Immunology USMLE Step 1 Practice Question
A 13-month-old girl with no fever (37.2°C), normal vital signs (HR 110/min, RR 28/min, BP 95/60 mmHg), and normal oxygen saturation receives a Haemophilus influenzae type b conjugate vaccine. She has no active infection and normal lymphocyte count (4,500/μL). Linking the capsular polysaccharide to a protein carrier most directly improves immunogenicity by inducing which of the following?
Answer choices
- ACytotoxic T cell killing of infected epithelial cells
- BComplement activation through the alternative pathway
- CPurely T independent B cell activation with no memory formation
- DImmediate passive immunity through preformed antibodies
- ET cell dependent class switching and memory B cell formationCorrect answer
- FTLR-mediated T-independent B cell activation by polysaccharide
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