Tumor and Self-Recognition Induce Distinct Transcriptional Profiles in Antigen-Specific CD4 T Cells

Tumors express a wide variety of both mutated and non-mutated antigens. Whether these tumor antigens are broadly recognized as self or foreign by the immune system is currently unclear. Using an autochthonous prostate cancer model in which hemagglutinin (HA) is specifically expressed in the tumor (ProHA x TRAMP mice), as well as an analogous model wherein HA is expressed in normal tissues as a model self-antigen (C3HAHigh), we examined the transcriptional profile of CD4 T cells undergoing antigen-specific division. Consistent with our previous data, transfer of antigen-specific CD4 T cells into C3HAHigh resulted in a functionally inactivated CD4 T cell profile. Conversely, adoptive transfer of an identical CD4 T cell population into ProHA x TRAMP resulted in the induction of a regulatory phenotype (Treg) both at the transcriptional and functional level. Interestingly, this Treg skewing was a property of even early-stage tumors, suggesting Treg induction as an important tolerance mechanism during tumor development.

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