In blood typing, anti-A and anti-B antibodies belong to which class?

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Multiple Choice

In blood typing, anti-A and anti-B antibodies belong to which class?

Abo isohemagglutinins are predominantly of the IgM class. These are natural antibodies produced without prior exposure to the antigens, and they exist in serum as strong, pentameric IgM molecules. Their large size makes them excellent at crosslinking A or B antigens on donor red blood cells, leading to rapid agglutination and complement activation. Because IgM is large, it does not cross the placenta, which is why ABO antibodies in this context usually cause transfusion reactions rather than fetal disease. IgG can be involved in other immune responses, but the classic anti-A and anti-B antibodies from blood typing are IgM.

Abo isohemagglutinins are predominantly of the IgM class. These are natural antibodies produced without prior exposure to the antigens, and they exist in serum as strong, pentameric IgM molecules. Their large size makes them excellent at crosslinking A or B antigens on donor red blood cells, leading to rapid agglutination and complement activation. Because IgM is large, it does not cross the placenta, which is why ABO antibodies in this context usually cause transfusion reactions rather than fetal disease. IgG can be involved in other immune responses, but the classic anti-A and anti-B antibodies from blood typing are IgM.

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