(107) observed in a B-cell lymphoma model that 72% of tumor apoptosis events in CAR8 T cell-treated mice were mediated by direct cell contact, whereas over 80% of apoptosis events in CAR4 T cell-treated mice occurred without direct interaction, suggesting that CD4+ CAR T cells are more effective in host immune activation but less so in direct tumor killing (Figure 3E). Here, CD4 is linked to neoplasm.