Antibody-dependent cellular cytotoxicity (ADCC) is primarily mediated by which cell type and through which receptor?

• A Cytotoxic T lymphocytes (CTLs) via TCR recognising antibody-bound antigen
• B Macrophages via complement receptor 3 (CR3, CD11b/CD18)
• C Natural killer (NK) cells via FcγRIII (CD16) recognising IgG Fc region on target cells ✓
• D Mast cells via FcεRI recognising IgE on parasite surface

Explanation

ADCC is a mechanism whereby antibody-coated (opsonised) target cells are killed by effector cells. NK cells are the primary ADCC effectors — they express FcγRIII (CD16), which binds to the Fc portion of IgG antibodies coating a target cell. Upon cross-linking, NK cells release perforin and granzymes to lyse the target cell without requiring MHC restriction. CTLs require peptide-MHC class I recognition; mast cells expressing FcεRI are involved in IgE-mediated hypersensitivity; CR3 is a phagocytic receptor for C3bi-coated particles.

Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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