Rabies remains a critical global health concern, particularly in endemic regions where timely access to postexposure prophylaxis (PEP) is often limited. The effectiveness of PEP relies heavily on rabies immune globulin (RIG), yet plasma-derived products continue to face persistent issues of limited supply, variable potency, and high cost. These constraints have intensified the demand for recombinant monoclonal antibodies (mAbs) that provide consistent quality and scalable production. Here, we describe the development of a fully human mAb, H81L90, directed against the rabies virus glycoprotein (RABV-G). The antibody was isolated from a phage-display library constructed using peripheral blood mononuclear cells (PBMCs) from vaccinated donors. H81L90 exhibited strong, specific binding to native RABV-G with nanomolar affinity as determined by surface plasmon resonance (SPR) analysis. In cell-based neutralization assays, H81L90 efficiently blocked infection by the ERA-enhanced green fluorescent protein (EGFP) strain, achieving complete viral inhibition at low microgram concentrations. Protective efficacy was subsequently evaluated in a murine challenge model, where a single intramuscular injection of H81L90 conferred full survival when administered before or at the time of viral exposure and retained measurable activity at reduced doses postexposure. Histopathological assessment revealed substantially lower viral antigen in hippocampal tissue from treated animals, indicating suppression of early neuroinvasion. Collectively, these data establish H81L90 as a potent, fully human antibody with both preventive and postexposure prophylactic potential, supporting its continued development as a next-generation biologic to complement or replace current RIG formulations in rabies PEP.

Background: Rabies is a highly fatal zoonotic disease that causes approximately 59,000 human deaths worldwide each year. Current inactivated rabies vaccines require multiple doses and are associated with high costs. The full-length rabies virus glycoprotein (RVG), a membrane protein, exhibits substantial instability in its trimeric structure during recombinant expression. This instability makes it difficult to obtain high-purity, correctly folded antigens. Objectives: This study focuses on the preparation of a full-length recombinant RVG subunit vaccine candidate expressed in a glycoengineered Pichia pastoris system with mammalian-like glycosylation. Methods: The full-length RVG gene (including the transmembrane domain and cytoplasmic tail) from the Challenge Virus Standard-11 (CVS-11) strain was codon-optimized and inserted into the pPICZαA vector to construct the recombinant expression plasmid pPICZαA-RVG. The plasmid was transformed into glycoengineered Pichia pastoris X33-7 (low-mannose type) by electroporation for inducible expression. The target protein was purified by nickel affinity chromatography, anion-exchange chromatography, and Superdex-200 size-exclusion chromatography. The structural characteristics of the purified protein were analyzed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The purified antigen was formulated with the adjuvants AS03 or MF59. BALB/c mice (n = 5 per group) were immunized intramuscularly following a four-dose schedule (days 0, 7, 14, and 28). Antigen-specific IgG antibody titers were measured by ELISA, and neutralizing antibody titers were determined using the rapid fluorescent focus inhibition test (RFFIT). Results: Glycoengineered Pichia pastoris yeast strains expressing wild-type RVG (RVG-WT) or a mutant variant (RVG-M6: R84S, R199S, H270P, R279S, K300S, and R463S) were successfully constructed. The purified RVG antigen formed nanoparticles with an average particle size of approximately 75 nm. Immunized mice generated robust RVG-specific IgG responses, with titers reaching approximately 6.31 × 105 for RVG-WT after the fourth immunization, compared to 3.16 × 103 for RVG-M6 and 5.62 × 103 for the RVG-WT-PEG control. Two weeks after the fourth immunization, RVG-WT formulated with AS03 or MF59 induced significant neutralizing antibody responses compared with the control group (p < 0.0001 and p < 0.01, respectively). The neutralizing antibody titers reached 1:79.43 in the AS03 group and 1:33.11 in the MF59 group, whereas the WT-PEG + AS03 control group showed a low titer of 1:3.72. In contrast, RVG-M6 formulated with MF59 failed to induce detectable neutralizing antibodies (1:3.02). Furthermore, RVG-WT + AS03 induced significantly higher neutralizing antibody responses than the WT-PEG + AS03 control group (p < 0.0001), and a significant difference was also observed between the RVG-WT + MF59 and RVG-M6 + MF59 groups (p < 0.01). Conclusions: The glycoengineered Pichia pastoris expression system successfully produced uniform full-length rabies virus glycoprotein nanoparticles with high purity. When formulated with the AS03 adjuvant, RVG-WT induced high-titer neutralizing antibodies in mice, suggesting a promising strategy for the development of recombinant subunit vaccines against rabies. However, this study is limited by the absence of challenge studies and validation in target animal species, which will be further investigated in future work.

Introduction:Rabies is a worldwide epidemic that poses a serious threat to global public health. At present, rabies in domestic dogs, cats, and some pets can be effectively prevented and controlled by intramuscular injection of rabies vaccine. But for some inaccessible animals, especially stray dogs, and wild animals, it is difficult to prevent with intramuscular injection. Therefore, it is necessary to develop a safe and effective oral rabies vaccine.Methods:We constructed recombinant Bacillus subtilis (B. subtilis) expressing two different strains of rabies virus G protein, named CotG-E-G and CotG-C-G, immunogenicity was studied in mice.Results:The results showed that CotG-E-G and CotG-C-G could significantly increase the specific SIgA titers in feces, serum IgG titers, and neutralizing antibodies. ELISpot experiments showed that CotG-E-G and CotG-C-G could also induce Th1 and Th2 to mediate the secretion of immune-related IFN-γ and IL-4. Collectively, our results suggested that recombinant B. subtilis CotG-E-G and CotG-C-G have excellent immunogenicity and are expected to be novel oral vaccine candidates for the prevention and control of wild animal rabies.

Therapeutic antibodies-F(ab')2 obtained from hyperimmune equine plasma could treat emerging infectious diseases rapidly because of their high neutralization activity and high output. However, the small-sized F(ab')2 is rapidly eliminated by blood circulation. This study explored PEGylation strategies to maximize the half-life of equine anti-SARS-CoV-2 specific F(ab')2. Equine anti-SARS-CoV-2 specific F(ab')2 were combined with 10 KDa MAL-PEG-MAL in optimum conditions. Specifically, there were two strategies: Fab-PEG and Fab-PEG-Fab, F(ab')2 bind to a PEG or two PEG, respectively. A single ion exchange chromatography step accomplished the purification of the products. Finally, the affinity and neutralizing activity was evaluated by ELISA and pseudovirus neutralization assay, and ELISA detected the pharmacokinetic parameters. The results displayed that equine anti-SARS-CoV-2 specific F(ab')2 has high specificity. Furthermore, PEGylation F(ab')2-Fab-PEG-Fab had a longer half-life than specific F(ab')2. The serum half-life of Fab-PEG-Fab, Fab-PEG, and specific F(ab')2 were 71.41 h, 26.73 h, and 38.32 h, respectively. The half-life of Fab-PEG-Fab was approximately two times as long as the specific F(ab')2. Thus far, PEGylated F(ab')2 has been prepared with high safety, high specificity, and a longer half-life, which could be used as a potential treatment for COVID-19.

以截短的尼帕病毒(NiV)G基因原核表达产物为抗原建立检测尼帕病毒抗体的间接ELISA检测方法.对编码尼帕病毒G蛋白基因的部分序列进行扩增,将扩增获得的 目的片段克隆至原核表达载体pET-30a(+),并转化至大肠杆菌BL21(DE3).菌落PCR鉴定后,在最佳诱导条件下表达目的蛋白.用Ni-NTA柱纯化截短的G蛋白,并进行SDS-PAGE和Western-blot鉴定.以纯化的蛋白为抗原建立尼帕病毒抗体间接ELISA检测方法,并对该方法的特异性、灵敏性、稳定性进行验证.结果显示:成功构建重组质粒pET-30a(+)-NiV-G;表达的尼帕病毒截短G蛋白分子质量为50 ku,与预期值相符;截短的G蛋白能被His-tag抗体、抗尼帕病毒G蛋白粗提IgG识别.以该蛋白为包被抗原建立的间接ELISA检测方法检测已知阳性血清尼帕病毒抗体效价为1∶20480,裂谷热病毒、西尼罗病毒及克里米亚-刚果出血热病毒阳性马血清的检测结果均为阴性,且该方法批内、批间试验变异系数均小于10％.结果表明,成功构建了重组质粒pET-30a(+)-NiV-G,并诱导表达尼帕病毒截短G蛋白.以该蛋白建立的尼帕病毒抗体间接ELISA检测方法具有良好的特异性、灵敏性、稳定性,可用于尼帕病毒疫苗免疫效果的评价、尼帕病毒病的监测及尼帕病毒抗体检测试剂盒的研发.

OBJECTIVE:To investigate the factors affecting phenotypes in the patients of methylmalonic acidemia combined with homocysteinemia cblC type with MMACHC c.609G>A homologous variant. METHODS:A retrospective study on the clinical manifestations, complications, treatment, and outcome in 164 patients of cblC type with MMACHC c.609G>A homologous variant was conducted. The patients were diagnosed by biochemical and genetic analysis from January 1998 to December 2020. RESULTS:Among the 164 patients, 2 cases were prenatally diagnosed and began treatment after birth. They are 3 and 12 years old with normal physical and mental development. Twenty-one cases were diagnosed by newborn screening. Among them, 15 cases had with normal development. They were treated from the age of two weeks at the asymptomatic period. Six cases began treatment aged 1 to 3 months after onset. Their development was delayed. One hundred and forty-one cases were clinically diagnosed. Their onset age ranges from a few minutes after birth to 6 years old. 110 cases had early-onset (78.0%). 31 cases had late-onset (22.0%). Five of them died. 24 patients lost to follow-up. Of the 141 clinically diagnosed patients, 130 (92.2%) with psychomotor retardation, 69 (48.9%) with epilepsy, 39 (27.7%) with anemia, 30 (21.3%) had visual impairment, 27 (19.1%) had hydrocephalus, 26 (18.4%) had feeding difficulties, 7 (5.0%) with liver damage, and 5 (3.5%) with metabolic syndrome. The frequency of hydrocephalus and seizures was significantly higher in the early-onset group. The urinary methylmalonic acid increased significantly in the patients with epilepsy. During the long-term follow-up, the level of plasma total homocysteine in the seizure-uncontrolled group was significantly higher than that in the seizure-controlled group, the difference had a statistical significance (P<0.05). CONCLUSION:Most of the patients with MMACHC c.609G>A homozygous variant had early-onset disease, with a high mortality and disability rate. If not treated in time, it will lead to neurological damage, resulting in epilepsy, mental retardation, hydrocephalus, and multiple organ damage. Pre-symptomatic diagnosis and treatment are crucial to prevent irreversible neurological damage. Neonatal screening and prenatal diagnosis are important to improve the outcome of the patients.

收集经SARS-CoV-2病毒样颗粒(VLPs)为免疫原免疫的健康马血清,采用亲和层析法分离血清中总IgG,利用胃蛋白酶消化Fc片段获得免疫球蛋白F(ab')2,将二者使用结合RBD蛋白的免疫层析柱进行纯化,获得具有高度特异性的马抗SARS-CoV-2IgG与免疫球蛋白F(ab')2.结果显示,特异性IgG与F(ab')2浓度是2.36 mg/mL和1.05 mg/mL,收率为11％和4.89％,纯度在91％与96％以上,对假病毒的半抑制浓度(IC50)为1.406 μg/mL和0.862 μg/mL.结果表明,成功制备了纯度高、特异性强且具有中和活性的马抗SARS-CoV-2特异性IgG与特异性F(ab')2,为制备安全高效的抗SARS-CoV-2治疗性抗体药物奠定了基础.

通过PCR扩增中东呼吸综合征冠状病毒(MERS-CoV)RBD基因片段,将其克隆至真核表达载体pCAGGS中,转染哺乳动物细胞Expi293F,并利用带有StrepTrap标签的亲和柱纯化制备MERS-CoV RBD蛋白,利用SDS-PAGE和Western-blot鉴定纯化后的RBD蛋白.以RBD蛋白为包被抗原,建立骆驼科动物MERS-CoV抗体间接ELISA检测方法.结果显示,MERS-CoV RBD蛋白在Expi293F细胞中以分泌形式表达,纯化后RBD蛋白纯度大于95％;成功建立了骆驼科动物MERS-CoV抗体间接ELISA检测方法.将其初步应用于骆驼、羊驼血清抗体的检测,检测结果与已知血清结果相符合.基于真核表达纯化的高纯度MERS-CoV RBD蛋白,建立了骆驼科动物MERS-CoV抗体间接ELISA检测方法,为骆驼、羊驼等骆驼科动物的MERS-CoV疫苗免疫效果评价、疫病监测等相关研究奠定了基础.

Objective: To analyze the clinical features, genetic characteristics, treatment and follow-up results of patients with hydrocephalus caused by methylmalonic acidemia combined with homocysteinuria, and to discuss the optimal strategies for assessing and treating such patients. Methods: From January 1998 to December 2020, 76 patients with hydrocephalus due to methylmalonic acidemia combined with homocysteinuria in the Department of Pediatrics in 11 hospitals including Peking University First Hospital were diagnosed by biochemical, genetic analysis and brain imaging examination. The patients were divided into operation-group and non-operation-group according to whether they underwent ventriculoperitoneal shunt. The clinical features, laboratory examinations, genotype, and follow-up data were retrospectively analyzed. Data were compared between the two groups using rank sum test, and categorical data were compared using χ2 test. Results: Among the 76 patients (51 male, 25 female), 5 were detected by newborn screening, while 71 were diagnosed after clinical onset, 68 cases (96%) had early-onset, 3 cases (4%) had late-onset. The most common clinical manifestations of 74 cases with complete data were psychomotor retardation in 74 cases (100%), visual impairment in 74 cases (100%), epilepsy in 44 cases (59%), anemia in 31 cases (42%), hypotonia or hypertonia in 21 cases (28%), feeding difficulties in 19 cases (26%) and disturbance of consciousness in 17 cases (23%). Genetic analysis was performed in 76 cases, all of whom had MMACHC gene variations, including 30 homozygous variations of MMACHC c.609G>A. The most common variations were c.609G>A (94, 62.7%), followed by c.658_660del (18, 12.0%), c.567dupT (9, 6.0%) and c.217C>T (8, 5.3%). Therapy including cobalamin intramuscular injection, L-carnitine and betaine were initiated immediately after diagnosis. A ventriculoperitoneal shunt operation was performed in 41 cases (operation group), and 31 patients improved after metabolic intervention (non-operation group). There was no significant difference in the age of onset, the age of diagnosis, the blood total homocysteine, methionine, and urinary methylmalonic acid concentration between the two groups (all P>0.05). The symptoms of psychomotor development, epilepsy, and visual impairments improved gradually after a long-term follow-up in the operation group. Conclusions: Hydrocephalus is a severe complication of methylmalonic acidemia combined with homocysteinuria. The most common clinical manifestations are psychomotor retardation, visual impairment, and epilepsy. It usually occurs in early-onset patients. Early diagnosis and etiological treatment are very important. Hydrocephalus may improve after metabolic intervention in some patients. For patients with severe ventricular dilatation, prompt surgical intervention can improve the prognosis.

Since its first emergence in 2012, cases of infection with Middle East respiratory syndrome coronavirus (MERS-CoV) have continued to occur. At the end of January 2020, 2519 laboratory confirmed cases with a case-fatality rate of 34.3% have been reported. Approximately 84% of human cases have been reported in the tropical region of Saudi Arabia. The emergence of MERS-CoV has highlighted need for a rapid and accurate assay to triage patients with a suspected infection in a timely manner because of the lack of an approved vaccine or an effective treatment for MERS-CoV to prevent and control potential outbreaks. In this study, we present two rapid and visual nucleic acid assays that target the MERS-CoV UpE and N genes as a panel that combines reverse transcription recombinase polymerase amplification with a closed vertical flow visualization strip (RT-RPA-VF). This test panel was designed to improve the diagnostic accuracy through dual-target screening after referencing laboratory testing guidance for MERS-CoV. The limit of detection was 1.2×101 copies/μl viral RNA for the UpE assay and 1.2 copies/μl viral RNA for the N assay, with almost consistent with the sensitivity of the RT-qPCR assays. The two assays exhibited no cross-reactivity with multiple CoVs, including the bat severe acute respiratory syndrome related coronavirus (SARSr-CoV), the bat coronavirus HKU4, and the human coronaviruses 229E, OC43, HKU1 and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Furthermore, the panel does not require sophisticated equipment and provides rapid detection within 30 min. This panel displays good sensitivity and specificity and may be useful to rapidly detect MERS-CoV early during an outbreak and for disease surveillance.

Objective To analyze the clinical characteristics of patients with hydrocephalus secondary to cobalamin C (cblC) deficiency and to discuss the optimal strategies for assessing and treating such patients by performing clinical and laboratory studies in 70 patients. Methods A total of 1,211 patients were clinically diagnosed with methylmalonic acidemia (MMA) from 1998 to 2019. Among them, cblC deficiency was confirmed in 70 patients with hydrocephalus by brain imaging and biochemical and genetic analysis. Results Of the 70 patients, 67 (95.7%) had early-onset MMA and homocystinuria. The patients typically had high blood propionylcarnitine and total homocysteine, low methionine, and methylmalonic aciduria. Signs of intracranial hypertension were relatively rare. We measured ventricular dilatation early in the disease by cranial ultrasound and MRI and/or CT. Eighteen different MMACHC mutations, including 4 novel mutations (c.427C>T, c.568insT, c.599G>A, and c.615C>A), were identified biallelically in all 70 patients. c.609G>A was the most frequent mutation, followed by c.658_660del, c.217C>T, and c.567dupT. Three cases were diagnosed by postmortem study. Metabolic therapy, including cobalamin injections supplemented with oral l-carnitine and betaine, was administered in the remaining 67 cases. A ventriculoperitoneal shunt was performed in 36 cases. During the follow-up, psychomotor development, nystagmus, impaired vision, and sunset eyes improved gradually. Conclusion Hydrocephalus is a severe condition with several different causes. In this study, ventriculomegaly was found in 70 patients with cblC deficiency. Early diagnosis, etiologic treatment, and prompt surgical intervention are crucial to improve the prognosis of patients.

利用PCR技术扩增西尼罗病毒(WNV)E蛋白基因并将其插入原核表达载体pET-30a(+),构建重组质粒pET-30a(+)-WNV-E,并转化至大肠杆菌BL21(DE3)感受态细胞中,经IPTG诱导目的蛋白表达,对诱导条件进行优化,利用His镍柱亲和层析法纯化目的蛋白,纯化后的蛋白经SDS-PAGE与Western-blot鉴定正确后,免疫BALB/c小鼠制备多克隆抗体并进行间接免疫荧光鉴定.结果 显示:WNV E蛋白在大肠杆菌中以包涵体形式被成功表达,蛋白最佳诱导条件为37℃,0.8 mmol/L IPTG诱导5h,经间接免疫荧光鉴定多克隆抗体能特异性识别WNV E蛋白.本研究成功表达并纯化了WNV E蛋白,证明该蛋白具有良好的免疫原性,为WNV抗原、抗体检测方法的建立和新型疫苗的研发及相关研究奠定了基础.

Ebola virus infections lead to severe hemorrhagic fevers in humans and nonhuman primates; and human fatality rates are as high as 67%-90%. Since the Ebola virus was discovered in 1976, the only available treatments have been medical support or the emergency administration of experimental drugs. The absence of licensed vaccines and drugs against the Ebola virus impedes the prevention of viral infection. In this study, we generated recombinant baculoviruses (rBV) expressing the Sudan virus (SUDV) matrix structural protein (VP40) (rBV-VP40-VP40) or the SUDV glycoprotein (GP) (rBV-GP-GP), and SUDV virus-like particles (VLPs) were produced by co-infection of Sf9 cells with rBV-SUDV-VP40 and rBV-SUDV-GP. The expression of SUDV VP40 and GP in SUDV VLPs was demonstrated by IFA and Western blot analysis. Electron microscopy results demonstrated that SUDV VLPs had a filamentous morphology. The immunogenicity of SUDV VLPs produced in insect cells was evaluated by the immunization of mice. The analysis of antibody responses showed that mice vaccinated with SUDV VLPs and the adjuvant Montanide ISA 201 produced SUDV GP-specific IgG antibodies. Sera from SUDV VLP-immunized mice were able to block infection by SUDV GP pseudotyped HIV, indicating that a neutralizing antibody against the SUDV GP protein was produced. Furthermore, the activation of B cells in the group immunized with VLPs mixed with Montanide ISA 201 was significant one week after the primary immunization. Vaccination with the SUDV VLPs markedly increased the frequency of antigen-specific cells secreting type 1 and type 2 cytokines. To study the therapeutic effects of SUDV antibodies, horses were immunized with SUDV VLPs emulsified in Freund's complete adjuvant or Freund's incomplete adjuvant. The results showed that horses could produce SUDV GP-specific antibodies and neutralizing antibodies. These results showed that SUDV VLPs demonstrate excellent immunogenicity and represent a promising approach for vaccine development against SUDV infection. Further, these horse anti-SUDV purified immunoglobulins lay a foundation for SUDV therapeutic drug research.

Feline parvovirus virus (FPV) causes severe diarrhea and leukopenia in felines, and threatening the health of wild and domestic felines. Currently, specific drugs to treat FPV have not yet been developed. In this study, IgG was extracted from inactivated FPV-immunized dog sera. Canine F(ab ')(2) fragments were obtained from pepsin digested IgG and then purified by protein-G column chromatography. The results showed that canine immunoglobulin F(ab ')(2) fragments showed efficient neutralizing activity in vitro against FPV and had therapeutic and prophylactic effects in FPV infected cats. The anti-FPV-specific F(ab ')(2) fragment can significantly alleviate the clinical symptoms of FPV infected cats and reduce the viral loads of the intestinal tract. These results indicated that the F(ab ')(2) fragment prepared from inactivated FPV-immunized felines may be used as a prophylactic and therapeutic agent for diseases caused by FPV.

目的 了解吉林省长春地区犬细小病毒(Canine parvovirus,CPV)的流行及VP2基因的遗传进化特征. 方法 通过比对GenBank中已收录的不同地区、不同时间的CPV毒株基因序列,筛选保守区,设计特异性扩增完整VP2基因的通用型引物,采集疑似犬细小病毒病的犬粪便样品15份,提取DNA,PCR扩增获得完整的VP2基因并测序.将15份样品的测序结果与GenBank中已收录的22株CPV的VP2基因进行同源性比对并构建进化树,分析亚型以及遗传进化情况. 结果 PCR检测15份样品均为CPV阳性.样品株与参考株的核苷酸同源性为98.7％～99.9％,与4株商品化疫苗株的核苷酸同源性在98.1％～98.9％,遗传进化分析显示,15个分离株均为CPV-2c亚型,且所在分支十分接近,但未与所选CPV-2c亚型参考株在同一分支上. 结论 长春地区CPV流行亚型由CPV-2a、CPV-2b逐渐转变为CPV-2c,表明CPV-2c亚型的流行性越来普遍,CPV遗传变异趋势的监测和新型疫苗的研发应得到更多关注.

遗传代谢病是一组以生化代谢异常为特征的单基因遗传病.癫痫发作是遗传代谢病常见的临床表现之一.已知至少5％的癫痫患者是由于遗传代谢病导致.各种各样的小分子代谢病(氨基酸、有机酸、糖、脂肪酸、金属、维生素、神经递质相关代谢障碍)和细胞器代谢病(线粒体、溶酶体、过氧化物酶体)均可表现为癫痫发作或癫痫综合征.遗传代谢病患者临床表现无特异性,生化检测和基因分析是诊断的主要工具.一些代谢性癫痫经过治疗可能减轻症状和改善预后.本文概述了代谢性癫痫的临床特点、辅助检查和治疗.

Methylmalonic acidemia (MMA) is a rare disease which can be prevented and treated.It is the most common organic aciduria in China.MMA has complex genotypes, and its onset varies from the fetal stage to adulthood, which with a high mortality and disability rate.If the treatment is delayed, most patients with MMA would suffer from neuropsychiatric disorders and multiple-organ damage, resulting in epilepsies, psychomotor retardation, anemia, hydrocephalus, cardiomyopathy, pulmonary hypertension, renal insufficiency and visual impairment, and so on.The significant phenotypic and outcomes differences of MMA patients depend on the disease types and the treatment.Newborn screening, prenatal diagnosis and early standardized treatment are the keys to improve the prognosis of the patients.To reduce the mortality and sequelae caused by MMA, multi-disciplinary interventions by neonatologists, critical care experts, geneticists, metabolic specialists, neurologists, cardiologists, nephrologists, pediatric surgeons, obstetricians, medical laboratory physicians, pharmacists, nutritionist and rehabilitation therapists are important.

Background Cobalamin C deficiency ( cblC ) caused by the MMACHC mutations is the most common type of the disorders of intracellular cobalamin metabolism. While the c.609G > A mutation is most frequent in Chinese cblC patients, its correlation with phenotype has not been delineated. Here we aim to investigate the factors affecting variable phenotypes and outcomes associated with the MMACHC c.609G > A homologous mutation in 149 Chinese cases to have implications for treatment and prevention. Methods We assessed 149 cblC patients caused by MMACHC c.609G > A homozygous mutation. The clinical manifestations, complications, treatment, and outcomes were evaluated; 120 patients were followed-up till December 2019. Results Two patients (1.3%) were prenatally diagnosed, treated after birth and consequently showed normal development. In 15 patients (10.1%) detected by newborn screening, 10 were treated at the age of 2 weeks and showed normal development, while the other 5 were treated after onset and showed neurologic disorders. All 132 clinically diagnosed patients (88.6%) developed symptoms at age from few minutes after birth to 72 months. Among them, 101 (76.5%) had early-onset (before the age of 12 months) and 31 (23.5%) had late-onset (after the age of 12 months). Totally 5 patients died and 24 were lost to follow-up. Of the 132 clinical diagnosed patients, 92 (69.7%) presented with developmental delay, 65 (49.2%) had seizures, 37 (28.0%) had anemia, 24 (18.2%) had feeding difficulty, 23 (17.4%) had ocular problems, and 22 (16.7%) had hydrocephalus. Compared with the non-developmental delay group, the onset age, the age at treatment initiation and the time from onset to treatment initiation were later in the developmental delay group. Seizure group showed significantly higher urinary methylmalonic acid concentration. During long-term follow-up, plasma total homocysteine (tHcy) levels were significantly higher in patients in the uncontrolled group than those in the seizure-free group. Conclusions Most cblC patients caused by MMACHC c.609G > A homozygous mutation showed early-onset. The clinically diagnosed patients usually showed the presence of irreversible brain disorders. Patients treated from the pre-symptomatic stage showed favorable outcomes. Therefore, newborn screening, prenatal diagnosis and early treatment are crucial and the c.609G > A mutant allele should be listed in the pre-pregnancy carrier screening panel in China.

Middle East respiratory syndrome coronavirus (MERS-CoV), a new coronavirus that has been causing severe and fatal acute respiratory illnesses in humans since its outbreak in 2012, has raised public fear worldwide. The development of prophylactics and therapeutics is urgently needed to prevent and control MERS-CoV infections. In this study, a bacterium (Lactococcus lactis)-like particle (BLP) vaccine displaying the MERS-CoV receptor-binding domain (RBD) was developed, and gram-positive enhancer matrix (GEM) particles were used as substrates to externally bind to the MERS-CoV RBD through a protein anchor (PA). The designs included different numbers of lysin motif (LysM) repeats in the PAs linked by linkers (RBD-linker-PA2 (RLP2), RBD-linker-PA3 (RLP3) and RBD-PA3 (RP3)), and three LysM repeats and a linker in the fusion proteins increased the binding activity to the RBD. The specific immune responses were tested by intranasally immunizing mice with RLP3-GEM with or without the adjuvant GEL01. The results showed that GEL01-adjuvanted RLP3-GEM increased the systemic humoral, cellular and local mucosal immune responses in the mouse model, especially in the intestinal tract. The above results indicate that the MERS-CoV BLP product has the potential to be developed into a promising mucosal candidate vaccine to protect against MERS-CoV infections.