What is the spleen's role in immune defense?

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Multiple Choice

What is the spleen's role in immune defense?

The spleen defends against blood-borne infections by filtering bacteria from the bloodstream and mounting antibody responses that tag encapsulated organisms for destruction. Its B cells, especially in the marginal zone, produce antibodies (primarily IgM) that opsonize encapsulated bacteria such as pneumococcus, Haemophilus influenzae, and meningococcus. Opsonization coats the bacteria, making them much easier for macrophages to recognize and phagocytose in the spleen’s white and red pulp. This targeted defense against encapsulated bacteria is a key reason why splenic function is so important for preventing serious bloodstream infections. The other options describe functions of other organs (pancreas, liver, kidneys) rather than the spleen’s role in immune defense.

The spleen defends against blood-borne infections by filtering bacteria from the bloodstream and mounting antibody responses that tag encapsulated organisms for destruction. Its B cells, especially in the marginal zone, produce antibodies (primarily IgM) that opsonize encapsulated bacteria such as pneumococcus, Haemophilus influenzae, and meningococcus. Opsonization coats the bacteria, making them much easier for macrophages to recognize and phagocytose in the spleen’s white and red pulp. This targeted defense against encapsulated bacteria is a key reason why splenic function is so important for preventing serious bloodstream infections. The other options describe functions of other organs (pancreas, liver, kidneys) rather than the spleen’s role in immune defense.

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