Objective:To investigate the mechanism of IL-6 affecting the expression of CD73 on human placenta-derived mesenchymal stem cells (hPMSCs) and regulating their migration, adhesion and proliferation.Methods:Flow cytometry (FCM) and Western blot were used to analyze the effects of exogenous IL-6 or IL-6 secreted by hPMSCs on the expression of CD73 on hPMSCs. The influence of IL-6 on the phosphorylation of signal transducer and activator of transcription 3 (p-STAT3) in hPMSCs was detected by monoclonal antibody blocking test and Western blot. Real-time cellular analysis (RTCA) was used to analyze the changes in the migration, adhesion and proliferation of hPMSCs after knockdown of CD73 expression or APCP pretreatment.Results:FCM and Western blot showed that both exogenous and autocrine IL-6 from hPMSCs promoted the expression of CD73 on hPMSCs ( P<0.001, P<0.01). Moreover, CD73 expression decreased significantly with the presence of IL-6R inhibitor ( P<0.01). IL-6 could up-regulate the levels of both p-STAT3 and CD73 in hPMSCs ( P<0.05, P<0.01), while CD73 expression decreased after adding STAT3 inhibitor ( P<0.01). RTCA showed that knockdown of CD73 expression on hPMSCs significantly inhibited the adhesion and proliferation ability of hPMSCs( P<0.01, P<0.05), but promoted the migration ability of hPMSCs ( P<0.05). Similarly, inhibiting the hydrolase activity of CD73 on hPMSCs by APCP also resulted in a significant decrease in the adhesion and proliferation capacities of hPMSCs, and an increase in the migration capacity of hPMSCs ( P<0.05). Conclusions:IL-6 enhanced the expression of CD73 on hPMSCs via the JAK/STAT3 pathway, thus affecting the migration, adhesion and proliferation of hPMSCs.

Objective:To investigate the role of IL-1β in regulating human placenta-derived mesenchymal stem cells (hPMSCs) to induce the differentiation of activated peripheral blood mononuclear cells (PBMCs) into CD8 + IL-10 + T cell subset in patients with rheumatoid arthritis (RA). Methods:Serum IL-1β levels in RA patients were detected by CBA kit. hPMSCs were isolated from healthy subjects by enzyme digestion. PBMCs that were isolated from RA patients and healthy subjects by Ficoll density gradient centrifugation were activated with PHA and CD3/CD28 monoclonal antibody (McAb) and then co-cultured with hPMSCs. Flow cytometry (FCM) was used to analyze the ability of hPMSCs to induce the differentiation of activated PBMCs into CD8 + IL-10 + T cell subset with the presence of programmed death ligand 1 (PD-L1) and/or PD-L2 McAb and IL-1β. Expression of PD-L1 and PD-L2 on hPMSCs under IL-1β stimulation was analyzed by RT-PCR and FCM. Results:Serum IL-1β levels were significantly higher in RA patients than in healthy subjects. After the activation by PHA and CD3/CD28 McAb, the proportion of CD8 + IL-10 + T cells in PBMCs of RA patients was significantly lower than that of healthy subjects. Moreover, the proportion of CD8 + IL-10 + T cells significantly increased after co-cultured with hPMSCs. The ability of IL-1β-treated hPMSCs to induce activated PBMCs to differentiate into CD8 + IL-10 + T cells was significantly enhanced compared to untreated hPMSCs. IL-1β could up-regulate the expression of PD-L1 and PD-L2 on hPMSCs. Blocking the expression of PD-L1 and/or PD-L2 on hPMSCs significantly reduced the ability of hPMSCs to induce activated PBMCs to differentiate into CD8 + IL-10 + T cells. Conclusions:IL-1β enhanced the capacity of hPMSCs to induce activated PBMCs to differentiate into CD8 + IL-10 + T cells in RA patients by up-regulating the expression of PD-L1 and PD-L2.

Objective: To understand the antigenicity and genetic characterization of influenza B virus HA gene in B/Victoria-lineage virus (BV) in Beijing during 2017-2018. Methods: Thirty BV virus strains isolated from MDCK cell culture by 17 laboratories in Beijing were collected. The antigenicity was analyzed by comparing with the vaccine strain recommended by WHO. The total viral nucleic acid was extracted and HA gene was amplified by RT-PCR and sequenced. The phylogenetic tree was constructed by HA and mutant sites were analyzed. Results: Among 30 strains of BV, 23 strains (76.7%) were low-reactive strains, other 7 strains (23.3%) were related to the vaccine. The phylogenetic analysis showed that the HA gene of all 30 strains located in Clade 1A branch. In addition, amino acid mutations occurred in 8 sites, and 6 of them located in the antigen determining region. Conclusions There was a correlation between the high proportion of low-reactive antigenicity and 6 aa variation in antigenic determinants involved in HA region of BV influenza virus between 2017-2018, which provides an important laboratory basis for the recommendation of BV influenza vaccine.