CD4 and central nervous system cancer: Notably, the glioblastoma-specific mutation EGFRvIII has been targeted in glioma models, where engineered BEVs carrying EGFRvIII epitopes suppressed tumor growth and elicited Th1-skewed immune responses characterized by CD4+ and CD8+ T-cell infiltration [52], underscoring the translational potential of BEV-based platforms in glioma immunotherapy.