Enhanced Immunosuppression by TIGIT⁺CD4⁺Tregs Compared to TIGIT⁻CD4⁺Tregs. Groups of mice (six individuals per group) were subjected to i.p. injection with 1 × 10⁶ ID8 cells. Ten days following injection, splenic TIGIT⁺CD4⁺Foxp3⁺ Tregs and TIGIT⁻CD4⁺Foxp3⁺ Tregs were isolated through flow sorting techniques from various experimental groups. These isolated cells were subsequently co-cultured with normal effector T cells (CD4⁺CD25⁻ T cells) sourced from healthy mice. The co-cultures were stimulated with anti-CD3 (5 µg/mL) and anti-CD28 (2 µg/mL) at a 1:1 ratio for a duration of 24 h. Proliferation (A), apoptotic rate (B), and the secretory potential (IFN-γ and IL-4) (C and D) of CD4⁺CD25⁻ T cells were assessed and quantified. The results are represented as means ± standard deviation