Identification of different functions of CD8 + T cell subpopulations by a novel monoclonal antibody.

The explicit identification of CD8 ⁺ T cell subpopulation is important for deciphering the role of CD8 ⁺ T cells for protecting our body against invading pathogens and cancer. Our generated monoclonal antibody (mAb), named FE-1H10, recognized two novel subpopulations of peripheral blood CD8 ⁺ T cells, FE-1H10 ⁺ and FE-1H10 ^- CD8 ⁺ T cells. The molecule recognized by mAb FE-1H10 (FE-1H10 molecules) had a higher distribution on effector memory CD8 ⁺ T cell subsets. The functions of FE-1H10 ^- and FE-1H10 ⁺ CD8 ⁺ T cells were investigated. T cell proliferation assays revealed that FE-1H10 ^- CD8 ⁺ T cells exhibited a higher proliferation rate than FE-1H10 ⁺ CD8 ⁺ T cells, whereas FE-1H10 ⁺ CD8 ⁺ T cells produced higher levels of IFN-γ and TNF-α than FE-1H10 ^- CD8 ⁺ T cells. In T cell cytotoxicity assays, FE-1H10 ⁺ CD8 ⁺ T cells were able to kill target cells better than FE-1H10 ^- CD8 ⁺ T cells. RNA-sequencing analysis confirmed that these subpopulations were distinct: FE-1H10 ⁺ CD8 ⁺ T cells have higher expression of genes involved in effector functions (IFNG, TNF, GZMB, PRF1, GNLY, FASL, CX3CR1) while FE-1H10 ^- CD8 ⁺ T cells have greater expression of genes related to memory CD8 ⁺ T cell populations (CCR7, SELL, TCF7, CD40LG). The results suggested that mAb FE-1H10 identifies two novel distinctive CD8 ⁺ T cell subpopulations. The FE-1H10 ⁺ CD8 ⁺ T cells carried a superior functionality in response to tumour cells. The uncover of these novel CD8 ⁺ T cell subpopulations may be the basis knowledge of an optional immunotherapy for the selection of potential CD8 ⁺ T cells in cancer treatment.
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