Rhesus factor is an antigen present on the surface of red blood cells of Rhesus positive individuals. Rhesus positive (Rh⁺ ) is dominant to Rhesus negative (Rh^– ). A mother with Rhesus negative blood gives birth to a baby with Rhesus positive blood and there are concerns that subsequent pregnancies will trigger an immune response.

What is a possible explanation for why subsequent pregnancies could trigger an immune response?

A. Exposure to the Rh⁺ antigen in the first pregnancy triggered the development of antibodies that could attack the blood of a future Rh⁺ baby.
B. Exposure to the Rh⁺ antigen in the first pregnancy triggered the development of specific phagocytes that could attack the blood of a future Rh⁺ baby.
C. The mother has developed passive immunity to the Rh⁺ factor.
D. The mother’s immune system has been weakened by pregnancy.

A

N/A