Which antibody is the most prevalent in the body and can cross the placenta?

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Multiple Choice

Which antibody is the most prevalent in the body and can cross the placenta?

IgG is the main antibody in circulation, making up the largest share of serum antibodies. Its monomeric form allows it to move readily through the bloodstream, and it is actively transported across the placenta by the neonatal Fc receptor, providing the fetus with passive immunity. In contrast, IgA is mainly secreted in mucosal areas as a dimer, IgM is a large pentamer produced early in responses and does not cross the placenta, and IgE functions in allergic responses and defense against parasites at relatively low levels. Thus, IgG best fits both parts of the question: it’s the most prevalent antibody in the body and it can cross the placenta.

IgG is the main antibody in circulation, making up the largest share of serum antibodies. Its monomeric form allows it to move readily through the bloodstream, and it is actively transported across the placenta by the neonatal Fc receptor, providing the fetus with passive immunity. In contrast, IgA is mainly secreted in mucosal areas as a dimer, IgM is a large pentamer produced early in responses and does not cross the placenta, and IgE functions in allergic responses and defense against parasites at relatively low levels. Thus, IgG best fits both parts of the question: it’s the most prevalent antibody in the body and it can cross the placenta.

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