Objective:To obtain a high specificity and high affinity anti-human PD-L1 monoclonal antibody which can be used for clinical diagnosis and block PD-L1 and PD-1 binding.Methods:BALB/c mice were immunized with recombinant PD-L1 protein.The positive cell clones stably secreting anti-human PD-L1 monoclonal antibody were obtained by classical hybridoma cell fusion technique.The specificity,affinity,subtype and other characteristics of the antibody were identified by ELISA.Immunofluorescence and indirect immunofluorescence were used to detect the tumor cells.Antibody blocking activity was confirmed by tumor killing test.Results:Two cell strains stably secreting monoclonal antibodies against human PD-LI were screened out.Abl and Ab2 had high titer and affinity.The antibody titers were 1:2.56×106 and 1:3×105,and the affinity was 1.5×109 L/mol and 2.5×10s L/mol respectively.There was no cross reaction between these two antibodies and PD-L2.Immunoblotting,indirect immunofluorescence confirmed that the antibody can be used to the diagnosis.Experiment showed that PD-L1 antibodies can increases tumor-killing activity of CIK cells.Conclusion:Two hybridoma cell lines capable of stably secreting highly specific and high affinity anti-human PD-L1 monoclonal antibody are obtained.They can specifically bind to PD-L1 molecules on tumor cells and can be used to the diagnosis of tumor phenotype and prognosis.Antibody blocking function can be applied to combined CIK cell immunotherapy.

BACKGROUND:Vertebroplasty and kyphoplasty can effectively repair osteoporotic vertebral compression fractures, but bone cement injection can cause the change of stress in the fractured vertebrae and adjacent vertebrae after surgery, leading to new fractures.
OBJECTIVE: To analyze the stress changes of the fractured vertebrae and adjacent vertebrae after vertebroplasty with different elastic modulus bone cement by a three-dimensional finite element method.
METHODS: One healthy adult male volunteer was selected for lumbar spine CT scan. The acquired images were imported for three-dimensional reconstruction using Mimics. The three-dimensional model was smoothed, polished and denoised by Geomagic software, and then the solid mode was built under Workbench Ansys. An osteoporotic vertebral compression fracture model in L2-4 segments was established after assignment. Bone cement (4 mL) with different elastic moduli (8 000, 4 000, 2 000 and 1 000 MPa) injected into the L3 segment distributed in the middle of the vertebrae as spherical shape. 500 N pre-load was applied on the L2 surface with an additional bending moment of 50 N?m. The lower surface free degree of L4 was restrained. The L2-4 forward flexion, posterior extension, right flexion and axial rotation on the right side were stimulated. The stress changes of the fractured vertebrae and the upper and lower adjacent vertebrae before and after bone cement injection with different elastic moduli were compared.
RESULTS AND CONCLUSION:The stress of the fractured vertebrae and adjacent vertebrae were significantly increased compared with that before operation. With the increase of elastic modulus, the stress of the fractured vertebrae increased, but there were no changes in the stress of adjacent vertebrae. These findings indicate that the elastic modulus of bone cement may be a method to reduce new fractures of the fractured and adjacent vertebrae after bone cement injection.

BACKGROUND:Vertebroplasty and kyphoplasty can effectively repair osteoporotic vertebral compression fractures, but postoperative change of stress in the fractured vertebrae and adjacent vertebrae can lead to new fractures. OBJECTIVE:To analyze the stress changes of the fractured and adjacent vertebrae with different bone cement injection volume by three-dimensional finite element method. METHODS:One healthy adult male volunteer was selected for lumbar spine CT scan. The acquired images were imported for three-dimensional reconstruction using Mimics. The three-dimensional model was smoothed, polished and denoised by Geomagic software, and then the solid mode was built under Workbench Ansys. The osteoporotic vertebral compression fracture model in L2-L4 segments was established after assignment. Bone cement of 1, 2, 4, 6 mL was injected into the L3 vertebrae respectively and distributed in the middle of the vertebrae as spherical shape. 500 N pre-load was applied on L2 surface with an additional moment of 50 N·m. The lower surface free degree of L4 was restrainted. The L2-L4 forward flexion, extension, right flexion and axial rotation on the right side were stimulated to compare the stress changes of fractured vertebrae and adjacent vertebrae before and after the bone cement injection with different volume. RESULTS AND CONCLUSION:The stresses of fractured and adjacent vertebrae after the bone cement injection were significantly increased; meanwhile, the stresses of fractured and adjacent vertebrae increased with the increase of bone cement injection volume, which may be one of the factors leading to the compression fractures of adjacent vertebrae.

Objective:To investigate the reparative efficacy and mechanism of pressure-adjustable macroporous antibacterial hydrogel in the treatment of infected wounds.Methods:Staphylococcus aureus was used to establish wound infection models in healthy C57BL/6 mice. The models were divided into 3 groups subjected to 3 different treatments: a negative control group with no hydrogel treatment (group A), a control group treated by common medical hydrogel (group B) and an experiment group treated by pressure-adjustable macroporous antibacterial hydrogel (group C). On days 1, 3, 6, 9 and 12, the effects of 3 treatments were compared on the wound area and the number of bacterial colonies under scab, on the apoptosis of fibroblasts based on the changes of type Ⅰ procollagen, and on the inhibition of inflammation during wound repair by detecting the expression of interleukin-6 (IL-6) and tumor necrosis factor (TNF-α).Results:On days 1 and 3, there was no significant difference between the 3 groups in the wound area ( P>0.05), but on days 6, 9 and 12, there were significant differences between the 3 groups in the wound area ( P<0.05). On day 6, the wound areas in group B (1.23 cm 2 ± 0.16 cm 2) and in group C (1.14 cm 2 ± 0.12 cm 2) were significantly smaller than that in group A (1.56 cm 2 ± 0.16 cm 2) ( P<0.05), but there was no significant difference between groups B and C ( P>0.05). On days 9 and 12, the wound areas in group B (0.97 cm 2 ± 0.13 cm 2 and 0.76 cm 2 ± 0.10 cm 2) and in group C (0.66 cm 2 ± 0.06 cm 2 and 0.48 cm 2 ± 0.07 cm 2) were significantly smaller than those in group A (1.49 cm 2 ± 0.11 cm 2 and 1.39 cm 2 ± 0.13 cm 2), and those in group C were significantly smaller than those in group B (all P<0.05). On day 1, there was no significant difference between the 3 groups in the number of bacterial colonies under scab ( P>0.05). On days 3, 6, 9 and 12, the numbers of bacterial colonies under scab in groups B and C were significantly smaller than that in group A ( P<0.05), and that in group C was significantly smaller than that in group B ( P< 0.05). The nucleic acid electrophoresis showed that the grayscale bands in group C were significantly darker than those in groups A and B. The early apoptosis rate of the fibroblasts in group C[low-right positive fluorescence (LR%): 9.72%] was significantly lower than that in group A (43.99%) and that in group B (38.43%), and that in group B was significantly lower than that in group A ( P<0.05). On day 12, the ratio of the gray values of IL-6 and β-actin (0.64 ± 0.10) and the ratio of the gray values of TNF-α and β-actin (0.34 ± 0.05) in the fibroblasts in group C were significantly higher than those in group A (1.22 ± 0.21 and 0.60 ± 0.14) and in group B (0.88 ± 0.02 and 0.41 ± 0.06) ( P<0.01). Conclusion:The pressure-adjustable macroporous antibacterial hydrogel is an effective treatment of infected wounds and its mechanism may be related to the reduced apoptosis of fibroblasts.