disease severity. Moreover, emerging evidence has demonstrated that alterations in the gut immune microenvironment induced by intestinal SARS-CoV-2 infection can regulate respiratory symptoms. Therefore, targeting the intestines may be a candidate therapeutic strategy in patients with COVID-19; however, no mouse model can serve as an appropriate infection model for the development of fatal pneumonia while mimicking intestinal infection. In this study, a novel human ACE2 knock-in (KI) mouse model (or hACE2-KI) was systemically compared with the popular K18-hACE2 mice; it showed differences in the distribution of lung and intestinal infections and pathophysiological characteristics. These newly generated hACE2-KI mice were susceptible to intranasal infection with SARS-CoV-2, and not only developed mild to severe lung injury, but also acquired intestinal infection. Consequently, this model can be a useful tool for studying intestinal SARS-CoV-2 infection and developing effective therapeutic strategies.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel subset of coronavirus that causes coronavirus disease 2019 (COVID-19), but vaccine development is hampered by the high mutation of virus This article is protected by copyright. All rights reserved.

Acinetobacter baumannii has been listed as one of the most critical pathogens in nosocomial infections; however, the key genes and mechanisms to adapt to the host microenvironment lack in-depth understanding. In this study, a total of 76 isolates (from 8 to 12 isolates per patient, spanning 128 to 188 days) were longitudinally collected from eight patients to investigate the within-host evolution of A. baumannii. A total of 70 within-host mutations were identified, 80% of which were nonsynonymous, indicating the important role of positive selection. Several evolutionary strategies of A. baumannii to increase its potential to adapt to the host microenvironment were identified, including hypermutation and recombination. Six genes were mutated in isolates from two or more patients, including two TonB-dependent receptor genes (bauA and BJAB07104_RS00665). In particular, the siderophore receptor gene bauA was mutated in multiple isolates from four patients with three MLST types, and all mutations were at amino acid 391 in ligand-binding sites. With 391T or 391A, BauA was more strongly bound to siderophores, which promoted the iron-absorption activity of A. baumannii at acidic or neutral pH, respectively. Through the A/T mutation at site 391 of BauA, A. baumannii displayed two reversible phases to adapt to distinct pH microenvironments. In conclusion, we demonstrated the comprehensive within-host evolutionary dynamics of A. baumannii, and discovered a key mutation of BauA site 391 as a genetic switch to adapt to different pH values, which may represent a model in the pathogen evolutionary adaption of the host microenvironment.

AbstractBackgroundTo determine an appropriate dose of, and immunization schedule for, a vaccine SCoK against COVID‐19 for an efficacy study; herein, we conducted randomized controlled trials to assess the immunogenicity and safety of this vaccine in adults.MethodsThese randomized, double‐blind, placebo‐controlled phase 1 and 2 trials of vaccine SCoK were conducted in Binhai District, Yan City, Jiangsu Province, China. Younger and older adult participants in phase 1 and 2 trials were sequentially recruited into different groups to be intramuscularly administered 20 or 40 μg vaccine SCoK or placebo. Participants were enrolled into our phase 1 and 2 studies to receive vaccine or placebo.ResultsNo serious vaccine‐related adverse events were observed in either trial. In both trials, local and systemic adverse reactions were absent or mild in most participants. In our phase 1 and 2 studies, the vaccine induced significantly increased neutralizing antibody responses to pseudovirus and live SARS‐CoV‐2. The vaccine induced significant neutralizing antibody responses to live SARS‐CoV‐2 on day 14 after the last immunization, with NT50s of 80.45 and 92.46 in participants receiving 20 and 40 μg doses, respectively; the seroconversion rates were 95.83% and 100%. The vaccine SCoK showed a similar safety and immunogenicity profiles in both younger participants and older participants. The vaccine showed better immunogenicity in phase 2 than in phase 1 clinical trial. Additionally, the incidence of adverse reactions decreased significantly in phase 2 clinical trial. The vaccine SCoK was well tolerated and immunogenic.

COVID-19 has spread around the world and caused serious public health and social problems. Although several vaccines have been authorized for emergency use, new effective antiviral drugs are still needed. Some repurposed drugs including Chloroquine, Hydroxychloroquine and Remdesivir were immediately used to treat COVID-19 after the pandemic. However, the therapeutic effects of these drugs have not been fully demonstrated in clinical studies. In this paper, we found an antimalarial drug, Naphthoquine, showed good broad-spectrum anti-coronavirus activity. Naphthoquineinhibited HCoV-229E, HCoV-OC43 and SARS-CoV-2 replication in vitro, with IC50 = 2.05 ± 1.44 μM, 5.83 ± 0.74 μM, and 2.01 ± 0.38 µM, respectively. Time-of-addition assay was also performed to explore at which stage Naphthoquine functions during SARS-CoV-2 replication. The results suggested that Naphthoquine may influence virus entry and post-entry replication. Considering the safety of Naphthoquine was even better than that of Chloroquine, we think Naphthoquine has the potential to be used as a broad-spectrum drug for coronavirus infection.

Dendritic cell (DC) vaccines are used for cancer and infectious diseases, albeit with limited efficacy. Modulating the formation of DC-T-cell synapses may greatly increase their efficacy. The effects of graphene oxide (GO) nanosheets on DCs and DC-T-cell synapse formation are evaluated. In particular, size-dependent interactions are observed between GO nanosheets and DCs. GOs with diameters of >1 µm (L-GOs) demonstrate strong adherence to the DC surface, inducing cytoskeletal reorganization via the RhoA-ROCK-MLC pathway, while relatively small GOs (≈500 nm) are predominantly internalized by DCs. Furthermore, L-GO treatment enhances DC-T-cell synapse formation via cytoskeleton-dependent membrane positioning of integrin ICAM-1. L-GO acts as a "nanozipper," facilitating the aggregation of DC-T-cell clusters to produce a stable microenvironment for T cell activation. Importantly, L-GO-adjuvanted DCs promote robust cytotoxic T cell immune responses against SARS-CoV-2 spike 1, leading to >99.7% viral RNA clearance in mice infected with a clinically isolated SARS-CoV-2 strain. These findings highlight the potential value of nanomaterials as DC vaccine adjuvants for modulating DC-T-cell synapse formation and provide a basis for the development of effective COVID-19 vaccines.

There is an urgent need for animal models to study SARS-CoV-2 pathogenicity. Here, we generate and characterize a novel mouse-adapted SARS-CoV-2 strain, MASCp36, that causes severe respiratory symptoms, and mortality. Our model exhibits age- and gender-related mortality akin to severe COVID-19. Deep sequencing identified three amino acid substitutions, N501Y, Q493H, and K417N, at the receptor binding domain (RBD) of MASCp36, during in vivo passaging. All three RBD mutations significantly enhance binding affinity to its endogenous receptor, ACE2. Cryo-electron microscopy analysis of human ACE2 (hACE2), or mouse ACE2 (mACE2), in complex with the RBD of MASCp36, at 3.1 to 3.7 Å resolution, reveals the molecular basis for the receptor-binding switch. N501Y and Q493H enhance the binding affinity to hACE2, whereas triple mutations at N501Y/Q493H/K417N decrease affinity and reduce infectivity of MASCp36. Our study provides a platform for studying SARS-CoV-2 pathogenesis, and unveils the molecular mechanism for its rapid adaptation and evolution.

The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) continues to infect people globally. The increased COVID-19 cases and no licensed vaccines highlight the need to develop safe and effective vaccines against SARS-CoV-2 infection. Multiple vaccines candidates are under pre-clinical or clinical trails with different strengths and weaknesses. Here we developed a pilot scale production of a recombinant subunit vaccine (RBD-Fc Vacc) with the Receptor Binding Domain of SARS-CoV-2 S protein fused with the Fc domain of human IgG1. RBD-Fc Vacc induced SARS-CoV-2 specific neutralizing antibodies in non-human primates and human ACE2 transgenic mice. The antibodies induced in macaca fascicularis neutralized three divergent SARS-CoV2 strains, suggesting a broader neutralizing ability. Three times immunizations protected Macaca fascicularis (20ug or 40ug per dose) and mice (10ug or 20ug per dose) from SARS-CoV-2 infection respectively. These data support clinical development of SARS-CoV-2 vaccines for humans. RBD-Fc Vacc is currently being assessed in randomized controlled phase 1/II human clinical trails. Summary This study confirms protective efficacy of a SARS-CoV-2 RBD-Fc subunit vaccine.

研制抗蓖麻毒素精制免疫球蛋白,即马抗蓖麻毒素免疫球蛋白F(ab')2制品,为蓖麻毒素中毒的防治提供特效药.利用传统方法,从蓖麻籽中提取、纯化脱毒蓖麻毒素,加入适量弗氏佐剂充分乳化,免疫马匹,测定免疫马匹血清中和抗体效价并采血,分离血清,按照免疫球蛋白F(ab')2生产工艺制备治疗性抗体成品,并对成品进行中和抗体效力检测、安全性检测及免疫防治效果评价.结果 显示,纯化的蓖麻毒素抗原,经HPLC法测定纯度大于90％,腹腔注射对小鼠的半数致死量(LD50)约为6.38 μg/kg;免疫马匹血清中和抗体效价达1:64000以上时,采血并制备F(ab ')2成品,纯度在80％以上,中和抗体效价均超过6000 U/mL;安全性符合现行《中国药典》要求,对蓖麻毒素中毒动物模型有很好的免疫防治效果.本研究建立了蓖麻毒素精制免疫球蛋白制品生产工艺,制备的成品符合现行《中国药典》要求,为蓖麻毒素中毒的防治提供了新的救命药.

Sensitive, selective, rapid, and label-free detection of pathogenic bacteria with high generality is of great importance for clinical diagnosis, biosecurity, and public health. However, most traditional approaches, such as microbial cultures, are time-consuming and laborious. To circumvent these problems, surface-enhanced Raman spectroscopy (SERS) appears to be a powerful technique to characterize bacteria at the single-cell level. Here, by SERS, we report a strategy for the rapid and specific detection of 22 strains of common pathogenic bacteria. A novel and high-quality silver nanorod SERS substrate, prepared by the facile interface self-assembly method, was utilized to acquire the chemical fingerprint information of pathogens with improved sensitivity. We also applied the mathematical analysis methods, such as the t-test and receiver operating characteristic method, to determine the Raman features of these 22 strains and demonstrate the clear identification of most bacteria (20 strains) from the rest and also the reliability of this SERS sensor. This rapid and specific strategy for wide-range bacterial detection offers significant advantages over existing approaches and sets the base for automated and onsite detection of pathogenic bacteria in a complex real-life situation.

Since the coronavirus disease 2019 (COVID-19) pandemic began, its causative agent, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread worldwide. During the global transmission of SARS-CoV-2, mutations in the viral genome have gradually accumulated and have led to the emergence of variants. These emerging variants, including 501Y.V1, 501Y.V2 and 501Y.V3 (also called the alpha, beta and gamma variants, respectively), rapidly became the predominant epidemic strains and subsequently spread worldwide. All three of these SARS-CoV-2 variants contain specific amino acid mutations in the S protein and share an amino acid mutation, N501Y, in the receptor binding domain (RBD) of the S protein (Fig. S1). The RBD specifically binds to the receptor angiotensin-converting enzyme 2 (ACE2) on human cells and mediates host cell entry of SARS-CoV-2. Interestingly, the N501Y mutation was first documented during in vivo passaging of SARS-CoV-2 in mice (Fig. S1), and the resulting mouse-adapted strains MASCp6 and MASCp36 are fully capable of infecting standard laboratory mice [1,2], unlike isolates of the original SARS-CoV-2 strain. Most importantly, we and others have demonstrated that theN501Ymutation significantly enhances the binding affinity of the SARSCoV-2 RBD for mouse ACE2 [2,3], thus contributing to the acquired infectivity and pathogenicity phenotype in mice. However, whether naturally occurring SARS-CoV-2 variants (501Y.V1, 501Y.V2 and 501Y.V3) that contain this unique N501Y mutation have acquired the capability to infectmice remains to be determined. Herein, we adopt a contemporary 501Y.V2 variant, GDPCC, isolated from an imported case in a patient from South Africa to assay infectivity in mice. The SARS-CoV-2 clinical strain IME-BJ05 (wild-type, WT) isolated in the early stage of the COVID-19 pandemic was used as the control strain.Groups of ninemonth-old female BALB/cmice were intranasally challenged with the 501Y.V2 variant orWTstrain at a doseof 1.2×104 pfu. Remarkably, all 501Y.V2-infected mice began to show ruffled fur, hunched posture and reduced activity on day 3 post infection, and significant weight loss was seen in 501Y.V2-infected mice on days 4–6 post infection (Fig. 1A). The 501Y.V2-infected mice finally recovered, and no deaths occurred during the observation period. However, none of the animals challenged with WT virus developed obvious weight loss or clinical symptoms, as expected. To characterize viral replication dynamics in mice, 501Y.V2or mockinfected animals were sacrificed, and the major tissues and serum were collected. SARS-CoV-2 subgenomic RNA (sgRNA) quantitation showed that the highest abundance of viral RNA was detected in lung tissues from 501Y.V2-infected mice, with an obvious increasing trend during the first two days post infection (Fig. 1B). Viral sgRNA remained detectable in the trachea until day 8 post infection (Fig. 1B). However, no detectable sgRNA was present in other tissues or serum. An in situ hybridization (ISH) assay with the RNAScope approach showed that viral RNA was located mainly in cells along the airway and at the alveolar walls (Fig. 1C). Immunostaining of lung sections showed that SARS-CoV-2 N protein was expressed mainly in bronchiolar epithelial cells and alveolar cells, consistent with the ISH results (Fig. 1D). More importantly, gross necropsy showed visible lung injury, characterized by lung enlargement and local perihilar consolidation, upon 501Y.V2 challenge (Fig. 1E, left panel). Microscopic observation of lung sections from 501Y.V2-infected mice also showed that lung injury occurred mainly in the perihilar region (Fig. 1E, middle panel) and was characterized by large quantities of desquamating necrotic epithelial cells in bronchioles (yellow arrow), scattered hemorrhage (blue arrow) and inflammatory cell infiltration within fused alveolar walls (white arrow)

目的 探究中性粒细胞在蓖麻毒素(Ricin Toxin,RT)致毒过程中的作用,寻找解毒的有效策略.方法 采用10x Genomics单细胞转录组测序技术对中毒小鼠外周血单个核细胞(PBMCs)进行转录组测序及分析,并通过流式细胞术测定目的细胞亚群.结果 经降维聚类、差异基因、拟时序分析结果显示CD177-CD121b+CCRL2+中性粒细胞亚群为RT致毒过程关键亚群,随后通过流式细胞术测定显示该亚群在中毒后6小时在中性粒细胞中的比例显著升高.同时利用CCRL2抗体治疗中毒小鼠其保护率达60％.结论 本研究首次发现在RT中毒后中性粒CD177-CD121b+CCRL2+细胞亚群呈现显著升高,同时CCRL2抗体能够有效保护RT中毒小鼠,为RT致毒机制研究提供新的思路,为其治疗提供新的策略.

采用鸡胚成纤维原代细胞培养痘苗病毒天坛株抗原,甲醛灭活后,利用密度梯度离心法和层析法两步纯化抗原,加入等量ISA206佐剂充分乳化,免疫健康马匹,当中和抗体效价达1∶3 200时,采血,分离血清,按照免疫球蛋白F(ab')2生产工艺制备治疗性抗体成品,并对其进行中和抗体效价、防护效力、安全性检测.结果 显示,鸡胚成纤维原代细胞培养痘苗病毒天坛株滴度均在1.0×107 PFU/mL以上;纯化的抗原纯度在90％以上;纯化的F(ab')2成品,纯度在90％以上,中和抗体效价超过1∶3 200,有很好的免疫防护效力,安全性符合现行《中国药典》要求.结果 表明,建立了马抗天花病毒免疫球蛋白F(ab')2制品生产工艺,制备的成品符合现行《中国药典》要求,为天花治疗提供了新的救命药.

Accumulating studies have shown that long non-coding RNAs (lncRNAs) modulate multiple biological processes, including immune response. However, the underlying mechanisms of lncRNAs regulating host antiviral immune response are not well elucidated. In this study, we report that analysis of the existing dataset transcriptome of blood immune cells of patients with influenza A virus (IAV) infection and after recovery (GSE108807) identified a novel lncRNA, termed as IVRPIE (Inhibiting IAV Replication by Promoting IFN and ISGs Expression), was involved in antiviral innate immunity. In vitro studies showed that IVRPIE was significantly upregulated in A549 cells after IAV infection. Gain-and-loss of function experiments displayed that enforced IVRPIE expression significantly inhibited IAV replication in A549 cells. Conversely, silencing IVRPIE promoted IAV replication. Furthermore, IVRPIE positively regulates the transcription of interferon β1 and several critical interferon-stimulated genes (ISGs), including IRF1, IFIT1, IFIT3, Mx1, ISG15, and IFI44L, by affecting histone modification of these genes. In addition, hnRNP U was identified as an interaction partner for IVRPIE. Taken together, our findings suggested that a novel lncRNA IVRPIE is a critical regulator of host antiviral response.

The ongoing coronavirus disease 2019 (COVID-19) pandemic has prioritized the development of small-animal models for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We adapted a clinical isolate of SARS-CoV-2 by serial passaging in the respiratory tract of aged BALB/c mice. The resulting mouse-adapted strain at passage 6 (called MASCp6) showed increased infectivity in mouse lung and led to interstitial pneumonia and inflammatory responses in both young and aged mice after intranasal inoculation. Deep sequencing revealed a panel of adaptive mutations potentially associated with the increased virulence. In particular, the N501Y mutation is located at the receptor binding domain (RBD) of the spike protein. The protective efficacy of a recombinant RBD vaccine candidate was validated by using this model. Thus, this mouse-adapted strain and associated challenge model should be of value in evaluating vaccines and antivirals against SARS-CoV-2.