Immunology USMLE Step 1 Practice Question
A 26-year-old woman presents with high fever (39.8°C), diffuse erythematous rash, vomiting, and hypotension (88/52 mmHg) two days after inserting a superabsorbent tampon. Vital signs show tachycardia (112/min) and tachypnea (22/min). Laboratory studies reveal elevated creatinine (2.1 mg/dL) and thrombocytopenia (98,000/μL). She denies recent antibiotic use. Which of the following best describes the mechanism of the toxin responsible for this syndrome?
Answer choices
- ADirect activation of guanylate cyclase
- BADP ribosylation of elongation factor 2
- CInactivation of the 60S ribosomal subunit
- DCross linking of the beta region of the T cell receptor with MHC class II outside the antigen binding siteCorrect answer
- ECleavage of SNARE proteins
- FDirect pore formation in host cell membranes by staphylococcal alpha toxin
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