Anti-A and Anti-B Antibodies

Question

Anti-A and anti-B antibodies
A)are considered natural antibodies.
B)are present at birth.
C)are typically IgM.
D)easily cross the placenta.
E)are considered natural antibodies AND are typically IgM.

Accepted Answer

Anti-A and anti-B antibodies are considered natural antibodies because they are present in individuals who do not possess the corresponding blood group antigen. These antibodies are typically IgM, which are produced in response to exposure to foreign antigens. They are not present at birth but develop shortly after birth as the individual is exposed to environmental antigens. Since IgM antibodies are too large to cross the placenta, anti-A and anti-B antibodies cannot easily pass from a mother to fetus, leading to hemolytic disease of the newborn in cases where the fetus has a different blood type than the mother.