Objective To investigate the effect of human umbilical cord mesenchymal stem cells (hUC-MSCs) on autophagy and the secretion of chemokine receptor CXCR4 induced by low-dose immunosuppressive durgs.Methods Flow cytometry was used to detect the changes of hUC-MSCs surface markers after treatment with low-dose tacrolimus and rapamycin.The effect of treatment with tacrolimus and rapamycin on proliferation of hUC-MSCs was analyzed with WST-1 assay.Regular RT-PCR was applied to analyze the mRNAs expression of ligands such as LC3B,Atg5 and Beclin1 in hUC-MSCs.Western blotting was carried out to detect the expression of LC3B,Atg5,Beclin1 and p-ULK1 in hUC-MSCs after treatment with tacrolimus and rapamycin.The secretion of chemokine receptor CXCR4 in hUC-MSCs was analyzed under the state of autophay by flow cytometry.Results Flow cytometry analysis confirmed low-dose immunosuppressive drugs tacrolimus and rapamycin did not cause changes in hUC-MSCs phenotypes significantly.Low-dose tacrolimus had no cytotoxic effect on hUC-MSCs,while,rapamycin could inhibit the proliferation of hUC-MSCs after 24 h or 48 h,with survival rate being 73.66％ and 68.81％ (P＜0.05) of controls,respectively.Moreover,both tacrolimus and rapamycin could inhibit PI3K/AKt/mTOR signaling pathway to activate hUC-MSCs autophagy,and the related proteins of LC3B,Atg5 and Beclin1 increased significantly and induced the up-regulation of CXCR4 secretion.Conclusion Our results here demonstrated that low-dose tacrolimus and rapamycin induce autophagy in hUC-MSCs and promote the secretion of CXCR4.

Abstract: In order to search for coumarin-based anti-platelet aggregation compounds with high efficacy and good druggability, twenty-five 3-acetyl-7-hydroxy-coumarin oxime derivatives (6a-6y) were synthesized via Vilsmeier-Haack reaction, Knoevenagel reaction, Williamson reaction, electrophilic substitution reaction and oximation reaction from resorcinol. Their structures were confirmed by HRMS and 1H NMR spectra. The anti-platelet aggregation activity of the target compounds was evaluated using Born’s turbidimetric method. The results revealed that most of them could significantly inhibit platelet aggregation induced by adenosine diphosphate (ADP), collagen, arachidonic acid (AA) and thrombin. Among them, the target compounds 6a and 6b not only had strong inhibitory activity on platelet aggregation induced by the four inducers, but also exhibited good water solubility (3.46 mg/mL and 3.85 mg/mL, respectively) and lipid-water partition coefficient (2.56 and 2.85, respectively) and were expected to become a preclinical candidate compound with multi-target action against platelet aggregation.

Objective To assess the validity of a newly developed in-house ELISPOT IFN-γ release assay (IGRA) for the detection of latent tuberculosis infection among HIV infected individuals. Methods In-house ELISPOT assay were performed, together with a tuberculin skin test in 205 health controls and 110 HIV infected individuals , who had no signs of active tuberculosis at time of enrolment . Results Using the ELISPOT assay, positivity rates for the 205 health controls, 110 HIV infected individuals and 47 AIDS patients on highly active antiretrovial therapy (HAART) were 7. 3% , 24.5% , 29. 8% , respectively. These results indicated that the positive rates obtained from HIV infected individuals (include patient on HAART) was significantly higher than health controls( P ＜ 0.001). We found no significant correlation between the CD4 cell count and positivity of ELISPOT assay (P ＞0.05 ). The proportion of subjects with a positive response to ELISPOT assay were higher than the proportion of tuberculin skin test(TST) responders(P＜0.0001) in HIV infected individuals. Conclusion Our study indicates that IGRA using M. tuberculosis specific antigens are likely to retain their validity for the diagnosis of LTBI among HIV positive individuals.

In order to afford new antiplatelet agents with higher potency, a series of paeonol oxime derivatives (4a-4y) were designed and synthesized from paeonol.Their structures were confirmed by HRMS, 1H NMR spectra.The anti-platelet aggregation activity of the target compounds was evaluated.The results revealed that most of them had moderate to good anti-platelet aggregation activity.Among them, compound 4h and 4j were the most potent on adenosine diphosphate (ADP)-induced platelet aggregation and collagen-induced platelet aggregation. Furthermore, the target compound 4h not only showed strong antiplatelet aggregation activity, but also exhibited good water-solubility and drug-like properties, which can be used as a new antiplatelet active compound for further research.

The ongoing pandemic of Coronavirus disease 19 (COVID-19) is caused by a newly discovered β Coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). How long the adaptive immunity triggered by SARS-CoV-2 can last is of critical clinical relevance in assessing the probability of second infection and efficacy of vaccination. Here we examined, using ELISA, the IgG antibodies in serum specimens collected from 17 COVID-19 patients at 6-7 months after diagnosis and the results were compared to those from cases investigated 2 weeks to 2 months post-infection. All samples were positive for IgGs against the S- and N-proteins of SARS-CoV-2. Notably, 14 samples available at 6-7 months post-infection all showed significant neutralizing activities in a pseudovirus assay, with no difference in blocking the cell-entry of the 614D and 614G variants of SARS-CoV-2. Furthermore, in 10 blood samples from cases at 6-7 months post-infection used for memory T-cell tests, we found that interferon γ-producing CD4
Adaptive Immunity/physiology* ; Adult ; Aged ; Antibodies, Neutralizing/blood* ; COVID-19/immunology* ; Cohort Studies ; Female ; Humans ; Immunoglobulin G/blood* ; Male ; Middle Aged ; SARS-CoV-2/immunology* ; T-Lymphocytes/physiology* ; Time Factors ; Viral Proteins/immunology*