Blinatumomab produces remissions in relapsed B-cell acute lymphoblastic leukaemia by a mechanism best described as:
- A An anti-CD19 antibody-drug conjugate releasing calicheamicin after internalisation
- B A bispecific tandem single-chain antibody linking CD19 on B cells to CD3 on T cells, forcing cytolytic synapse formation ✓
- C An anti-CD22 antibody conjugated to ozogamicin that inhibits protein synthesis
- D A checkpoint antibody restoring exhausted CD8 T-cell function against CD19-positive blasts
Correct answer: B. A bispecific tandem single-chain antibody linking CD19 on B cells to CD3 on T cells, forcing cytolytic synapse formation
Explanation
Blinatumomab is a bispecific T-cell engager (BiTE): two single-chain variable fragments joined head to tail, one binding CD19 on malignant A cells and one binding CD3 on T cells. This physically bridges the two cells and triggers perforin-mediated killing independent of MHC presentation. Inotuzumab ozogamicin is the CD22 antibody-drug conjugate, and blinatumomab is not a checkpoint inhibitor.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.