Distinct antibody responses to SARS-CoV-2 in children and adults across the COVID-19 clinical spectrum.

Clinical manifestations of COVID-19 caused by the new coronavirus SARS-CoV-2 are associated with age1,2. Adults develop respiratory symptoms, which can progress to acute respiratory distress syndrome (ARDS) in the most severe form, while children are largely spared from respiratory illness but can develop a life-threatening multisystem inflammatory syndrome (MIS-C)3-5. Here, we show distinct antibody responses in children and adults after SARS-CoV-2 infection. Adult COVID-19 cohorts had anti-spike (S) IgG, IgM and IgA antibodies, as well as anti-nucleocapsid (N) IgG antibody, while children with and without MIS-C had reduced breadth of anti-SARS-CoV-2-specific antibodies, predominantly generating IgG antibodies specific for the S protein but not the N protein. Moreover, children with and without MIS-C had reduced neutralizing activity as compared to both adult COVID-19 cohorts, indicating a reduced protective serological response. These results suggest a distinct infection course and immune response in children independent of whether they develop MIS-C, with implications for developing age-targeted strategies for testing and protecting the population.

Maintenance of the human memory T cell repertoire by subset and tissue site.

BACKGROUND: Immune-mediated protection is mediated by T cells expressing pathogen-specific T cell antigen receptors (TCR) that are maintained at diverse sites of infection as tissue-resident memory T cells (TRM) or that disseminate as circulating effector-memory (TEM), central memory (TCM), or terminal effector (TEMRA) subsets in blood and tissues. The relationship between circulating and tissue resident T cell subsets in humans remains elusive, and is important for promoting site-specific protective immunity. METHODS: We analyzed the TCR repertoire of the major memory CD4+ and CD8+T cell subsets (TEM, TCM, TEMRA, and TRM) isolated from blood and/or lymphoid organs (spleen, lymph nodes, bone marrow) and lungs of nine organ donors, and blood of three living individuals spanning five decades of life. High-throughput sequencing of the variable (V) portion of individual TCR genes for each subset, tissue, and individual were analyzed for clonal diversity, expansion and overlap between lineage, T cell subsets, and anatomic sites. TCR repertoires were further analyzed for TRBV gene usage and CDR3 edit distance. RESULTS: Across blood, lymphoid organs, and lungs, human memory, and effector CD8+T cells exhibit greater clonal expansion and distinct TRBV usage compared to CD4+T cell subsets. Extensive sharing of clones between tissues was observed for CD8+T cells; large clones specific to TEMRA cells were present in all sites, while TEM cells contained clones shared between sites and with TRM. For CD4+T cells, TEM clones exhibited the most sharing between sites, followed by TRM, while TCM clones were diverse with minimal sharing between sites and subsets. Within sites, TRM clones exhibited tissue-specific expansions, and maintained clonal diversity with age, compared to age-associated clonal expansions in circulating memory subsets. Edit distance analysis revealed tissue-specific biases in clonal similarity. CONCLUSIONS: Our results show that the human memory T cell repertoire comprises clones which persist across sites and subsets, along with clones that are more restricted to certain subsets and/or tissue sites. We also provide evidence that the tissue plays a key role in maintaining memory T cells over age, bolstering the rationale for site-specific targeting of memory reservoirs in vaccines and immunotherapies.

Role of autophagy in lipopolysaccharide-induced apoptosis of odontoblasts / 南方医科大学学报

OBJECTIVE@#To investigate the role of autophagy in lipopolysaccharide (LPS)-induced apoptosis of murine odontoblasts.@*METHODS@#Murine odontoblasts (mDPC-23 cells) were treated with 5 μg/mL LPS for 6, 12 and 24 h, and the changes in cell viability was examined using CCK8 kit and cell apoptosis was detected by TUNEL staining. The changes in the protein levels of LC3, Beclin1, Atg5, AKT, p-AKT, mTOR and p-mTOR were detected using Western blotting. The effect of 3-MA treatment for 24 h on LPS-induced apoptosis of mDPC-23 cells was evaluated by detecting the expressions of apoptosis-related proteins caspase-3 and Bax using Western blotting.@*RESULTS@#Stimulation with LPS for 6 and 12 h did not cause significant changes in the proliferation or apoptosis of mDPC-23 cells, but LPS treatment for 24 h significantly suppressed cell proliferation (@*CONCLUSIONS@#LPS stimulation induces autophagy to promote apoptosis of mDPC-23 cells, and suppression of autophagy attenuates LPS-induced apoptosis. Autophagy may play an important role in the injury of inflamed pulp tissues.

Mechanisms of tigecycline resistance in carbapenems-resistant Acinetobacter baumannii strains / 中华微生物学和免疫学杂志

Objective To investigate the mechanisms of tigecycline nonsusceptibility in carbapen-ems-resistant Acinetobacter baumannii ( CRAB) strains in order to provide a theoretical basis for a reasonable use of antibiotics and the control of nosocomial infection .Methods Susceptibility testing of 120 non-dupli-cate CRAB strains to tigecycline was performed by using the broth microdilution method .Minimal inhibitory concentrations ( MIC) of tigecycline against the A.baumannii strains were determined by using the broth mi-crodilution method before and after exposing the strains to Carbonylcyanide-m-chlorophenylhydrazone (CCCP), which was the efflux pump inhibitor .Polymerase chain reaction (PCR) was used to amply the ef-flux pumps genes including adeB, adeJ, adeG, abeM, adeE, adeRS, tetX and tetX1.The real-time PCR was performed to measure the expression of efflux pumps genes including adeB, adeJ, adeG, abeM and adeE.Results A total of 120 CRAB strains were collected including 13 (10.8%) tigecycline non-suscep-tible A.baumannii (TNAB) strains and 107 (89.2%) tigecycline susceptible A.baumannii (TSAB) strains.The MIC values of tigecline to the 120 CRAB strains were in a range of 0.25 μg/ml to 8 μg/ml. The adeR and adeJ genes were detected in 90.0%and 92.5%of the 120 CRAB strains, respectively.The positive rates of adeB, adeS, adeG and abeM genes among the 120 CRAB strains were all 94.2%.None of the three genes including adeE, tetX and tetX1 were detected .The mean expression levels of adeB and adeJ in TNAB strains were respectively increased by 18.69 folds and 5.46 folds as compared with those in sensi-tive strains.No significant increase in the expression of adeG and abeM genes was observed in TNAB strains . A 4-fold decrease in the MIC was observed in 8 out of 13 TNAB isolates treated with 10 μg/ml of CCCP .The CCCP could partially reverse the resistance pattern of tigecycline .Conclusion The efflux pump sys-tems of adeABC and adeIJK rather than the abeFGH and abeM systems might play an important role in reduc-ing the tigecycline susceptibility in carbapenems-resistant A.baumannii strains.

Influence of hypoxia during different pregnancy stages on myocardial remodeling in adult offspring rats / 中华围产医学杂志

Objective To evaluate whether the timing of maternal hypoxia during pregnancy could myocardial remodeling in adult offspring.Methods Twenty-four pregnant rats were assigned to the maternal hypoxia group starting from the early period of pregnancy (G1,day 3 to 21 of pregnancy),the group starting from the middle period of pregnancy (G2,day 9 to 21 of pregnancy),the group starting from the late period of pregnancy (G3,day 15 to 21 of pregnancy),or the control group (G0).Six rats were included in each group.Rats in the maternal hypoxia groups (G1,G2 and G3) were subjected to hypoxia for 3 hours in a low pressure cabin with an oxygen concentration of (10± 1) ％.Systolic blood pressure,wet weight of the left ventricle normalized for body weight (left ventricular weight/body weight,LVW/BW),diameter of cardiomyocytes,and the expression levels of collagen Ⅰ and collagen Ⅲ were measured in adult male offspring at the age of 3 and 5 months.One-way ANOVA and SNK test were used for statistical analysis.Results Maternal hypoxia from day 3 to 21 of pregnancy induced higher systolic blood pressure in male offspring at the age of 3 months and 5 months [3 months:G1 (122.0± 11.7) mmHg,G0 (108.3±9.5) mmHg,F=2.97; 5 months:G1 (128.5±7.9) mmHg,G0 (114.6±-10.0) mmHg,F=3.17,both P＜0.05].Maternal hypoxia also led to a higher LVW/BW ratio (G1 1.99±0.03,G0 1.80±0.02,P＜0.05),and increased collagen Ⅰ and collagen Ⅲ expression (collagen Ⅰ /β-actin:G1 1.76±0.07,G0 0.48±0.04,P＜0.01; collagen Ⅲ /β-actin:G1 0.68±0.05,G0 0.34±0.03,P＜0.01) in adult male offspring at the age of 5 months.Maternal hypoxia from day 9 to 21 of pregnancy induced a higher LVW/BW ratio (3 months:G2 2.15 ± 0.05,G0 1.98 ± 0.02,P＜0.05; 5 months:G2 1.96±±0.05,G0 1.80±0.02,P＜0.05),and increased collagen Ⅰ and collagen Ⅲ expression (3 months:collagen Ⅰ /β-actin G2 0.98±±0.02,G0 0.87±0.02,P＜0.05; collagen Ⅲ /β-actin:G2 0.87±±0.01,G0 0.82±0.01,P＜0.05; 5 months; collagen Ⅰ /β-actin G2 1.61±0.05,G0 0.48±0.04,P＜0.01; collagen Ⅲ / β-actin:G2 0.61 ±0.04,G0 0.34±0.03,P＜0.01) in male offspring at the age of 3 months and 5 months,but did not affect systolic blood pressure.Maternal hypoxia from day 15 to 2l did not have any effect.The diameter of cardiomyocytes in male offspring was not significantly different between the groups.Conclusions Maternal hypoxia during different periods of pregnancy has different effects on cardiac structure in adult rat offspring.Maternal hypoxia started in early or mid-pregnancy leads to cardiac collagen deposition without an increase in myocyte size in adult offspring,which may be independent of the change in blood pressure.

The mechanism of carbapenems resistance in Serratia marcescens strains / 中华微生物学和免疫学杂志

Objective To investigate the mechanism of carbapenems resistance in Serratia marces-cens strains isolated from Wenzhou and their epidemiological characteristics.Methods 147 non-duplicated Serratia marcescens isolates were collected from the First Affiliated Hospital of Wenzhou Medical University during 2006 to 2012.The antimicrobial susceptibility test for all isolates was performed by using Vitek2 Compact to screen carbapenems-resistant Serratia marcescens strains.The minimum inhibitory concentrations ( MICs) of 10 commonly used antibiotics against carbapenems-resistant Serratia marcescens strains were de-termined by agar dilution method.The phenotypes of carbapenemase were analyzed by using the modified Hodge test.PCR analysis was used to detect the genes encoding carbapenemase, AmpC enzyme, efflux pump and outer membrane proteins.The changes of MICs before and after using CCCP efflux pump inhibitor were measured by agar dilution method.Outer membrane proteins were detected by SDS-PAGE.Carbapene-ms resistance genes were transferred from carbapenems-resistant Serratia marcescens strains to recipient strains by conjugation.The transconjugants were amplified by PCR and measured for MICs.Pulsed-field gel electrophoresis ( PFGE) was used to analyze homology among strains.Results 11 isolates resistant to car-bapenems were screened out from 147 Serratia marcescens isolates and all of them were resistant to penicil-lins, cephalosporins and ertapenem.10 out of the 11 isolates were both resistant to imipenem and meropen-em, but remained susceptible to fluoroquinolones and aminoglycoside.Among the 11 isolates, 10 carried blaKPC-2 gene, 1 carried blaIMP-1 gene, 8 harbored both blaEBC and blaMOX genes, 1 harbored both blaEBC and blaDHA genes, and 1 carried blaEBC , blaMOX and blaDHA genes.No additional genes were identified by PCR.The MICs of imipenem to 7 isolates and the MICs of ertapenem to 3 isolates were respectively decreased by 4-64 folds and 8-256 folds after using CCCP.CCCP had no effects on the MICs of meropenem.Loss of outer membrane protein was not detected among the 11 isolates.The blaKPC-2 genes were successfully transferred from 7 isolates into recipient strains.The MICs against the transconjugants were higher than those against the recipient strains in varying degrees.PFGE analysis demonstrated that 8 out of 11 Serratia marcescens strains belonged to one clonotype.Conclusion KPC-2 carbapenemase played an essential role in carbapenems re-sistance in Serratia marcescens strains isolated from Wenzhou.Attention should be paid to the clonal spread of KPC-2 and its horizontal transmission in Wenzhou.

Intervention with flexible bronchoscopy in patiens with respiratory failure caused by tracheal stenosis / 中华急诊医学杂志

Objective To investigate the efficiency and safety of intervention with flexible bronchoscope under general anesthesia by using laryngeal mask in patients with severe tracheal stenosis induced respiratory failure.Methods A total of 16 in-patients with respiratory failure caused by severe tracheal stenosis admitted from September 2009 to March 2012 were retrospectively reviewed.A comprehensive bronchoscopic intervention for the complete patency of airway was successfully performed with various techniques such as cryotherapy,electrocautery,balloon dilatation,and implantation of selfexpanding metal stents under genersl anesthesia by using laryngeal mask.The efficiency of comprehensive bronchoscopic intervention and dyspnea score were evaluated by chest CT scan and bronchoscopic examination before and after the treatment.Data were expressed as ((x-)± s).Paired t test was used for statistical analysis of the data.Results The degrees of tracheal stenosis and dyspnea score before and after intervention were (85.0±8.4)％ vs.(20.9±7.6)％ (P＜0.01) and (3.9±0.3vs.2.4±0.5,P＜ 0.01),respectively.There were no life-threatening complications occurred including massive haemorrhage.Conclusions It is an effective and safe technique to resolve the tracheal stenosis-induced respiratory failure with intervention by using flexible bronchoscope under general anesthesia with laryngeal mask,and it is a promising interventional treatment for clinic application.

Relationship between heart diastolic function and pulse wave velocity in patients with diabetes mellitus / 中国综合临床

Objective To evaluate the relationship between the heart diastolic function and pulse wave velocity in patients with diabetes mellitus.Methods Fifty-five patients with diabetes mellitus underwent echocardiogram exam,PWV,and BNP determination.Patients were divided into two groups according to the results:the group with normal heart diastolic function(n =33)and the group with abnormal heart diastolic function( n =22).Another 30 healthy volunteers served as control group.The values of PWV were compared.between the three groups.The relationship between E/E' and PWV,BNP and PWV were evaluated with correlation analysis.Results The PWV value of abnormal heart diastolic function group was significantly higher than that of other two groups.PWV was positively correlated with E/E'and BNP ( r =0.58,P ＜ 0.05 ; r =0.63,P ＜ 0.05).Conclusion PWV is associated with the heart diastolic function.PWV can serve as an important factor to predict abnormal heart diastolic function in patients with diabetes mellitus.

The change and clinical significance of electromyogram in type 2 diabetic patients / 中国实用内科杂志

Objective To study the clinical ralue of electromyogram in te sting peripheral nerves in diabetic patients and study the factors affecting per ipheral nearopathy. Methods FBG, 2HBG, HbA1c and electromyogram of nerves peronaeus communis and superficialis were measured in 2 3 diabetic patients. Result The result of electromyogram accord ed with clinical symptoms. Diabetic patients with neurological symptoms had higher voltage, prolo nged time limit of light contract peak value, and increased multiphase electric p otential compared with those without neurological symptoms (p

Antibody responses to SARS-CoV2 are distinct in children with MIS-C compared to adults with COVID-19

Clinical manifestations of COVID-19 caused by the novel coronavirus SARS-CoV-2 are associated with age. While children are largely spared from severe respiratory disease, they can present with a SARS-CoV-2-associated multisystem inflammatory syndrome (MIS-C) similar to Kawasakis disease. Here, we show distinct antibody (Ab) responses in children with MIS-C compared to adults with severe COVID-19 causing acute respiratory distress syndrome (ARDS), and those who recovered from mild disease. There was a reduced breadth and specificity of anti-SARS-CoV-2-specific antibodies in MIS-C patients compared to the COVID patient groups; MIS-C predominantly generated IgG Abs specific for the Spike (S) protein but not for the nucleocapsid (N) protein, while the COVID-19 cohorts had anti-S IgG, IgM and IgA Abs, as well as anti-N IgG Abs. Moreover, MIS-C patients had reduced neutralizing activity compared to both COVID-19 cohorts, indicating a reduced protective serological response. These results suggest a distinct infection course and immune response in children and adults who develop severe disease, with implications for optimizing treatments based on symptom and age.