Blood and immunity: type I interferons: 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: type I interferons

Sample item

A virus-infected cell releases a cytokine that makes neighbouring cells block viral protein synthesis and degrade viral RNA through protein kinase R and RNase L. Which cytokine is this?

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

The answer and the reasoning

C. Interferon alpha and beta

Type I interferons, alpha and beta, are produced by virus-infected cells and induce an antiviral state in neighbouring cells. They activate protein kinase R, which halts translation, and RNase L, which degrades RNA. They also increase MHC class I expression and activate NK cells.

Option by option

  • A. Interleukin-4

    Interleukin-4 directs Th2 responses and IgE production.

  • B. Granulocyte colony-stimulating factor

    G-CSF stimulates neutrophil production in the marrow.

  • C. Interferon alpha and beta (correct)

    Correct. Interferon alpha and beta induce the antiviral state.

  • D. Interleukin-8

    Interleukin-8 recruits neutrophils and has no direct antiviral action.

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 alpha and beta. Type I interferons, alpha and beta, are produced by virus-infected cells and induce an antiviral state in neighbouring cells.

Why is "Interleukin-4" not the answer?

Interleukin-4 directs Th2 responses and IgE production.

Why is "Granulocyte colony-stimulating factor" not the answer?

G-CSF stimulates neutrophil production in the marrow.

Why is "Interleukin-8" not the answer?

Interleukin-8 recruits neutrophils and has no direct antiviral action.

What concept does this question test?

It tests Blood and immunity: type I interferons in Physiology. They activate protein kinase R, which halts translation, and RNase L, which degrades RNA. They also increase MHC class I expression and activate NK cells.

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: type I interferons?

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.