A 6-week-old infant receives the first dose of oral rotavirus vaccine under the UIP. The immune effector most responsible for protection against rotavirus diarrhoea induced by this vaccine is:
- A Secretory IgA at the intestinal mucosal surface ✓
- B Serum IgG directed against the VP7 outer capsid protein
- C Complement-mediated lysis of infected enterocytes
- D Tissue-resident CD8 T cells killing virus-infected enterocytes
Correct answer: A. Secretory IgA at the intestinal mucosal surface
Explanation
Rotavirus is a strictly mucosal pathogen confined to the intestinal epithelium, so protection correlates best with secretory IgA in the gut, which the live oral vaccine induces by replicating locally in intestinal lymphoid tissue. Serum IgG contributes only partially and correlates poorly with protection. Complement lysis and CD8 killing of enterocytes are not relevant mechanisms against this noncytopathic luminal infection, and this mucosal logic is exactly why the vaccine must be delivered orally rather than parenterally.
Reference: Nelson Textbook of Pediatrics, 22nd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.