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
First immunoglobulin to appear following infection - 
Select and explain. 
A. IgG, B. IgM, C. IgA, D. IgE
B: IgM
Answer: B: IgM 
Explanation: IgM is a heavy molecule. - IgM molecules are polymers of five four-peptide subunits. IgM is relatively sho-lived - hence their demonstration in serum indicates recent infection. ReReference:nathanarayan & paniker's 9th edition, pg no: 98 <\p>