Objective To explore the effect and preliminary mechanism of the plant-derived immunostimulatory molecule,ophiopogonin,on enhancing the immune response of a subunit vaccine with the receptor-binding domain(RBD)of coronavirus spike protein as the antigen.Methods CCK-8 assay was used to determine the cytotoxicity of ophiopogonin D'(OPD')on bone marrow-derived dendritic cells(BMDCs).Female Balb/c mice were randomly divided into RBD,RBD/OPD',RBD/Alum,and control groups.The immunization dose was 5 μg of antigen per mouse and 100 μg of adjuvant per mouse,and immunization was carried out according to the intramuscular injection immunization procedure on days 0,21,and 42.The titers of specific IgG and its subtype antibodies were detected by ELISA.The cytokine levels in the supernatant of splenocytes were detected using ELISA.The number of splenocytes secreting IFN-γ was detected by ELISpot.Laser confocal microscopy was employed to observe the uptake of antigen by BMDCs.The phagocytic ability of BMDCs for antigen was quantitatively analyzed by flow cytometry.The mechanism of its enhanced immune effect was preliminarily explored using transcriptomics technology combined with bioinformatics research.Results When the concentration of OPD'was less than 5 μg/mL,the survival rate of BMDCs was 100%.After a single intramuscular injection in mice,except for a slight decrease in body weight,the other biochemical indicators were within corresponding normal ranges.After intramuscular injection immunization of the vaccine,the titers of serum-specific IgG,IgG1,and IgG2a in the RBD/OPD'group were significantly higher than those in the RBD group(P<0.05).Compared with the RBD group,the RBD/OPD'group induced a high-level Th1 cell immune response of IL-1β,TNF-α,and IFN-γ(P<0.01)and had more lymphocytes secreting IFN-γ(P<0.001).Laser confocal microscopy displayed that BMDCs took up more antigens after OPD'treatment,which was further confirmed with flow cytometry in quantitative analysis on antigen uptake rate(P<0.01).Transcriptomics results indicated that there was more significant enrichment of the PPAR signaling pathway in the RBD/OPD'group than the RBD group,suggesting that OPD'may activate the PPAR signaling pathway to exert its adjuvant effect.Conclusion OPD'effectively enhances the immune response of the RBD subunit vaccine,and its action mechanism may be related to the activation of the PPAR signaling pathway.

Objective To establish a mouse model of infection with the minimum lethal dose of Vibrio vulnificus(V.vulnificus)and to evaluate the protective efficacy of inactivated whole-cell(IWC)vaccine using this model.Methods A mouse model of lethal-dose infection was established by intraperitoneal injection of different doses of V.vulnificus.Bacterial colonization in the organs was detected with tissue homogenate plating,and pathological changes in the organs were observed after tissue section staining.Flow cytometry was used to detect immune cell responses after liver tissues were digested into single-cell suspension.IWC vaccine of V.vulnificus was prepared,and the mice were immunized through different routes to observe the protective efficacy of the vaccine.Results A mouse model of infection with the minimum lethal dose at 1×106 CFU of V.vulnificus was successfully established.After infection,the bacteria were mainly colonized in the liver of mice and caused severe pathological damages.Compared with the uninfected mice,the proportion of neutrophils in the liver was significantly increased in the infected mice,whereas the proportions of B cells and T cells were correspondingly decreased(P<0.05).A single intramuscular or intraperitoneal injection of the IWC vaccine could protect the mice effectively against lethal infection of V.vulnificus in 7 d later(P<0.01),although the level of serum IgG having no significant increase.Conclusion A mouse model of lethal-dose infection with V.vulnificus is successfully established,with histopathological characteristics.The IWC vaccine of V.vulnificus rapidly mediates immune protection in this model probably independent of IgG.

Objective:To explore the debridement effectiveness of infected bone tissue of chronic hematogenous osteomyelitis in the lower extremities under the guidance of 99mTc-MDP SPECT/CT fused images. Methods:A retrospective case series analysis was conducted on 21 patients with chronic hematogenous osteomyelitis in the lower extremities treated at Southwest Hospital of Army Medical University from May 2017 to June 2020. There were 8 males and 13 females, with the age range of 10-62 years [23(18, 37)years]. The tibial infections were found in 16 patients, and femoral infections in 5 patients. The duration of bone infection was 4-480 months [120(42, 228)months]. According to the Cierny-Mader anatomico-physiological system, 4 patients were classified as type I, 14 as type III, 3 as type IV; 18 patients were classified as type A and 3 as type B. Intraoperative debridement of infected bone tissue was operated at stage I on the region of interest (ROI) where the isocontour(ISO) value was between 30%-40%, using the preoperative 99mTc-MDP SPECT/CT fused images as the reference. The stage II bone defect reconstruction was based on autologous and / or allogeneic bone. To observe the frequency of operations regarding bone infection control in stage I. The preoperative white blood cell count (WBC), erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), intraoperative bacterial culture and pathological examination were compared at stages I and II. The skin redness and swellings, pain, sinus tract in the infected limbs, and ossification of grafted bones in the original bone defect part were observed at stage II. The accuracy rate between ISO value in the region of interest (ROI) and set ISO figure was checked. The difference of longitudinal length of the bone debridement area in ROI area with the actual bone debridement area was observed under the coronal position. Results:All patients were followed up for 6-36 months [11(9, 29)months] after stage II operation. All of the 21 patients had undergone operations of infection control with an average number of 1.04 times in stage I. 1 patient's intraoperative frozen section indicated that neutrophils were>5/HP. The bone graft at stage II had been completed after another debridement. Comparison of preoperative inflammatory markers at stages I and II: the WBC was decreased from (5.9±1.6)×10 9/L to (5.4±1.5)×10 9/L ( P>0.05), the ESR decreased from 9(5, 26)mm/h to 4(2, 10)mm/h ( P<0.05), and the CRP decreased from 2.8(2.3, 7.7)mg/L to 2.3(1.4, 3.0)mg/L ( P>0.05). The results of bacterial culture of tissue at stage I were positive in 12 patients and negative in 9 patients. The pathological examination indicated neutrophils and lymphocyte infiltration. The results of bacterial culture of tissue at stage II were all negative. A modicum of plasmacyte and lymphocyte infiltration and the neutrophils (<5 per/Hp) had been found in the intraoperative frozen section and pathological examination. No redness, swelling or sinus tract was found in the skin after stage II surgery and ossification of grafted bone was good. The accuracy rate between ISO value in the ROI and set ISO figure was 90.5%. The comparison between longitudinal debridement scope of ROI [(86.8±31.1)mm] and actual bone tissue debridement scope [(86.0±31.3)mm] at stage I showed no significant difference ( P>0.05). Conclusions:99mTc-MDP SPECT/CT fused images can be used as an effective means to define the debridement scope of infected bone tissue preoperatively. The method can not only avoid excessive debridement, but also improve the cure rate of hematogenous osteomyelitis in the lower extremities.

AIM: To investigate the effects of fibroblast growth factor 10 ( FGF10 ) on lipopolysaccharide ( LPS)-induced microglial activation .METHODS:Mouse BV2 microglial cells were maintained in DMEM in a humidified incubator with 95%/5%( V/V) mixture of air and CO 2 at 37℃.The medium was changed every 1 or 2 d.The cells were digested and passaged every 4 or 5 d.The BV2 microglial cells were first pretreated with FGF 10 (1 mg/L) for 30 min and then stimulated with LPS (500 μg/L).The medium and the cells were collected at different time points .The morphologi-cal changes of microglia were visualized under microscope .To evaluate the microglial activation , the transcription and pro-duction of proinflammatory factor tumor necrosis factor-α( TNF-α) were examined by real-time quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA), respectively.RESULTS:The morphology of control BV2 microglia showed circular or oval shape .After exposure to LPS for 24 h, the microglia revealed spindle shaped or multipolar morphology , and the percentage of activated cells was significantly increased compared with control group.Pretreatment with FGF10 successfully inhibited the morphological change from normal to activated shape .LPS sti-mulation for 6 h significantly increased the transcription of TNF-α, while FGF10 pretreatment remarkably reversed the effect.In addition, the production of TNF-αincreased in the presence of LPS stimulation for 24 h compared with control group.Pretreatment with FGF10 suppressed LPS-induced TNF-αexpression.CONCLUSION: Pretreatment with FGF10 inhibits the morphological change from normal to activated shape , and remarkably suppressed the transcription and produc-tion of TNF-α.FGF10 successfully suppresses LPS-induced BV2 microglial activation , indicating that FGF10 is a therapeu-tic agent for the treatment of glia-mediated neuroinflammatory diseases .