Inflammation: phagocytosis: practice question

A Pathology 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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Pathology · Inflammation: phagocytosis

Sample item

A child has recurrent pyogenic infections with encapsulated bacteria. Neutrophils are normal in number and kill well in vitro, but ingestion of bacteria is poor unless fresh serum is added. Which pair of opsonins most likely helps restore ingestion?

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

The answer and the reasoning

B. IgG and C3b

Phagocytes bind particles coated with IgG (through Fc receptors) and C3b (through complement receptor CR1). Opsonisation increases ingestion before the phagosome fuses with a lysosome. C5a is a chemotactic factor rather than an opsonin.

Option by option

  • A. Fibronectin and histamine

    Histamine is a vasoactive mediator and does not opsonise bacteria.

  • B. IgG and C3b (correct)

    Correct. IgG and C3b are the principal opsonins recognised by neutrophil receptors.

  • C. IgM and C5a

    C5a attracts neutrophils but is not an opsonin, so this pair is incorrect.

  • D. IgE and C1q

    IgE is mainly involved in mast cell activation and not in phagocytic uptake.

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.

More Pathology questions

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is B, IgG and C3b. Phagocytes bind particles coated with IgG (through Fc receptors) and C3b (through complement receptor CR1).

Why is "Fibronectin and histamine" not the answer?

Histamine is a vasoactive mediator and does not opsonise bacteria.

Why is "IgM and C5a" not the answer?

C5a attracts neutrophils but is not an opsonin, so this pair is incorrect.

Why is "IgE and C1q" not the answer?

IgE is mainly involved in mast cell activation and not in phagocytic uptake.

What concept does this question test?

It tests Inflammation: phagocytosis in Pathology. Opsonisation increases ingestion before the phagosome fuses with a lysosome. C5a is a chemotactic factor rather than an opsonin.

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 Inflammation: phagocytosis?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.