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GATE 2023 BT Q.16: solution and answer

GATE 2023 · BTQ.16 · 1 mark · MCQ

Which one of the following drugs is NOT an immune checkpoint inhibitor?

  1. (A)

    Ipilimumab

  2. (B)

    Pembrolizumab

  3. (C)

    Nivolumab

  4. (D)

    Trastuzumab

See the question in the paper
GATE 2023 BT question 16Tap to open full size

Answer and solution

ANSWER

The drug that is not an immune checkpoint inhibitor is (D) Trastuzumab.

Official answer: DSource: Official answer key, GATE 2023 BT (IIT Kanpur)

  1. Immune checkpoint inhibitors are monoclonal antibodies that block inhibitory receptors on T cells, or their ligands, so the brake on T-cell activation against the tumour is released.

  2. (A) Ipilimumab is an anti-CTLA-4 antibody. CTLA-4 competes with CD28 for B7 binding and dampens T-cell priming, so blocking it makes ipilimumab a checkpoint inhibitor.

  3. (B) Pembrolizumab is an anti-PD-1 antibody. It blocks PD-1 from binding PD-L1 and PD-L2, so it is a checkpoint inhibitor.

  4. (C) Nivolumab is also an anti-PD-1 antibody, so it is a checkpoint inhibitor.

  5. (D) Trastuzumab is an antibody against the HER2/neu receptor on breast and gastric cancer cells. It acts by blocking HER2 signalling and by antibody-dependent cellular cytotoxicity. It does not target a T-cell checkpoint, so it is the one that is NOT a checkpoint inhibitor.

  6. The answer is (D).

KEY IDEA

Checkpoint inhibitors target CTLA-4 (ipilimumab) or the PD-1/PD-L1 axis (pembrolizumab, nivolumab). Trastuzumab targets the HER2 receptor on tumour cells, which is a tumour-targeted therapy and not a checkpoint blocker.

WATCH OUT FOR

Treating every therapeutic antibody used in cancer as an immunotherapy checkpoint drug. All four names end in -mab, but only the first three act on T-cell checkpoints. Trastuzumab acts on HER2 on the cancer cell.

From the GATE 2023 BT paper. Every question of this paper · Download the full paper · All 7 Adaptive immunity questions, with notes

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