The intramuscular introduction of CTAs through electrotransfection systemically enhances antitumor immunity. (A) The experimental procedure for cDNA-based immunization with pCAGGS-SIY-OVAII (left); pCAGGS-SIY was used as a negative control. The volume of MC38 tumors after electrotransfection of pCAGGS, pCAGGS-SIY, or pCAGGS-SIY-OVAII in the quadriceps (right) (n = 5 per group). (B and C) FCM analysis of 4-1BB, CD107a, CD127, and SLAMF6 expression in tumor-infiltrated CD8⁺ T cells on day 15 (n = 5 per group). (D) The volume of LLC tumors after electrotransfection of pCAGGS or pCAGGS-Notch2^MUT with or without anti–PD-L1 therapy in the quadriceps (n = 5 per group). (E) FCM analysis of CD8⁺ T cell infiltration and 4-1BB expression in tumor-infiltrating SLAMF6⁺ CD8⁺ T cells on day 10 (n = 5 per group); statistical analysis was performed using Student’s t test (B and C) or one-way ANOVA followed by Dunnett’s multiple comparisons test (A, D, and E). All data are representative of two to three similar experiments.