A Coreceptor-Independent Transgenic Human TCR Mediates Anti-Tumor and Anti-Self Immunity in Mice.

Recent advancements in T cell immunotherapy suggest that T cells engineered with high-affinity TCR can offer better tumor regression. However, whether a high-affinity TCR alone is sufficient to control tumor growth, or the T cell subset bearing the TCR is also important remains unclear. Using the human tyrosinase epitope-reactive, CD8-independent, high-affinity TCR isolated from MHC class I-restricted CD4+ T cells obtained from tumor-infiltrating lymphocytes (TIL) of a metastatic melanoma patient, we developed a novel TCR transgenic mouse with a C57BL/6 background. This HLA-A2-restricted TCR was positively selected on both CD4+ and CD8+single-positive cells. However, when the TCR transgenic mouse was developed with a HLA-A2 background, the transgenic TCR was primarily expressed by CD3+CD4-CD8- double-negative T cells. TIL 13831 TCR transgenic CD4+, CD8+, and CD4-CD8- T cells were functional and retained the ability to control tumor growth without the need for vaccination or cytokine support in vivo. Furthermore, the HLA-A2+/human tyrosinase TCR double-transgenic mice developed spontaneous hair depigmentation and had visual defects that progressed with age. Our data show that the expression of the high-affinity TIL 13831 TCR alone in CD3+ T cells is sufficient to control the growth of murine and human melanoma, and the presence or absence of CD4 and CD8 coreceptors had little effect on its functional capacity. [ABSTRACT FROM AUTHOR]