This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Immunoglobulin transpoed through the placenta is 
Select and explain. 
A. IgA, B. IgG, C. IgM, D. IgE
B: IgG
Answer: B: IgG 
Explanation: IgG is the only immunoglobulin class to cross the placenta and therefore is the most abundant immunoglobulin in newborns. Isotype-specific transpo of IgG across the placenta occurs with a preference for IgG1 and IgG3 subclasses.IgG also mediates opsonization of antigen through binding of antigen-antibody complexes to Fc receptors on macrophages and other cells.IgM is a Millionaire molecule, largest. IgA - Secretory Ig. IgE - AnaphylaxisJawetz 27e pg: 137