Bacteriology USMLE Step 1 Practice Question
A 6-year-old boy presents with recurrent bacterial sinusitis (HR 102, BP 108/70, RR 22, Temp 38.2°C). CT sinuses shows opacification of maxillary sinuses with normal neutrophil count (7,200/μL). His physician suspects an inherited complement disorder and explains that one complement fragment normally coats bacteria to promote their uptake by neutrophils and macrophages. Which complement component has this opsonization function?
Answer choices
- AC5b 9
- BFactor H
- CC5a
- DC3bCorrect answer
- EC3a
- FC4b
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