Related Experiment Videos
EL-4 metastases in spleen and bone marrow suppress the NK activity generated in these organs
Abstract:
The relationship between metastatic cells in the spleen and bone marrow of tumor-bearing mice and the NK activity generated in vitro by cells obtained from these organs was investigated. EL-4 lymphoma and B16 melanoma cells injected intraperitoneally into syngeneic mice (10(6) cells/animal) killed the recipients in 16 days. These tumors had a different metastatic profile: EL-4 metastasized to the spleen and bone marrow while B16 did not. The number of metastatic cells was evaluated by plating spleen or bone-marrow cells of tumor-bearing mice in agarose cultures; in parallel, the ability of spleen and bone-marrow cells to generate NK activity in vitro was assessed. The presence of 10(5) EL-4 cells/10(6) spleen or bone-marrow cells correlated with a total lack of NK activity in these organs; in contrast, no decrease in NK activity was evident in the spleen or bone marrow of B16-bearing mice. The removal of metastatic EL-4 cells (by antibody and complement) from the spleen or bone marrow did not rescue the NK activity. The lack of NK activity in spleen and bone marrow colonized by metastatic cells was not due to induction of a suppressor cell in the host. Metastatic EL-4 cells appeared to have a direct and irreversible suppressive effect on the generation of NK activity by spleen or bone marrow. A possible cause-effect relationship between metastatic colonization of lymphoid organs and suppression of local NK activity is considered.
Insights
Metastatic EL-4 lymphoma cells in mouse spleen and bone marrow suppressed natural killer (NK) cell activity. This suppression was irreversible and directly caused by the metastatic cells, not by suppressor cells.
Area of Science:
- Immunology
- Cancer Metastasis
- Cellular Immunology
Background:
- Natural killer (NK) cells are crucial for innate immunity and tumor surveillance.
- Tumor metastasis to lymphoid organs like spleen and bone marrow can impact immune function.
- The interaction between metastatic cancer cells and local immune cells is not fully understood.
Purpose of the Study:
- To investigate the relationship between metastatic tumor cells in the spleen and bone marrow and NK cell activity.
- To determine the effect of EL-4 lymphoma and B16 melanoma metastasis on NK cell activity in mice.
- To elucidate the mechanism by which metastatic cells might suppress local NK activity.
Main Methods:
- EL-4 lymphoma and B16 melanoma cells were injected into syngeneic mice.
- Metastatic cell burden in spleen and bone marrow was quantified using agarose cultures.
- NK cell activity in spleen and bone marrow was assessed in vitro.
Main Results:
- EL-4 lymphoma, which metastasized to spleen and bone marrow, caused a complete lack of NK activity in these organs.
- B16 melanoma, which did not significantly metastasize to these organs, did not decrease NK activity.
- The suppression of NK activity by EL-4 cells was direct, irreversible, and not mediated by suppressor cells.
Conclusions:
- Metastatic colonization of lymphoid organs by EL-4 cells directly and irreversibly suppresses local NK cell activity.
- This finding suggests a potential cause-effect relationship between metastasis to immune organs and immune suppression.
- Further research is needed to understand the implications for anti-tumor immunity during metastasis.