Blood and immunity: macrophage activation by interferon-gamma: practice question

A Physiology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Physiology · Blood and immunity: macrophage activation by interferon-gamma

Sample item

A boy has recurrent disseminated infection with weakly pathogenic mycobacteria. Genetic testing shows a defect in the receptor for the cytokine that Th1 cells use to activate macrophages for intracellular killing. Which cytokine is this?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

C. Interferon-gamma

Th1 cells secrete interferon-gamma, which activates macrophages to kill intracellular organisms such as mycobacteria. Defects of the interferon-gamma and interleukin-12 axis cause susceptibility to mycobacterial infection. Interleukin-4 and 5 belong to the Th2 pathway, and interleukin-10 is suppressive.

Option by option

  • A. Interleukin-10

    Interleukin-10 dampens macrophage and T-cell responses.

  • B. Interleukin-5

    Interleukin-5 supports eosinophil production.

  • C. Interferon-gamma (correct)

    Correct. Interferon-gamma drives macrophage killing of intracellular organisms.

  • D. Interleukin-4

    Interleukin-4 drives Th2 differentiation and IgE production.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Physiology question

What is the answer to this Physiology question?

The best answer is C, Interferon-gamma. Th1 cells secrete interferon-gamma, which activates macrophages to kill intracellular organisms such as mycobacteria.

Why is "Interleukin-10" not the answer?

Interleukin-10 dampens macrophage and T-cell responses.

Why is "Interleukin-5" not the answer?

Interleukin-5 supports eosinophil production.

Why is "Interleukin-4" not the answer?

Interleukin-4 drives Th2 differentiation and IgE production.

What concept does this question test?

It tests Blood and immunity: macrophage activation by interferon-gamma in Physiology. Defects of the interferon-gamma and interleukin-12 axis cause susceptibility to mycobacterial infection. Interleukin-4 and 5 belong to the Th2 pathway, and interleukin-10 is suppressive.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Blood and immunity: macrophage activation by interferon-gamma?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.