CD6 is a target for cancer immunotherapy.

Area of Science:

• Immunology
• Oncology
• Cancer Immunotherapy

Background:

• Checkpoint inhibitor immunotherapies face limitations including autoimmunity and cancer resistance.
• CD318, a CD6 ligand, correlates with cancer aggressiveness and metastasis.

Purpose of the Study:

• To investigate the efficacy of an anti-CD6 monoclonal antibody (UMCD6) in enhancing cancer cell killing by human lymphocytes.
• To explore the mechanisms by which UMCD6 affects immune cells and cancer cell survival.
• To assess UMCD6's potential for cancer immunotherapy with reduced autoimmunity.

Main Methods:

• In vitro assessment of UMCD6's effect on lymphocyte-mediated killing of breast, lung, and prostate cancer cells.
• In vivo evaluation of UMCD6's efficacy in a human breast cancer xenograft model in immunodeficient mice.
• Analysis of UMCD6's impact on immune cell receptor expression (NKG2D, NKG2A) and cytotoxic molecule production (perforin, granzyme B).

Main Results:

• UMCD6 significantly augmented the killing of various cancer cells by CD8+ T cells and NK cells in vitro, outperforming PD-1/PD-L1 checkpoint inhibitors.
• UMCD6 enhanced the in vivo killing of human breast cancer xenografts by human peripheral blood lymphocytes.
• Mechanistically, UMCD6 upregulated NKG2D and downregulated NKG2A on T and NK cells, increasing perforin and granzyme B levels.

Conclusions:

• UMCD6 demonstrates a dual capability to enhance cancer cell cytotoxicity via CD8+ T and NK cells while potentially mitigating autoimmunity through CD4+ T cell modulation.
• Anti-CD6 therapy represents a novel strategy for cancer immunotherapy, aiming to suppress autoimmunity and improve anti-tumor responses.