IgG antibodies activate the complement system effectively, bind to pathogens, neutralize many toxins, enhance phagocytosis and protect the fetus and newborn.
IgG is the most common class of immunoglobulins. IgG are the only antibodies capable of crossing the placenta during pregnancy to pass on the mother’s acquired immunities to the fetus and protect the newborn until its own immune system matures. We may also say it gives passive immunity to the fetus.
IgG are found in blood, lymph, intestines, and tissue fluid.