Sporadic immunogenic tumours avoid destruction by inducing T-cell tolerance

Area of Science:

• Immunology
• Oncology
• Cancer Research

Background:

• T cells eliminate tumors via cancer immunosurveillance, effective against virus-associated cancers.
• Spontaneous tumors are immunogenic, but their control by T cells remains unclear.
• The immunosurveillance hypothesis suggests tumors lose immunogenicity to escape T cell recognition.

Purpose of the Study:

• To investigate if immunogenic tumors escape T cell recognition or induce tolerance.
• To challenge the prevailing immunosurveillance hypothesis for spontaneous cancers.

Main Methods:

• Generated a mouse model of sporadic cancer via spontaneous oncogene activation.
• Assessed tumor growth, immunogenicity, and T cell response in naive and vaccinated mice.
• Analyzed T cell function and tumor rejection after transplantation.

Main Results:

• Immunogenic tumors did not escape T cell recognition but induced tolerance in the primary host.
• Tumors retained intrinsic immunogenicity and were rejected upon transplantation in T-cell-competent recipients.
• Primary host tolerance was linked to the expansion of non-functional T cells.

Conclusions:

• Spontaneous, immunogenic tumors induce tolerance, not immune escape through loss of immunogenicity.
• The findings challenge the concept of cancer immunosurveillance for sporadic cancers.
• Tolerance involves non-functional T cell expansion, suggesting new therapeutic targets.