During the primary immune response, which antibody peaks first, and during the secondary response, which antibody is higher?

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Multiple Choice

During the primary immune response, which antibody peaks first, and during the secondary response, which antibody is higher?

The key idea is how antibody classes change between primary and secondary responses. In a first exposure (primary response), naive B cells start by producing IgM; it appears first and peaks early, though with lower affinity. Later, the response undergoes class switching to other isotypes (like IgG) that have higher affinity. Upon a subsequent exposure (secondary response), memory B cells rapidly react and predominantly produce IgG in large amounts, often much higher than IgM, providing faster and more effective protection. So the first peak in the primary response is IgM, and in the secondary response IgG is higher.

The key idea is how antibody classes change between primary and secondary responses. In a first exposure (primary response), naive B cells start by producing IgM; it appears first and peaks early, though with lower affinity. Later, the response undergoes class switching to other isotypes (like IgG) that have higher affinity. Upon a subsequent exposure (secondary response), memory B cells rapidly react and predominantly produce IgG in large amounts, often much higher than IgM, providing faster and more effective protection. So the first peak in the primary response is IgM, and in the secondary response IgG is higher.

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