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The emergence of coronavirus disease 2019 (COVID-19) pandemic led to an urgent need to develop therapeutic interventions. Among them, neutralizing antibodies play crucial roles for preventing viral infections and contribute to resolution of infection. Here, we describe the generation of antibody libraries from 17 different COVID-19 recovered patients and screening of neutralizing antibodies to SARS-CoV-2. After 3 rounds of panning, 456 positive phage clones were obtained with high affinity to RBD (receptor binding domain). Then the positive clones were sequenced and reconstituted into whole human IgG for epitope binning assays. After that, all 19 IgG were classified into 6 different epitope groups or Bins. Although all these antibodies were shown to have ability to bind RBD, the antibodies in Bin2 have more superiority to inhibit the interaction between spike protein and angiotensin converting enzyme 2 receptor (ACE2). Most importantly, the antibodies from Bin2 can also strongly bind with mutant RBDs (W463R, R408I, N354D, V367F and N354D/D364Y) derived from SARS-CoV-2 strain with increased infectivity, suggesting the great potential of these antibodies in preventing infection of SARS-CoV-2 and its mutations. Furthermore, these neutralizing antibodies strongly restrict the binding of RBD to hACE2 overexpressed 293T cells. Consistently, these antibodies effectively neutralized pseudovirus entry into hACE2 overexpressed 293T cells. In Vero-E6 cells, these antibodies can even block the entry of live SARS-CoV-2 into cells at only 12.5 nM. These results suggest that these neutralizing human antibodies from the patient-derived antibody libraries have the potential to become therapeutic agents against SARS-CoV-2 and its mutants in this global pandemic.
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BACKGROUND:Different local anesthetic solutions for tumescent liposuction are necessary and have a certain effect on the biological characteristics of human adipose stem cels. OBJECTIVE:To explore the effect of different tumescent local anesthesia on the proliferation and differentiation of human adipose stem cels culturedin vitro. METHODS: Passage 3 human adipose stem cels were intervened by different tumescent local anesthesia (bupivacaine, ropivacaine, lidocaine). Cels cultured in low-glucose DMEM served as controls. Proliferation ability, lactate dehydrogenase activity in the supernatant and percentage of cels under adipogenic differentiation were detected. RESULTS AND CONCLUSION:After intervention for 1, 2, 3, 4, 5 days, the supernatant lactate dehydrogenase activity in the bupivacaine, ropivacaine, lidocaine groups was significantly higher than that in the control group (P 0.05). Overal, these findings indicate that different tumescent local anesthesia (bupivacaine, ropivacaine, lidocaine) can al inhibit the proliferation of human adipose stem cels, but have no certain effects on the adipogenic differentiation.
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Objective To evaluate the role of p38 mitogen-activated protein kinase (p38MAPK)-heat shock protein 27 (HSP27) signaling pathway in attenuation of lipopolysaccharide (LPS)-induced acute lung injury (ALl) by dexmedetomidine in mice.Methods Forty male Kunming mice,aged 2 months,weighing 20-25 g,were equally and randomly divided into 4 groups using a random number table:control group (group C),LPS group,low-dose dexmedetomidine + LPS group (group D1),and high-dose dexmedetomidine + LPS group (group D2).Dexmedetomidine 25 and 50 μg/kg were injected intraperitoneally in D1and D2 groups,respectively,and 1 h later LPS 5 mg/kg was injected intraperitoneally.At 6 h after LPS injection,the left lung was lavaged,and broncho-alveolar lavage fluid (BALF) was collected for determination of concentrations of protein,tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β).The right lung was removed for examination of the pathological changes (under the light microscope) and for detection of expression of phosphorylation of p38MAPK (p-p38MAPK),p38MAPK,phosphorylation of MAPK-activated protein kinase 2 (p-MAPKAPK-2),MAPKAPK-2,phosphorylation of HSP27 (p-HSP27) and HSP27 in lung tissues.The wet to dry lung weight (W/D) ratio was calculated.The ratios of p-p38MAPK/p38MAPK,p-MAPKAPK-2/MAPKAPK-2 and p-HSP27/HSP27 were calculated.Results Compared with group C,the W/D ratio,concentrations of protein,TNF-α and IL-1β in the BALF,and ratios of p-p38MAPK/p38MAPK,p-MAPKAPK-2/MAPKAPK-2 and p-HSP27/HSP27 were significantly increased in group LPS.Compared with group LPS,the W/D ratio,concentrations of protein,TNF-α and IL-1β in the BALF,and ratios of p-p38MAPK/p38MAPK,p-MAPKAPK-2/MAPKAPK-2 and p-HSP27/ HSP27 were significantly decreased in D1 and D2groups.The pathological changes of the lung were significantly reduced in D1 and D2 groups as compared to LPS group.Conclusion Dexmedetomidine attenuates LPS-induced ALI in mice possibly through inhibiting p38MAPK-HSP27 signaling pathway.
