Scientists from University Of California San Francisco have discovered a new type of immune cell which could have direct links with human cancer prognosis. This study was published in Cancer Cell.

It is well understood that antigen-presenting cells(APCs) within tumors typically do not maintain cytotoxic T cell(CTL) function, despite engaging them. Current cancer immunotherapies are based on enhancing the ability of host or introduced T cells to reject tumors. However efficient CTL function requires frequent repriming and abundant tumor macrophages, which capture CTL at the tumor margin, either fail to achieve this, and/or actively inhibit T cell responses.

In this study, researchers show that the abundant macrophages in tumors have a functional opposite, in the form of antigen-presenting CD103⁺DCs. These cells efficiently cross-present tumor antigens and are differentially distributed within the tumor microenvironment compared with tolerizing APCs. They also describe how intratumoral CD103⁺DCs are uniquely targetable, how their abundance is required for T cell therapy in mice, and how their transcript prevalence predicts outcome in human cancers.

This cell type discovered in this study presents opportunities for prognostic and therapeutic approaches across multiple cancer types.

Reference：

Broz M L, Binnewies M, Boldajipour B, et al. Dissecting the Tumor Myeloid Compartment Reveals Rare Activating Antigen-Presenting Cells Critical for T Cell Immunity[J]. Cancer Cell, 2014.