[Study of local application of CpG-oligodeoxynucleotide combined with 4-1BB monoclonal antibody to treat hepatoma- bearing mice].

Objective: To investigate the curative effect of local application of CpG-oligodeoxynucleotide (CpG-ODN) combined with 4-1BB monoclonal antibody in hepatoma-bearing mice, and to evaluate the effect of 4-1BB monoclonal antibody on CpG-ODN immunotherapy. Methods: H22 single cell suspension was injected subcutaneously into the axilla and four limbs of the BALB/c male mice to establish a tumor-bearing mice model. After 7 days, 30 mice with corresponding tumor-bearing volume were screened and randomly divided into model control group, CpG group and CpG+4-1BB group, and the drug was injected into the tumors of left lower extremity. The same batch of normal mice was selected as normal control group. Survival of mice was recorded. Tumor-bearing volume and organ index were calculated. Serum levels of interleukin (IL) - 12 and interferon (IFN) gamma and spleen CD8(+)T lymphocyte ratio were measured. The measurement data were analyzed by analysis of variance. The survival rate of each group of mice was analyzed by log-rank test. Results: Mice in the model control group with tumor-bearing volume had a sustained growth before the execution. CpG group and the CpG+4-1BB group [(976.08 ± 29.55) mm(3), (47.25 ± 0.93) mm(3))] tumor-bearing volume was decreased than model group [(1 336.52 ± 39.40) mm3] (F = 5 329.273, P < 0.05). CpG+4-1BB group distant tumor-bearing volume [(611.83 ± 113.02) mm3] was decreased than model group and CpG group [(1 406.62 ± 51.09) mm(3), (1 380.01 ± 51.44) mm3] (F = 247.160, P < 0.05), but there was no significant difference between the CpG group and the model group (P > 0.05). Serum IL-12 concentration (23.90 ± 2.33 pg/ml), IFN-γ concentration (103.02 ± 6.10 pg/ml) and spleen CD8(+)T cell ratio (4.54 ± 0.62%) in the model group were lower than those in the normal group (P < 0.05). Serum IL-12 concentration in CpG group and CpG+4-1BB group (29.21 ± 2.23 pg/ml, 37.04 ± 1.49 pg/ml), IFN-γ concentration (116.12 ± 4.08 pg/ml, 138.65 ± 1.72 pg/ml), CD8(+)T cell ratio (6.65 ± 0.64%, 12.73 ± 0.88%) were higher than the model group, while CpG+4-1BB group was higher than the CpG group (P < 0.05). The survival rate of CpG+4-1BB group was higher than that of model group and CpG group (χ(2) = 25.544, P < 0.05), but there was no significant difference between CpG group and model group (P > 0.05). There was no significant difference in organ index between the four groups (P > 0.05). Conclusion: 4-1BB monoclonal antibody combined with CpG-ODN therapy can shrink hepatoma-bearing capacity, inhibit the growth of distant tumors and significantly prolong the survival time of mice.

[Establishment of a cell co-culture system in accordance with the immunological characteristics of chronic HBV infection].

Objective: To investigate whether the co-culture of Huh7.93 cells and peripheral blood mononucleated cells from chronic hepatitis B patients (cPBMCs) can simulate the replication features of hepatitis B virus (HBV) and immune function in chronic hepatitis B (CHB) patients, and to provide an in vitro cell co-culture system for the research on immune clearance in chronic HBV infection. Methods: Huh7.93 cells were cultured alone or co-cultured with peripheral blood mononucleated cells from healthy people who underwent physical examination (nPBMCs) or cPBMCs for 7 days. The CCK8 assay was performed to measure the proliferative activity of Huh7.93 cells, and quantitative real-time PCR and Southern blot were used to measure HBV replication in cPBMCs and co-cultured cells. The independent samples t-test was used for comparison between two groups. Results: When Huh7.93 cells were co-cultured with peripheral blood mononucleated cells (PBMCs) at a certain ratio, Huh7.93 cells had a high proliferative activity and good cell growth. HBV could not infect or replicate in cPBMCs. HBV DNA in the supernatant of Huh7.93 cells co-cultured with cPBMCs showed significant increases and significantly higher than that in the supernatant of Huh7.93 cells cultured alone on day 4 (6.01 ± 0.20 log10copies/ml vs 4.99 ± 0.08 log10copies/ml, P = 0.000) and day 7 (7.82 ± 0.24 log10copies/ml vs 6.96±0.09 log10copies/ml, P = 0.000). On day 7 of culture, the cell lysis buffer of Huh7.93 cells co-cultured with cPBMCs had a significant increase in the level of HBV replicative intermediate compared with that of Huh7.93 cells cultured alone. After HepG2.2.15 cells were co-cultured with cPBMCs, there was no significant increase in HBV replication. Conclusion: The co-culture of Huh7.93 cells and cPBMCs produces similar viral replication as human body infected with HBV and can well simulate the liver microenvironment and immune function in CHB patients, which provides a new method for the research on immune clearance in chronic HBV infection.