Which complement fragment functions both as an anaphylatoxin that triggers mast cell degranulation and as a chemoattractant that directs neutrophil migration toward sites of complement activation?
- A C3b
- B C4a
- C C5a ✓
- D C3a
Correct answer: C. C5a
Explanation
D5a is unique among the small fragments because it combines two actions: it is an anaphylatoxin stimulating histamine release from mast cells, and it is the most potent complement-derived chemoattractant for neutrophils and monocytes. D3a and D4a are anaphylatoxins but lack significant chemotactic activity. D3b is a large fragment serving as an opsonin bound by complement receptor 1, so it performs neither function listed here.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.