Phagocytosis in immune cells

Steps:

• Define the process: Recognizing, engulfing, and digesting non-self particles describes phagocytosis.
• Identify phagocytic cells: Macrophages, neutrophils, and phagocytes generally perform this function.
• Examine T-killer cells: These are cytotoxic T lymphocytes that target and lyse infected cells.
• Select the exception: T-killer cells do not use phagocytosis.

Why D is correct:

• T-killer cells eliminate threats by releasing perforin and granzymes to induce apoptosis, not by engulfing particles (per immunology definitions of cell-mediated immunity).

Why the others are wrong:

• A: Macrophages are professional phagocytes that actively engulf and digest pathogens via lysosomes.
• B: Neutrophils rapidly phagocytose bacteria and debris during acute inflammation.
• C: Phagocytes are defined as cells that perform recognition, engulfment, and digestion of non-self entities.

Final answer: D