Distinguishing immune cell functions

Steps:

• Recall neutrophils are phagocytes that engulf bacteria by changing shape via pseudopods.
• Recall B-lymphocytes are adaptive immune cells activated by direct antigen binding on their receptors.
• Evaluate each option for accuracy in describing both cell types.
• Select the option matching these core functions without contradictions.

Why A is correct:

• Neutrophils deform and extend pseudopods to phagocytose pathogens, while B-lymphocytes undergo activation upon antigen recognition, per immunological definitions of innate and adaptive immunity.

Why the others are wrong:

• B: Neutrophils are blood-based but B-lymphocytes circulate in blood and lymph; virus-infected cell killing is by NK or cytotoxic T cells.
• C: Both cells are found in blood and lymphoid organs; B-lymphocytes include long-lived plasma cells.
• D: Neutrophils use lysosomal enzymes for bacterial digestion, but B-lymphocytes primarily secrete antibodies, not cytokines (which are mainly from T cells or macrophages).

Final answer: A