Igg Immunoglobin G

This is the only isotype that can pass through the human placenta (except for IgG2[3]), thereby providing protection to the fetus in its first weeks of life before its own immune system has developed. It can bind to many kinds of pathogens, for example viruses, bacteria, and fungi, and protects the body against them by complement activation (classic pathway), opsonization for phagocytosis and neutralisation of their toxins. IgG can cause food allergy, and in such causes delayed-onset food allergy, in contrast to food allergy by IgE, whose effects appear rapidly. [1]

Bibliography

1. http://en.wikipedia.org/wiki/IgG