Haemorrhagic fever with renal syndrome (HFRS) is a fatal disease caused by Hantaan virus (HTNV) infection. Humoral immunity is essential for effective viral clearance; however, the glycosylation characteristics of immunoglobulin G (IgG) in HFRS patients are not well known. Peripheral blood mononuclear cells from HFRS patients were obtained for B subset analysis using scRNA-seq and flow cytometry. HTNV-specific IgG antibody titers were detected by enzyme-linked immunosorbent assay, and IgG glycosylation was analyzed by ultra-performance liquid chromatography. The proportions of the antibody-secreting memory (ASM) B cells and plasmablasts (PB) were significantly expanded among acute HFRS patients. We discovered significantly increased fucosylated IgG and decreased bisecting N-acetylglucosamine during the convalescent phase of HTNV infection. Meanwhile, positive correlations were observed between ASM subsets and galactosylation/sialylation in the IgG Fc region, and between PB subsets and sialylation. Notably, the glycosylation-related genes, such as RPN1 and RPN2, were primarily expressed differentially in the ASM and PB subclusters, which were enriched in the N-glycosylation modifications of proteins through asparagine. Our findings indicated that IgG N-glycosylation may play a crucial role in combating HTNV infection and contributing to clinical recovery, which provided new insights for optimizing glycoengineered therapeutic antibodies.

IntroductionHuman Enterovirus A71 (EV-A71) is the primary pathogen responsible for severe hand, foot, and mouth disease (HFMD). Vaccination plays a crucial role in controlling its spread. Although inactivated vaccines have been approved, there is growing interest in developing new candidates using advanced platforms. mRNA vaccines, widely used for enveloped viruses, are less studied for non-enveloped viruses like EV-A71. This study investigates the potential of an mRNA vaccine targeting the EV-A71 VP1 protein.MethodsA nucleoside-modified mRNA vaccine encoding the VP1 protein of EV-A71, encapsulated in lipid nanoparticles (LNPs), was developed. Immunogenicity and protective efficacy were evaluated in BALB/c and neonatal A129 mice, respectively. Immune responses were assessed by ELISA, micro-neutralization assays, ELISpot, and intracellular cytokine staining (ICS). Passive protection was tested by transferring immune sera to neonatal mice challenged with EV-A71.ResultsThe VP1 mRNA-LNP vaccine elicited robust humoral and cellular immunity, including high levels of VP1-specific IgG, neutralizing antibodies, and a Th1-biased T-cell response. Notably, the mRNA vaccine outperformed the inactivated vaccine in eliciting cellular immunity. Immune sera provided complete protection against lethal EV-A71 challenge, significantly reducing viral load and pathology.DiscussionThis study demonstrates that the mRNA vaccine exhibits significant potential for combating non-enveloped viruses. These findings highlight the promising role of mRNA platforms in advancing vaccine development against non-enveloped viral pathogens, offering new avenues for future research and clinical applications.

Haemorrhagic fever with renal syndrome (HFRS) is a fatal disease caused by Hantaan virus (HTNV) infection. Humoral immunity is essential for effective viral clearance, but the glycosylation characteristics of immunoglobulin G (IgG) in HFRS patients is not well known. Peripheral blood mononuclear cells from HFRS patients were obtained for B subset analysis using scRNA-seq and flow cytometry. HTNV specific IgG antibody titers were detected by enzyme linked immunosorbent assay, and IgG glycosylation was analyzed by ultra-performance liquid chromatography. The proportions of the antibody-secreting memory (ASM) B cells and plasmablasts (PB) were significantly expanded among acute HFRS patients. We discovered significantly increased fucosylated IgG and decreased bisecting N-acetylglucosamine during the convalescent phase of HTNV infection. However, positive correlations were observed between ASM subsets and galactosylation/sialylation in the IgG Fc region, and between PB subsets and sialylation. Notably, the glycosylation-related genes were primarily differentially expressed in the ASM and PB subclusters, such as PRN1 and PRN2 , which were enriched in the N-glycosylation modifications of proteins through asparagine. Our findings indicated that IgG N-glycosylation may play a crucial role in combating HTNV infection and contributing to clinical recovery, which provided new insights for optimizing glycoengineered therapeutic antibodies. ### Competing Interest Statement The authors have declared no competing interest.

ABSTRACT Although severe fever with thrombocytopenia syndrome (SFTS) was first described in China in 2009, the case fatality rate remains >40% among patients with multi-organ failure. To date, no antivirals specifically targeting SFTSV have been approved. We obtained several monoclonal antibodies (mAbs) from SFTS survivors by single-cell RNA-seq. Neutralization and animal experiments were applied to assess the effects of these mAbs in vitro and in vivo , and co-crystal structures with SFTSV-Gn glycoproteins were determined by X-ray crystallography. The mAbs SD4, SD12, and SD22 targeted the SFTSV-Gn with high neutralizing activities, and, remarkably, SD4 and SD22 exhibited K D values in the range of 32–83 pM for different viral genotypes. Notably, a single administration (20 mg/kg) of SD4 and SD22 showed 100% protection in mice at day 3 post-inoculation (dpi). Importantly, SD4 also provided 60% protection at a lower dose (0.3 mg/kg) when administered at 3 dpi. The crystallographic structures of SD4, SD22, and SD12 with Gn were determined at 3.3 Å, 2.8 Å, and 2.4 Å, respectively, which revealed that they recognized a conserved antigenic epitope around the hexon wellhead edge. These human-derived mAbs have significant therapeutic potential for severe SFTS cases and provide a basis for rational antibody-based vaccine designs and clinical trials. IMPORTANCE The incidence of severe fever with thrombocytopenia syndrome (SFTS) has been increasing in Asia in recent years; however, no specific antiviral agents have been approved to date. Herein, we report a panel of anti-SFTSV Gn monoclonal antibodies (mAbs) with excellent neutralizing capacities and remarkable therapeutic potential in vitro and in vivo in a mouse model. In addition, crystallographic structures of mAbs complexed with Gn were resolved with atomic resolution (2.4 Å–3.3 Å), revealing a conserved antigenic epitope near the hexon wellhead edge. In sum, the neutralizing antibodies reported in the present study have significant therapeutic potential, paving the way for effective treatment of severe SFTS patients.

We isolated severe fever with thrombocytopenia syndrome virus (SFTSV) from farmed minks in China, providing evidence of natural SFTSV infection in farmed minks. Our findings support the potential role of farmed minks in maintaining SFTSV and are helpful for the development of public health interventions to reduce human infection.

The impairment of antibody-mediated immunity is a major factor associated with fatal cases of severe fever with thrombocytopenia syndrome (SFTS). By collating the clinical diagnosis reports of 30 SFTS cases, we discovered the overprolifera-tion of monoclonal plasma cells (MCP cells, CD38+cLambda+cKappa-) in bone marrow, which has only been reported previously in multiple myeloma. The ratio of CD38+cLambda+ versus CD38+cKappa+ in SFTS cases with MCP cells was significantly higher than that in normal cases. MCP cells presented transient expression in the bone marrow, which was distinctly different from multiple myeloma. Moreover, the SFTS patients with MCP cells had higher clinical severity. Further, the overproliferation of MCP cells was also observed in SFTS virus (SFTSV)-infected mice with lethal infectious doses. Together, SFTSV infec-tion induces transient overproliferation of monoclonal lambda-type plasma cells, which have important implications for the study of SFTSV pathogenesis, prog-nosis, and the rational development of therapeutics.

Fever with thrombocytopenia syndrome is usually an acute new infectious disease caused by the infection of fever with thrombocytopenia syndrome virus after being bitten by ticks.It has been reported in many cities in China and abroad.According to research statistics, the case fatality rate can reach 5%~30%. It occurs frequently in spring and summer. It is mainly distributed in rural areas in mountainous and hilly areas. In viral infectious diseases, the body often shows impaired function of the immune system, which leads to a series of abnormal pathophysiological changes. This article reviews the related studies on abnormal changes of immune cells, immune molecules and bone marrow detection in patients with fever and thrombocytopenia syndrome, in order to increase the understanding of relevant staff, and then promote the in-depth research on the relevant mechanism of the disease and the research and innovation of new diagnosis and treatment technology.

发热伴血小板减少综合征(SFTS)是主要以发热伴血小板减少为特征的一种急性传染病.临床常表现为多个器官受累,重症患者主要表现为高热、神经系统症状、出血性症状及肺部症状等.实验室检查方面,重症患者血常规、生化酶学、凝血功能、免疫系统和细胞因子出现明显异常,同时SFTS患者骨髓穿刺可见嗜血细胞综合征现象.重症患者病情进展快、预后差,病死率较高,且该疾病缺乏特效治疗药物.因此,早期识别重症患者并给予对症支持治疗,对降低病死率尤为重要.本文就重症发热伴血小板减少综合征的临床特征展开综述,以期为重症SFTS患者早期识别及治疗提供新思路.

The detailed features and the longitudinal variation of influenza-specific T cell responses within naturally infected patients and the relationship with disease severity remain uncertain. In this study, we characterized the longitudinal influenza-specific CD4+ and CD8+ T cell responses, T cell activation, and migration-related cytokine/chemokine secretion in pH1N1-infected patients with or without viral pneumonia with human PBMCs. Both the influenza-specific CD4+ and CD8+ T cells presented higher responses in patients with severe infection than in mild ones, but with distinct longitudinal variations, phenotypes of memory markers, and immune checkpoints. At 7 ± 3 d after onset of illness, effector CD8+ T cells (CD45RA+CCR7-) with high expression of inhibitory immune receptor CD200R dominated the specific T cell responses. However, at 21 ± 3 d after onset of illness, effector memory CD4+ T cells (CD45RA-CCR7-) with high expression of PD1, CTLA4, and LAG3 were higher among the patients with severe disease. The specific T cell magnitude, T cell activation, and migration-related cytokines/chemokines possessed a strong connection with disease severity. Our findings illuminate the distinct characteristics of immune system activation during dynamic disease phases and its correlation with lung injury of pH1N1 patients.

Purpose Chlamydia psittaci ( C. psittaci ) has caused sporadic, but recurring, fatal community-acquired pneumonia outbreaks worldwide, posing a serious threat to public health. Our understanding of host inflammatory responses to C. psittaci is limited, and many bronchitis cases of psittaci have rapidly progressed to pneumonia with deterioration. Methods To clarify the host inflammatory response in psittacosis, we analyzed clinical parameters, and compared transcriptomic data, concentrations of plasma cytokines/chemokines, and changes of immune cell populations in 17 laboratory-confirmed psittacosis cases, namely, 8 pneumonia and 9 bronchitis individuals, in order to assess transcriptomic profiles and pro-inflammatory responses. Results Psittacosis cases with pneumonia were found to have abnormal routine blood indices, liver damage, and unilateral pulmonary high-attenuation consolidation. Transcriptome sequencing revealed markedly elevated expression of several pro-inflammatory genes, especially interleukins and chemokines. A multiplex-biometric immunoassay showed that pneumonia cases had higher levels of serum cytokines (G-CSF, IL-2, IL-6, IL-10, IL-18, IP-10, MCP-3, and TNF-α) than bronchitis cases. Increases in activated neutrophils and decreases in the number of lymphocytes were also observed in pneumonia cases. Conclusion We identified a number of plasma biomarkers distinct to C. psittaci pneumonia and a variety of cytokines elevated with immunopathogenic potential likely inducing an inflammatory milieu and acceleration of the disease progression of psittaci pneumonia. This enhances our understanding of inflammatory responses and changes in vascular endothelial markers in psittacosis with heterogeneous symptoms and should prove helpful for developing both preventative and therapeutic strategies.

Nonpharmaceutical interventions (NPIs) have been commonly deployed to prevent and control the spread of the coronavirus disease 2019 (COVID-19), resulting in a worldwide decline in influenza prevalence. However, the influenza risk in China warrants cautious assessment. We conducted a cross-sectional, sero-epidemiological study in Shandong Province, Northern China in mid-2021. Hemagglutination inhibition was performed to test antibodies against four influenza vaccine strains. A combination of descriptive and meta-analyses was adopted to compare the seroprevalence of influenza antibodies before and during the COVID-19 pandemic. The overall seroprevalence values against A/H1N1pdm09, A/H3N2, B/Victoria, and B/Yamagata were 17.8% (95% CI 16.2%–19.5%), 23.5% (95% CI 21.7%–25.4%), 7.6% (95% CI 6.6%–8.7%), and 15.0 (95% CI 13.5%–16.5%), respectively, in the study period. The overall vaccination rate was extremely low (2.6%). Our results revealed that antibody titers in vaccinated participants were significantly higher than those in unvaccinated individuals (P < 0.001). Notably, the meta-analysis showed that antibodies against A/H1N1pdm09 and A/H3N2 were significantly low in adults after the COVID-19 pandemic ( P < 0.01). Increasing vaccination rates and maintaining NPIs are recommended to prevent an elevated influenza risk in China.

Abstract Background The longitudinal antigen-specific immunity in COVID-19 convalescents is crucial for long-term protection upon individual re-exposure to SARS-CoV-2, and even more pivotal for ultimately achieving population-level immunity. To better understand the features of immune memory in individuals with different disease severities at one year post-disease onset we conducted this cohort study. Methods We conducted a systematic antigen-specific immune evaluation in 101 COVID-19 convalescents, who had asymptomatic, mild, moderate, or severe disease, through two visits at months 6 and 12 post-disease onset. The SARS-CoV-2-specific antibodies, comprising NAb, IgG, and IgM, were assessed by mutually corroborated assays, i.e. neutralization, enzyme-linked immunosorbent assay (ELISA), and microparticle chemiluminescence immunoassay (MCLIA). Meanwhile, the T-cell memory against SARS-CoV-2 spike, membrane and nucleocapsid proteins was tested through enzyme-linked immunospot assay (ELISpot), intracellular cytokine staining (ICS), and tetramer staining-based flow cytometry, respectively. Results SARS-CoV-2-specific IgG antibodies, and also NAb can persist among over 95% COVID-19 convalescents from 6 months to 12 months after disease onset. At least 19/71 (26%) of COVID-19 convalescents (double positive in ELISA and MCLIA) had detectable circulating IgM antibody against SARS-CoV-2 at 12m post-disease onset. Notably, the percentages of convalescents with positive SARS-CoV-2-specific T-cell responses (at least one of the SARS-CoV-2 antigen S1, S2, M and N protein) were 71/76 (93%) and 67/73 (92%) at 6m and 12m, respectively. Furthermore, both antibody and T-cell memory levels of the convalescents were positively associated with their disease severity. Conclusions SARS-CoV-2-specific cellular and humoral immunities are durable at least until one year after disease onset.

Background. The longitudinal antigen-specific immunity in COVID-19 convalescents is crucial for long-term protection upon individual re-exposure to SARS-CoV-2, and even more pivotal for ultimately achieving population-level immunity. We conducted this cohort study to better understand the features of immune memory in individuals with different disease severities at 1 year post-disease onset. Methods. We conducted a systematic antigen-specific immune evaluation in 101 COVID-19 convalescents, who had asymptomatic, mild, moderate, or severe disease, through 2 visits at months 6 and 12 after disease onset. The SARS-CoV-2-specific antibodies, comprising neutralizing antibody (NAb), immunoglobulin (Ig) G, and IgM, were assessed by mutually corroborated assays (ie, neutralization, enzyme-linked immunosorbent assay [ELISA], and microparticle chemiluminescence immunoassay [MCLIA]). Meanwhile, T-cell memory against SARS-CoV-2 spike, membrane, and nucleocapsid proteins was tested through enzyme-linked immunospot assay (ELISpot), intracellular cytokine staining, and tetramer staining-based flow cytometry, respectively. Results. SARS-CoV-2-specific IgG antibodies, and NAb, can persist among >95% of COVID-19 convalescents from 6 to 12 months after disease onset. At least 19/71 (26%) of COVID-19 convalescents (double positive in ELISA and MCLIA) had detectable circulating IgM antibody against SARS-CoV-2 at 12 months post-disease onset. Notably, numbers of convalescents with positive SARS-CoV-2-specific T-cell responses (>= 1 of the SARS-CoV-2 antigen S1, S2, M, and N proteins) were 71/76 (93%) and 67/73 (92%) at 6 and 12 months, respectively. Furthermore, both antibody and T-cell memory levels in the convalescents were positively associated with disease severity. Conclusions. SARS-CoV-2-specific cellular and humoral immunities are durable at least until 1 year after disease onset.

目的 肠道病毒71型(enterovirus 71,EV71)是引起重症手足口病的主要病原体,目前缺少有效的抗病毒药物.本研究利用EV71 VP1蛋白作为抗原,筛选免疫小鼠脾脏特异性表达EV71抗体的B细胞.方法 将EV71 VP1基因进行密码子优化,构建至pET-21a(+)表达载体,并转化到大肠埃希菌BL21-DE3,优化蛋白表达和复性条件,经SDS-PAGE和Western blot鉴定表达,并检测其抗原性;以纯化蛋白为抗原,通过流式细胞术对灭活病毒免疫小鼠的B淋巴细胞进行分选,用于单克隆抗体的制备.结果 EV71 VP1基因在大肠埃希菌中以包涵体形式稳定表达,纯化复性后的蛋白具有良好的免疫原性;利用表达的VP1蛋白从免疫和未免疫的昆明小鼠脾脏筛选出能够特异性表达EV71抗体的B细胞,两者数量差异具有统计学意义.结论 成功获得免疫原性良好的EV71 VP1重组蛋白,与流式细胞术结合可用于EV71特异B细胞的检测和分选.

病毒是一类个体细微,结构简单,只含有一种核酸,依赖于宿主细胞以复制方式进行繁殖的非细胞型微生物,也是一种独特的传染因子.对于病毒引起的感染性疾病目前临床尚缺乏特效疗法,为解决这一难题,不少人将目光投向我国传统中草药.相较于西药,中药具有许多得天独厚的优势,诸如药性温和,毒性较低,价格低廉,材料丰富等.本文将针对中药治疗病毒中常见种类:流感病毒、乙型肝炎病毒、柯萨奇病毒、呼吸道合胞病毒、腺病毒展开讨论.

Haemorrhagic fever with renal syndrome (HFRS) following Hantaan virus (HTNV) infection displays variable clinical signs. Humoral responses elicited during HTNV infections are considered important, however, this process remains poorly understood. Herein, we have investigated the phenotype, temporal dynamics, and characteristics of B-cell receptor (BCR) repertoire in an HFRS cohort. The serological profiles were characterized by a lowered expression level of nucleoprotein (NP)-specific antibody in severe cases. Importantly, B-cell subsets were activated and proliferated within the first two weeks of symptom onset and moderate cases reacted more rapidly. BCR analysis in the recovery phase revealed a dramatic increase in the immunoglobulin gene diversity which was more significantly progressed in moderate infections. In severe cases, B-cell-related transcription was lower with inflammatory sets overactivated. Taken together, these data suggest the clinical signs and disease recovery in HFRS patients were positively impacted by rapid and efficacious humoral responses.

To determine the seroprevalence and seroconversion of avian influenza virus (AIV) antibodies in poultry workers, we conducted a seroepidemiologic study in 7 areas of China during December 2014-April 2016. We used viral isolation and reverse transcription PCR to detect AIVs in specimens from live poultry markets. We analyzed 2,124 serum samples obtained from 1,407 poultry workers by using hemagglutination inhibition and microneutralization assays. We noted seroprevalence of AIV antibodies for subtypes H9N2, H7N9, H6N1, H5N1-SC29, H5N6, H5N1-SH199, and H6N6. In serum from participants with longitudinal samples, we noted seroconversion, with >4-fold rise in titers, for H9N2, H7N9, H6N1, H5N1-SC29, H6N6, H5N6, and H5N1-SH199 subtypes. We found no evidence of H10N8 subtype. The distribution of AIV antibodies provided evidence of asymptomatic infection. We found that AIV antibody prevalence in live poultry markets correlated with increased risk for H7N9 and H9N2 infection among poultry workers.

There was a substantial increase with infections of H7N9 avian influenza virus (AIV) in humans during Wave 5 (2016-2017). To investigate whether H7N9 had become more infectious/transmissible and pathogenic overall, we characterized the receptor binding and experimentally infected ferrets with highly pathogenic (HP)- and low pathogenic (LP)-H7N9 isolates selected from Wave 5, and compared their pathogenicity and transmissibility with a Wave 1 isolate from 2013. Studies show that A/Anhui/1/2013 (LP) and A/Chicken/Heyuan/16876/2016 (HP) were highly virulent in ferrets, A/Guangdong/Th008/2017 (HP) and A/Chicken/Huizhou/HZ-3/2017 (HP) had moderate virulence and A/Shenzhen/Th001/2016 (LP) was of low virulence in ferrets. Transmission was observed only in ferrets infected with A/Anhui/1/2013 and A/Chicken/Heyuan/16876/2016, consistent with the idea that sicker ferrets had a higher probability to transmit virus to naive animals. Given the Varied virulence and transmissibility observed in circulating H7N9 viruses from Wave 5, we conclude that the current public health risk of H7N9 has not substantially increased compared to 2013 and the circulating viruses are quite diverse.

Objective: The newly emerged highly pathogenic (HP) H7N9 avian influenza virus during Wave Five has caused 28 human infections, while differences in disease severity between low pathogenic (LP)- and HP-H7N9 human infections remain unclear. Methods: Clinical data, concentrations of serum cytokines, dynamics of virus shedding and PaO2/FiO(2) from patients infected with LP-H7N9 (n = 7, LP group) and HP-H7N9 (n = 5, HP group) viruses during Wave Five were compared. In addition, critical mutations associated with H7N9 virulence in mammal/human were analyzed. Results: Lymphopenia, elevated aspartate aminotransferase, alanine aminotransferase, C-reactive protein and lactate dehydrogenase were common features, with higher incidences of leukopenia and thrombocytopenia in the LP group. The acute phase of both groups was accompanied with elevated cytokines associated with disease severity, including MIF, MCP-1 and IP-10. Diffuse exudation of the lungs and consolidation were observed from all patients. The dynamics of virus shedding and PaO2/FiO(2) were similar between both groups. Notably, a higher prevalence of neuraminidase inhibitors (NAIs) resistance in the HP-H7N9 virus was found. Conclusions: Our results indicate that this newly emerged HP-H7N9 virus caused similar disease severity in humans compared with LP-H7N9 virus, while higher case fatality rate and prevalence of NAI-resistance in human HP-H7N9 infections were of great concern. (C) 2019 Published by Elsevier Ltd on behalf of The British Infection Association.