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NK cells and NKT cells collaborate in host protection from methylcholanthrene-induced fibrosarcoma
M J Smyth1, N Y Crowe, D I Godfrey
1Cancer Immunology, Peter MacCallum Cancer Institute, St Andrews Place, East Melbourne, Victoria 8006, Australia.
Abstract:
NK1.1(+) V(alpha)14J(alpha)281(+) (NKT) cells can be induced by IL-12 therapy to mediate tumor rejection; however, methylcholanthrene (MCA)-induced fibrosarcoma is the only tumor model described where NKT cells play a natural role in controlling tumor initiation. From our previous study in C57BL/6 mice it remained unclear whether NK cells were also involved in this natural response. Herein, to discriminate the function of NK and NKT cells, we have evaluated fibrosarcoma development in mice deficient in NKT cells, but not NK cells, and mice deficient in NK cells, but not NKT cells. The results indicate that both NK cells and NKT cells are essential and collaborate in natural host immunity against MCA-induced sarcoma. In contrast, sarcoma incidence and growth rate were reduced using IL-12 therapy, this effect was mediated in the absence of T cells (including NKT cells), but not NK cells.
Insights
Natural killer (NK) and NK T (NKT) cells collaborate to control methylcholanthrene-induced fibrosarcoma initiation. Interleukin-12 therapy reduced sarcoma growth independently of T cells, highlighting distinct roles for NK and NKT cells in tumor immunity.
Area of Science:
- Immunology
- Cancer Research
- Cellular Biology
Background:
- Methylcholanthrene (MCA)-induced fibrosarcoma is a model where Natural Killer T (NKT) cells naturally control tumor initiation.
- Previous studies in C57BL/6 mice suggested a role for NKT cells but left the involvement of Natural Killer (NK) cells unclear.
- Distinguishing the roles of NK and NKT cells is crucial for understanding natural anti-tumor immunity.
Purpose of the Study:
- To elucidate the distinct roles of NK cells and NKT cells in the natural control of MCA-induced fibrosarcoma.
- To investigate the mechanisms by which IL-12 therapy impacts fibrosarcoma development in the presence or absence of T cells.
Main Methods:
- Utilized genetically modified mice deficient in either NKT cells or NK cells to assess their specific contributions.
- Evaluated fibrosarcoma development and incidence in these distinct immune-deficient models.
- Administered IL-12 therapy to assess its efficacy and the involvement of T cells and NK cells.
Main Results:
- Both NK cells and NKT cells were found to be essential and collaborative in the natural immune response against MCA-induced sarcoma.
- IL-12 therapy significantly reduced sarcoma incidence and growth rate.
- The anti-tumor effect of IL-12 therapy was mediated independently of T cells (including NKT cells) but required the presence of NK cells.
Conclusions:
- NK cells and NKT cells play complementary and essential roles in innate anti-tumor immunity against fibrosarcoma.
- IL-12 therapy offers a potential treatment strategy by leveraging NK cell-mediated immunity, independent of adaptive T cell responses.