CSPG4 and melanoma: CD4+ T cells engineered with the aCSPG4-28ζ CAR and soluble SLAMF6 displayed a greater magnitude of CD25 upregulation in response to CSPG4+ A375M melanoma cells in comparison to the respective CAR T cells without SLAMF6 release; no significant difference was observed for engineered CD8+ CAR T cells (Figure 4C).