all the pathogens the mother encountered in her life (even if only through vaccination) until these antibodies are degraded. This repertoire of immunoglobulins is crucial for newborns, who are very sensitive to infections, especially in the respiratory and digestive systems.

IgG is also involved in regulating allergic reactions. According to Finkelman, there are two pathways of systemic anaphylaxis: antigens can cause systemic anaphylaxis in mice through classic pathway by cross-linking IgE