A novel actor in antitumoral immunity: The thymus-specific serine protease TSSP/PRSS16 involved in CD4⁺ T-cell maturation

Abstract

The maturation of a specific subset of CD4⁺ T lymphocytes in the thymus is dependent on cortical thymic epithelial cells expressing the protease thymus-specific serine protease (TSSP, also known as PRSS16). Recently, we unveiled the involvement of TSSP in tumor suppression through its effect on the CD4⁺ T compartment.

Keywords:

• CD4⁺ T cells
• colitis-associated colorectal cancer
• thymus
• tumor suppression
• TSSP

Disclosure of Potential Conflicts of Interest

No potential conflicts of interest were disclosed.

Figure 1. TSSP mediates tumor suppression by impacting the development of fully efficient antitumor immunity. The TSSP protease is highly expressed in cortical thymic epithelial cells (cTEC) involved in T-lymphocyte maturation through cross-talk with thymocytes. TSSP activity is required for the maturation of a subset of CD4⁺ T lymphocytes. Thus, TSSP is necessary for the intra-thymic selection of a diverse repertoire of T lymphocytes (shown by multi-colored dots). In the absence of TSSP, the CD4⁺ T-cell numbers are not decreased, but the diversity of the T-lymphocyte repertoire is reduced (shown by a reduction of dot color diversity). Considering that T lymphocytes play an essential role in antitumor immunity, this defect underlies the decrease in antitumor immunity efficiency observed in the absence of TSSP.