Why does antibody-dependent cellular cytotoxicity (ADCC) effectiveness against tumors decrease as tumor cell PD-L1 expression increases?

💡 Explanation

ADCC relies on T-cells to eliminate antibody-bound tumor cells; because PD-L1 on tumor cells binds to PD-1 on T-cells, it inhibits T-cell activation. Therefore, ADCC effectiveness is reduced, rather than enhanced autophagy, glycosylation changes, or complement inhibition being primary factors.

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