Objective To investigate the immunomodulatory effects of heme oxygenase-1 ( HO-1) modified rat bone marrow mesenchymal stem cells ( BM-MSCs) on lymphocytes .Methods Rat BM-MSCs were cultured and identified in vitro.HO-1 gene was transduced into BM-MSCs via recombinant adenovirus (rAdV) to construct HO-1/BM MSCs, which were then co-cultured with rat spleen lymphocytes .The cellu-lar activity of lymphocytes was detected by using MTT method .The cell cycle distributions were analyzed by propidium iodide staining and flow cytometry .ELISA was used to detect the level of cytokines in the super-natant of cultured cells .The expression of lymphocyte activation markers , CD25 and CD71, were measured by using fluorescence labeled antibodies and flow cytometry .Results Compared with the control group , the lymphocytes co-cultured with HO-1/BM MSCs showed a suppressed proliferation and cell cycle progression . HO-1/BM MSCs inhibited the secretion of IL-2, TNF-αand IFN-γ, but enhanced the secretion of IL-10 in lymphocytes.Furthermore, the expression of CD25 and CD71 were also down-regulated by HO-1/BM MSCs. Conclusion Compared with BM MSCs , HO-1/BM MSCs show higher immunosuppressive effects on lym-phocytes .

Objective To establish method of constructing lentiviral vectors to express microRNA (miRNA) ''tough decoy''(TuD)and to detect the effects of the TuD on cellular endogenous miRNA level and cellular phenotypes. Methods Two-step cloning strategy was utilized to first generate a universal miRNA TuD frame vector,followed by con-structing the TuD expression vector specially targeting miR-203. The package of the recombinant lentivirus was per-formed in 293T cells. Then the rat bone marrow mesenchymal stem cells(BM-MSCs)were infected by the miR-203 TuD expression lentivirus. The pSIH1-H1-copGFP vector was also packaged and the BM-MSCs infected by this lentivirus were served as control. Endogenous miR-203 level in BM-MSCs was measured by quantitative RT-PCR,and cellular vi-ability and apoptosis were detected by CCK-8 test and Annexin V-PI staining respectively. Results The miR-203 TuD expression vector was successfully constructed and inserted sequence was validated. At the 3rd,6th and 9th days after in-fected by the miR-203 TuD expression lentivirus,rat BM-MSCs exhibited a repressed endogenous miR-203 level. The miR-203 TuD also promoted viability and inhibited apoptosis of BM-MSCs. All these differences between miR-203 TuD group and control group were statistically significant. Conclusion The two-step cloning method for the construction of miRNA TuD expression vector is simple and efficient. The miRNA TuD can effectively suppress the level of the target miRNA and affect cellular phenotypes.

Objective:To compare the changes of clinical characteristics and immune-related indicators of patients with mild and moderate acute Omicron variant infection, and to evaluate the protective effect of coronavirus disease 2019 (COVID-19) vaccination.Methods:The study retrospectively analyzed the clinical characteristics of 317 adult patients diagnosed with COVID-19 Omicron variant (B1.1.529) infection admitted to Tianjin First Central Hospital (Shuixi District) from January 22, 2022 to February 24, 2022. Demographic characteristics, vaccination status, underlying diseases, epidemiological characteristics, baseline data, and relevant laboratory test results on admission were collected, and the differences in clinical characteristics, especially the changes in immune-related indicators, between mild and moderate patients were compared and analyzed.Results:Among the 317 adult patients with acute Omicron variant infection, the proportion of elderly, hypertension, diabetes, and cardiovascular or cerebrovascular diseases were significantly higher in moderate group (203 cases) than those of mild group (114 cases) [age≥60 years old: 27.58% (56/203) vs. 9.65% (11/114), hypertension: 31.03% (63/203) vs. 19.30% (22/114), diabetes: 15.76% (32/203) vs. 7.89% (9/114), cardiovascular and cerebrovascular diseases: 11.33% (23/203) vs 0.88% (1/114), all P < 0.05]. The route of transmission was mainly through gatherings and the first symptoms were fever, dry cough, fatigue, sore throat, nasal congestion, runny nose and other flu symptoms; 19.30% (22/114) and 24.63% (50/203) of patients in mild and moderate groups were positive for the new coronavirus nucleic acid test, respectively, but the difference was not significant difference ( P > 0.05). Inflammatory indicators in most mild and moderate patients were within normal range, such as white blood cell count (WBC), neutrophil ratio (NEU%), lymphocyte count (LYM), C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6), etc., suggesting that the acute phase of Omicron variant infection had not yet caused severe inflammatory storm, which might be related to the weakening of pathogenicity after vaccination and virus mutation. The proportion of patients with IL-6 > 7 ng/L in the mild group was significantly lower than that in the normal group [1.75% (2/114) vs. 6.40% (13/203), P < 0.05], suggesting that elevated IL-6 might be an important factor in evaluating indicators of disease severity. There was no significant difference in lymphocyte subsets between the two groups, but there were 12.90% (12/93) and 11.04% (17/154) of the patients in two groups, respectively, decreased in the proportion of helper T cells, and 18.28% (17/93) and 14.28% (22/154) of the patients had elevated CD4 +/CD8 + ratio, suggesting that patients with Omicron variant infection had autoimmune system dysfunction, which might be related to disease progression and the occurrence of long-term autoimmune disease. Conclusions:Serum IL-6 level may be used as a predictor for evaluating the severity of disease in patients with Omicron variant infection; after vaccination, inflammatory indicators in patients with acute Omicron variant infection were significantly reduced, but the long-term effects still require long-term follow-up observation.