mRNA COVID-19 vaccines (BNT162b2, mRNA-1273) differ from conventional protein subunit vaccines in a key immunological advantage. This is:
- A mRNA vaccines stimulate only humoral immunity; protein vaccines stimulate both humoral and cellular
- B mRNA is translated by host ribosomes, presenting endogenous antigen on MHC class I to CD8+ cytotoxic T cells in addition to MHC class II/CD4+ and B-cell responses — generating broader cellular and humoral immunity ✓
- C mRNA vaccines cannot be updated to address new variants, unlike subunit vaccines
- D mRNA integrates into the host genome, providing lifelong immunity
Correct answer: B. mRNA is translated by host ribosomes, presenting endogenous antigen on MHC class I to CD8+ cytotoxic T cells in addition to MHC class II/CD4+ and B-cell responses — generating broader cellular and humoral immunity
Explanation
mRNA vaccines are translated by host cell ribosomes producing spike protein endogenously, which is processed via the MHC class I pathway and presented to CD8+ CTLs, in addition to generating CD4+ T-helper and B-cell responses via MHC class II and antibody production; this intracellular protein synthesis-based presentation mirrors natural infection. Protein subunit vaccines are extracellular and primarily stimulate MHC class II/humoral responses. mRNA does not integrate into DNA. mRNA platform allows rapid sequence updating for new variants.
Reference: Ananthanarayan & Paniker's Textbook of Microbiology, 11th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.