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[Induction of antitumor immune response by NK-cell-sensitive target cells transfected by B7-1 gene]
1Department of Obstetrics and Gynecology, The Second Affiliated Hospital, West China University of Medical Sciences, Chengdu, Sichuan, 610041 P. R. China. Yuquawei@mail.sc.cninfo.net
Objective:
To investigate whether the expression of B7-1 is involved in NK cell activation.
Methods:
B7-1 gene was transfected into K562 cell line (a sensitive target cell of NK cell, without MHC class I expression) by electropolation. Specific cytotoxicity of NK cells to B7+K562 cell was assayed by 4-h Cr release assay. The proliferation of NK cells induced by B7+K562 cell was analysed by Flow Cytometry. Expansion of NK cells and cloning of NK cells were performed by mixed lymphocyte-tumor cultures and limiting dilution analysis. Production of TNF-A, GM-CSF and IFN-A was detected by ELISA tests.
Results:
The cytotoxicity of NK cells to B7+K562 cell could be induced and that the number of NK cells could be increased by stimulation with B7+K562 cells, in particular, further enhanced with biotherapeutic agent such as OK432 and IL-2. Also, NK cell clones were established. Cytokines such as TNF- A, INF- A and GM-CSF were detected in the supernatant produced by NK cell clones. In addition, culture of lymphocytes in the presence of supernatant produced by NK cell clones and tumor antigens resulted in an increased autologous tumor killing(ATK).
Conclusion:
These findings suggest that K562 cells transfected by B7-1 gene may elicit a series of antitumor immunity and these cells may be used for further development of therapeutic tumor vaccine.
Insights
Introducing B7-1 gene into K562 cells enhances natural killer (NK) cell antitumor immunity. This approach stimulates NK cell proliferation, cytotoxicity, and cytokine production, suggesting potential for therapeutic tumor vaccines.
Area of Science:
- Immunology
- Cancer Research
- Cell Biology
Background:
- Natural killer (NK) cells are crucial for innate immunity against tumors.
- The role of B7-1 costimulatory molecule in NK cell activation and anti-tumor responses requires further elucidation.
Purpose of the Study:
- To investigate the involvement of B7-1 expression in NK cell activation and function.
- To assess the potential of B7-1 modified tumor cells in eliciting anti-tumor immunity.
Main Methods:
- Transfection of B7-1 gene into K562 cells (lacking MHC class I expression).
- Assay of NK cell cytotoxicity, proliferation, and cytokine production (TNF-A, GM-CSF, IFN-A) using Cr release assay, Flow Cytometry, and ELISA.
- Establishment of NK cell clones and assessment of autologous tumor killing (ATK).
Main Results:
- B7-1 modified K562 cells significantly enhanced NK cell cytotoxicity and proliferation.
- NK cell activation was further augmented by biotherapeutic agents (OK432, IL-2).
- NK cell clones produced key cytokines, and their supernatant promoted autologous tumor killing.
Conclusions:
- B7-1 expression on tumor cells can elicit a potent anti-tumor immune response mediated by NK cells.
- B7-1 modified tumor cells hold promise for the development of novel therapeutic tumor vaccines.