Twelve-month specific IgG response to SARS-CoV-2 receptor-binding domain among COVID-19 convalescent plasma donors in Wuhan

To investigate the duration of humoral immune response in convalescent coronavirus disease 2019 (COVID-19) patients, we conduct a 12-month longitudinal study through collecting a total of 1,782 plasma samples from 869 convalescent plasma donors in Wuhan, China and test specific antibody responses. The results show that positive rate of IgG antibody against receptor-binding domain of spike protein (RBD-IgG) to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the COVID-19 convalescent plasma donors exceeded 70% for 12 months post diagnosis. The level of RBD-IgG decreases with time, with the titer stabilizing at 64.3% of the initial level by the 9th month. Moreover, male plasma donors produce more RBD-IgG than female, and age of the patients positively correlates with the RBD-IgG titer. A strong positive correlation between RBD-IgG and neutralizing antibody titers is also identified. These results facilitate our understanding of SARS-CoV-2-induced immune memory to promote vaccine and therapy development.

The feasibility of convalescent plasma therapy in severe COVID-19 patients: a pilot study

Currently, there are no approved specific antiviral agents for 2019 novel coronavirus disease (COVID-19). In this study, ten severe patients confirmed by real-time viral RNA test were enrolled prospectively. One dose of 200 mL convalescent plasma (CP) derived from recently recovered donors with the neutralizing antibody titers above 1:640 was transfused to the patients as an addition to maximal supportive care and antiviral agents. The primary endpoint was the safety of CP transfusion. The second endpoints were the improvement of clinical symptoms and laboratory parameters within 3 days after CP transfusion. The median time from onset of illness to CP transfusion was 16.5 days. After CP transfusion, the level of neutralizing antibody increased rapidly up to 1:640 in five cases, while that of the other four cases maintained at a high level (1:640). The clinical symptoms were significantly improved along with increase of oxyhemoglobin saturation within 3 days. Several parameters tended to improve as compared to pre-transfusion, including increased lymphocyte counts (0.65x109/L vs. 0.76x109/L) and decreased C-reactive protein (55.98 mg/L vs. 18.13 mg/L). Radiological examinations showed varying degrees of absorption of lung lesionswithin 7 days. The viral load was undetectable after transfusion in seven patients who had previous viremia. No severe adverse effects were observed. This study showed CP therapy was welltolerated and could potentially improve the clinical outcomes through neutralizing viremia in severe COVID-19 cases. The optimal dose and time point, as well as the clinical benefit of CP therapy, needs further investigation in larger well-controlled trials. Significance StatementCOVID-19 is currently a big threat to global health. However, no specific antiviral agents are available for its treatment. In this work, we explored the feasibility of convalescent plasma (CP) transfusion to rescue severe patients. The results from 10 severe adult cases showed that one dose (200 mL) of CP was welltolerated and could significantly increase or maintain the neutralizing antibodies at a high level, leading to disappearance of viremia in 7 days. Meanwhile, clinical symptoms and paraclinical criteria rapidly improved within 3 days. Radiological examination showed varying degrees of absorption of lung lesions within 7 days. These results indicate that CP can serve as a promising rescue option for severe COVID-19 while the randomized trial is warranted.

Influence of MMP-9 antiseme oligonudeotide on proliferation and apoptosis of human lung adenocarcinom A549 cells / 中国医师杂志

Objective To approach the effects of MMP-9 antisensc oligonucleotide(ASODN)on human lung adcnocarcinoma(A549) cell apoptosis and proliferation capability.Methods MTT.was used to analyze the effect that MMP-9 transfection on A549 cell growth.Flow cytometry was used to analyze the ratio of cell proliferation and apoptosis.RT-PCR WaS used to detect the expression of MMP-9mRNA and Western blot was used to detect the changes of MMP-9 protein.Results In some degree,MMP-9 ASODN that inhibited the survival rate of the A549 cell presented concentration and time dependence manner.The best dependence concentration of ASODN was 600nmol/L for 24 hour.After trasnfection of MMP-9ASODN to A549 cell.the perceive of A549 apoptosis cell was significandy higher than that in control group(P＜0.01).When the antisense oligonucleotides concentration is 600nmol/L and the action time is 48 hours,the relative expression level of MMP-9mRNA and MMP-9 protein are obviously less than that in control group(P＜0.01).Conclusion MMP-9ASODN may down regulate the expression of MMP-9mRNA and MMP-9 protein,effectively inhibit the proliferation of A549 cell and promote the apoptosis of A549 cell.

Relationship between ERCC1 expression and cisplatin intervention in human lung adenocarcinoma cell lines / 中国肺癌杂志

<p><b>BACKGROUND</b>The excision repair cross-complementing gene 1 (ERCC1), which is important in the repair of cisplatin-DNA adducts, is reported to be related to cisplatin resistance in tumor cells. The aim of this study is to investigate the influence of low-dose cisplatin on expression of ERCC1 gene and to confirm the correlation between ERCC1 and cisplatin resistance in human lung adenocarcinoma cell lines.</p><p><b>METHODS</b>A549 and A549/DDP cell lines were treated with 10 μmol/L cisplatin for 12, 24, 48 and 72 h, or treated with 5, 10, 20, 40 μmol/L cisplatin for 24 h respectively. Then the expression of ERCC1 mRNA and protein was measured by RT-PCR and immunocytohistology SABC assay respectively. The resistance of A549/DDP cells was measured by MTT assay.</p><p><b>RESULTS</b>After treating with 10 μmol/L cisplatin for 12 h, up-regulation of ERCC1 mRNA and protein was observed in A549 cells, then reached the peak levels in 72 h group. After treating with 5 μmol/L cisplatin for 24 h, up-regulation of ERCC1 mRNA and protein was observed in A549 cells, and when treated with 20 μmol/L cisplatin for 24 h, the ERCC1 mRNA and protein reached the peak levels. Comparing with the parental cells, ERCC1 expression increased obviously in A549/DDP cells, which were established by continuous low-dose cisplatin treatment.</p><p><b>CONCLUSIONS</b>Up-regulation of ERCC1 expression can be induced by low-dose cisplatin in human lung adenocarcinoma cell line A549, and ECRR1 may play roles in cisplatin resistance.</p>

Study on apoptosis of human lung adenocarcinoma cell line A549/DDP induced by ginsenoside Rh₂ in vitro / 中国肺癌杂志

<p><b>BACKGROUND</b>Lung cancer is one of the leading causes of cancer-related death in mankind. To exploit antitumor drug from plant has been a highlight at home and abroad. The aim of this study is to investigate the apoptosis of human lung adenocarcinoma cell line A549/DDP induced by ginsenoside Rh₂ (G-Rh₂) and to explore its possible molecular mechanism.</p><p><b>METHODS</b>The growth inhibition effect of G-Rh₂ on A549/DDP cells was evaluated by MTT assay. Cell cycle analysis, apoptosis index and tumor related gene expression were detected by flow cytometry. The changes of sApo-1/Fas level in the cell culture supernatant were determined by ELISA method.</p><p><b>RESULTS</b>(1) G-Rh₂ significantly inhibited the growth of A549/DDP cells in a dose-time-de-pendent manner. (2) After 24 hours' treatment with G-Rh₂, apoptosis index of trial group was significantly higher than that of control group (P < 0.001). The proportion of cells in G0/G1 phase in trial group was much higher than that in control group (P < 0.01), while proportion in S phase in trial group was markedly lower than that in control group (P < 0.01). There was no significant difference in proportion in G2/M phase between trial group and control group (P > 0.05). (3) The positive expression rate of p53 and Fas in trial group was significantly higher than that in control group (P < 0.01, P < 0.001), while the positive expression rate of Bcl-2 in trial group was significantly lower than that in control group (P < 0.001). (4) The level of sApo-1/Fas in A549/DDP cell culture supernatant in trial group was remarkably lower than that in control group (P < 0.05).</p><p><b>CONCLUSIONS</b>G-Rh₂ can induce the apoptosis of A549/DDP cells. Its molecular mechanism may be up-regulating expression of p53 and Fas and down-regulating expression of Bcl-2.</p>