Immunology USMLE Step 1 Practice Question
A 42-year-old man who works in a wool processing factory presents with a painless black eschar on his forearm surrounded by marked edema. Vital signs show BP 128/82 mmHg, HR 92/min, RR 16/min, temperature 37.8°C, and SpO2 98% on room air. Culture confirms Bacillus anthracis with elevated protective antigen levels. He denies respiratory symptoms or fever. Which toxin component increases intracellular cyclic AMP to produce the characteristic edema?
Answer choices
- AEdema factorCorrect answer
- BHeat stable toxin
- CShiga toxin
- DAlpha toxin
- ELethal factor
- FAnthrax toxin receptor 1
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