OBJECTIVETo test the antitumor effect of a human triple-negative breast cancer cell-dendritic cell (DC) fusion vaccine.

METHODSDCs were isolated from fresh peripheral blood of healthy donors. The fusion vaccine was prepared by fusing the DCs and MDA-MB-231 cells via electrofusion. The morphology of the vaccine was identified under inverted fluorescence microscope and the phenotypes were analyzed with flow cytometry. The production of interleukin-12 (IL-12) and interferon-γ (IFN-γ) by the fusion cells was assessed using ELISA. A CCK-8 kit was used to examine the effect of the vaccine in stimulating the proliferation and cytotoxicity of autologous T lymphocytes.

RESULTSThe DCs isolated from peripheral blood mononuclear cells highly expressed CD83, CD86, CD11c and HLA-DR on the cell surface. The fusion cells were irregular in shape and coexpressed the phenotypes of DCs and MDA-MB-231 cells. The fusion cells possessed a strong ability to stimulate the proliferation of T lymphocytes in vitro. Compared with the control group, the fusion vaccine showed a stronger antitumor effect against the breast cancer cells.

CONCLUSIONThe triple-negative breast cancer-DC fusion vaccine prepared by electrofusion can stimulate the proliferation of T lymphocytes and induces strong cytotoxicity of the T cells against breast cancer cells.

Breast Neoplasms ; immunology ; Cancer Vaccines ; immunology ; Cell Fusion ; Cell Line, Tumor ; Dendritic Cells ; immunology ; Female ; Humans ; Interferon-gamma ; immunology ; Interleukin-12 ; immunology ; Lymphocyte Activation ; T-Lymphocytes, Cytotoxic ; immunology

Objective To investigate the role of SIAH2 protein in the occurrence and development of hepatocellular carcinoma (HCC). Methods Human HCC Bel-7404 cells in logarithmic growth phase were inoculated. Empty carrier small interference ribonucleic acid (siRNA) and SIAH2 siRNA were transfected in human HCC Bel-7404 cells. Then the cells were divided into 2 groups:control-siRNA group and SIAH2-siRNA group. Theβ-actin was taken as control, and the expression of SIAH2 protein in human HCC Bel-7404 cells of 2 groups was detected by Western Blot. The proliferation of cells in 2 groups was detected by methyl thiazolyl tetrazolium (MTT) assay. Cell migration in 2 groups was observed by cell scratch test. Cell invasion in 2 groups was observed by Transwell assay. The data in 2 groups were compared using t test. Results The average relative expression of SIAN2 in control-siRNA and SIAH2-siRNA group were 0.71±0.02, 0.33±0.01 respectively. The expression of SIAN2 in SIAH2-siRNA group decreased obviously compared with that in control-siRNA group (t=-4.629, P<0.05). The proliferation rate in SIAH2-siRNA group also decreased obviously. The cell migration rate in SIAH2-siRNA group[(14.3±0.4)%] was significantly lower than that in control-siRNA group [(45.3±0.4)%]( t=-3.689, P<0.05). The membrane permeating cell count in SIAH2-siRNA group (122±7) was signiifcantly less than that in control-siRNA group (563±10) (t=-3.428, P<0.05). Conclusion SIAH2 protein can promote the proliferation, migration and invasion of HCC cells and thus accelerate the occurrence and development of HCC.

Objective To establish a NOD/SCID mouse model with human immune reconstitution and observe its immune response to human triple-negative breast cancer xenograft. Methods Twenty-four NOD/SCID mice without immune leakage were subjected to cyclophosphamide (CTX) treatment 3 days prior to immune reconstitution with human peripheral blood mononuclear cell (PBMC) injection and subcutaneous transplantation of human triple-negative breast cancer MDA-MB-231 cells, CTX treatment and PBMC injection without tumor cell transplantation, MDA-MB-231 cell transplantation only, or no treatments. The tumor growth and immune responses of the mice were observed at regular intervals. Results Compared with the tumor-bearing mice, the tumor-bearing mice with immune reconstitution showed prolonged incubation period of tumor formation, slower tumor growth rate and increased survival rate. Human IgG and CD3+T cells were detected in the peripheral blood of the mice 1 week after human PBMC injection. The percentage of CD3+T cells in the spleen cells was 55.3%at 9 weeks in tumor-bearing mice with immune reconstitution and 52.7% in tumor-bearing mice without immune reconstitution. The spleen index of the tumor-bearing mice with immune reconstitution was much higher than that in mice with only immune reconstitution and the control mice (9.64 vs 3.82±0.31 and 1.51±0.14 mg/g). Conclusion A stable NOD/SCID mouse model with immune reconstitution has been established successfully, which shows immune responses to triple-negative breast cancer xenografts and allows studies of immunological therapy study of triple-negative breast cancer.

Objective To establish a NOD/SCID mouse model with human immune reconstitution and observe its immune response to human triple-negative breast cancer xenograft. Methods Twenty-four NOD/SCID mice without immune leakage were subjected to cyclophosphamide (CTX) treatment 3 days prior to immune reconstitution with human peripheral blood mononuclear cell (PBMC) injection and subcutaneous transplantation of human triple-negative breast cancer MDA-MB-231 cells, CTX treatment and PBMC injection without tumor cell transplantation, MDA-MB-231 cell transplantation only, or no treatments. The tumor growth and immune responses of the mice were observed at regular intervals. Results Compared with the tumor-bearing mice, the tumor-bearing mice with immune reconstitution showed prolonged incubation period of tumor formation, slower tumor growth rate and increased survival rate. Human IgG and CD3+T cells were detected in the peripheral blood of the mice 1 week after human PBMC injection. The percentage of CD3+T cells in the spleen cells was 55.3%at 9 weeks in tumor-bearing mice with immune reconstitution and 52.7% in tumor-bearing mice without immune reconstitution. The spleen index of the tumor-bearing mice with immune reconstitution was much higher than that in mice with only immune reconstitution and the control mice (9.64 vs 3.82±0.31 and 1.51±0.14 mg/g). Conclusion A stable NOD/SCID mouse model with immune reconstitution has been established successfully, which shows immune responses to triple-negative breast cancer xenografts and allows studies of immunological therapy study of triple-negative breast cancer.

New threats posed by the emerging circulating variants of SARS-CoV-2 highlight the need to find conserved neutralizing epitopes for therapeutic antibodies and efficient vaccine design. Here, we identified a receptor-binding domain (RBD)-binding antibody, XG014, which potently neutralizes β-coronavirus lineage B (β-CoV-B), including SARS-CoV-2, its circulating variants, SARS-CoV and bat SARSr-CoV WIV1. Interestingly, antibody family members competing with XG014 binding show reduced levels of cross-reactivity and induce antibody-dependent SARS-CoV-2 spike (S) protein-mediated cell-cell fusion, suggesting a unique mode of recognition by XG014. Structural analyses reveal that XG014 recognizes a conserved epitope outside the ACE2 binding site and completely locks RBD in the non-functional "down" conformation, while its family member XG005 directly competes with ACE2 binding and position the RBD "up". Single administration of XG014 is effective in protection against and therapy of SARS-CoV-2 infection in vivo. Our findings suggest the potential to develop XG014 as pan-β-CoV-B therapeutics and the importance of the XG014 conserved antigenic epitope for designing broadly protective vaccines against β-CoV-B and newly emerging SARS-CoV-2 variants of concern.
Angiotensin-Converting Enzyme 2 ; Antibodies, Neutralizing ; Antibodies, Viral ; COVID-19 ; Epitopes ; Humans ; SARS-CoV-2/genetics* ; Spike Glycoprotein, Coronavirus/genetics*